CLASSIC HIFI: Revived, Restored, Upgraded & Reviewed.

This is Page 2 covering 1972 to date.

See our FULL REVIEWS INDEX 1957 to Date on the MAIN PAGE

*** Note the ↑ takes you to the INDEX on the main page.



1972 Akai AA-5800 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. 45w.
Diff. FC. The build quality of this suggests 1971, appears in the 1974 HFYB for £178 & it's in the 1973,1974 & 1975 Akai Magazine until the lesser AA-5810 replaces it. But the 11.5kg quality is too good for 1973 so to assume 1972 late model before the cost cutting took over, the AA-8080 receiver below is totally different in build & quality to this. User manual also shows the 1970 AA-8500. Gold anodised front fascia & bright polished steel rotary knobs with deep grip grooves remind us of earlier styling. Rated Power is 45w/45w if a 90w total, so a true 45w unlike the AA-8080 rating. AA-5800 top model in the AA-5500 30w & AA-5200 20w range, not a mid range as a 5000 series on other brands suggests. Not one we've seen before if maybe it sold better outside UK who would have considered £178 a lot higher than other 40w-50w amps if in line with Luxman & Marantz, so still the quality of the earlier Akai. An IC inside may worry, but it's only for the Stereo Mic stage, the Phono, Tone etc are all Transistors. Plug-In amp boards, upright transistors to save space & Tantalums, build-maker is like the 1970 Akai AA-8500 receiver we had, as in these brands swapped the factory who built these as Yamaha reveal too. Unusually it's a Fully Complimentary design which could date it to 1972-73 perhaps, the Yamaha CR-1000 is FC, if the build still looks very 1970-71. Possibly this was the first Fully Complimentary amp. Original outputs were 2SD218 & 2SA649 if ours has 2SA745 & 2SC1405 on the unrepaired side. Interestingly the AA-5800 manual shows the AA-5500 & AA-5200 lower models & the IC is used more as the model spec lowers, 5500 has ICs for Phono & Tone, 5200 similar if the Mic Amp goes & both 5500 & 5200 get more modest Power amp designs. Amp works & Sound after hearing a very crisp open upgraded amp the day before, the sound is small & restrained, stereo is wide & it sounds lively to show it'll upgrade well, if the dynamics are very small. Bass is limited by the design, slew rate will be quite slow here by the opinion so far. To rate it modestly as original is fair, after all it is 46 years old. It does play Rock with a rich sound that isn't often the case. Densely recorded 60s Ska is a compressed blob of sound & this is usually the best test of an amp, how good it is with reveal depth & dynamics. High Treble music is a bit untidy lacking the speed & precision as it blurs together. First listening suggests there's a decent early Relay-Differential amp in here. The Tone & Phono board look tough to work on as was the AA-8500, if the AA-5800 messy Filter stage is done better here, more like the Sony STR-6120 one. Rear Panel has 2x Phono, 1x Tuner, 1x Aux, 2x Tape inc DIN, Pre-Out Main-In that need linking bars, speakers still has the 6.3mm jack plug odd type as Spk A & screw connectors on Spk B, the labelling needs noting else no sound. 4 main caps inside aren't quite paralleled, if not for speaker outputs as FC design. The repair on the R channel shows it's the shorted outputs type fault, if the Relay you'd assume would cut out, the 1965 Sony TA-1120 apparently you can fully short & use it again 2 mins later. No relay on the 1970 AA-8500 as Capacitor Coupled, the relay here to cut out for a SCR Thyristor probably just limits speaker damage if here it got the outputs, the driver board had repairs & even the 2 adjust pots awkwardly replaced show Protection isn't all it seems. An interesting amp that fills a gap in the 1972 era. Half Recapped & Upgraded now shows the amp is no longer restrained & it sounds much more lively, a 45 year old amp may work but it sounds tired. Looking at the 1970 AA-8500 receiver inside pics this AA-5800 is not unlike in some ways. Rock sounds better but it's not got the grunt to it, if looking at the size of the transformer in the amp shows the design is still limited, if it's still a tidy sound & only from us knowing what further upgrading can bring to some amps. Ska opens up a lot better than heard before. The slew rate is audibly better if it's more a domestic 45w sound than the sort of sound 100w amps can do. A good sounding amp now if still the Power Supply & Phono to do, probably we will upgrade further if it has the basic quality heard. Looking at the circuits, it is rather dumbed down throughout, an odd concept that we've noticed in other 1971-72 amps before, like they design a top amp & don't want you to have it & dumb it down too much. Futher Upgraded and Design learnt shows this is the best Amp Akai ever designed, so naturally it was heavily dumbed down to hide so buyers don't get these rare best designs. Modest looking casework hides a great design that builds on the AA-8500 receiver design. Compared to another reference amp, the AA-8500 actually on speakers matched it very well for the clean treble & midrange, if as single output transistors, not quite the weight of the bass. Surprising to still find good amps, if some of these 1970-72 gems ended up one-year models so didn't sell much & by 1973 the cost-cutting for Discount stores lost the quality in sound. BUY-RAW RATING: Should still be useable if the underside capacitors haven't leaked, risk of lettering wearing off leaves it looking a bit tatty. COOL RATING: 7. Gold Anodised fascia with solid metal control knobs looks good & with vinyl wrapped side cheeks still has some style. (2018)


1972 Akai AA-8080 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 30w.
SC, DIFF. A more obscure Akai receiver, no easily-found service manual, similar to the AA-8030, but worth a try from Akai successes. 1972 date code inside fascia on our 2024 one. User Manual has a '73' code for the year. This is a well made heavy item for 1972, the weighty lid is like early Trio & inside it looks similar to the NAD 160 in build style. This is a nice amp with a punchy detailed sound as mostly Serviced if original. All info shows 40w, if The True Rating is actually 30w. HFN/RR reviewed this in Jul 1974 & we all consider it 40w as Akai themselves quote this as "40w one channel playing", HFN could only get 36w, but only the Service Manual says "60w RMS output" which is 30w per channel. One of the Akai good ones to go with the AA-7000 & AA-8500 above. Semi Complimentary with a Relay, not sure if a Differential as it sounds fresher. On Rock it's pretty decent, the old spec keeps it a bit off best, but the basic sound is of quality, so for a 1972 amp it has the earlier sound. Having played a 1977 amp the day before, the sound of this as original is more our style & it has good dynamics with a kick to the sound that actually betters the 1970 AA-8500 we've had. It has all the right qualities & is better than we expected as was the 1973 JVC 5521L below. Looking at the circuit to recap, it is a Differential amp, usually they aren't this detailed, shows good design as early. Recapping & upgrading the Tone & Power amp so far, with no circuit may seem reckless but we know circuits to know what they do by looking at the board now. Fidelity is much sweeter, never heard a Differential amp sounding this crisp. The main caps, Phono & Power Supply board to do & it has 2 hot resistors, one at 70°C & the other is 55°C, the hotter one naturally right on the 85°C rated small capacitors. Looking at the NAD 160 as the design looks similar, not quite but Akai makers built NAD, explaining the quality of that amp. This is a high quality amp, Akai are certainly underrated, but only the pre 1973 ranges are good, but today more known as a budget brand. You only need to see their 1970 'Pride In Quality' brochure (on HFE) to see these were more High end than Sony at the time. Now Recapped the Sound is very pleasing. On Rock it delivers the sound well with confidence, good kick & control. Pity there wasn't a 75w version of this, the sound makes you want to crank it up more. REVISITED... well sort of, if only a few months later on getting the Service Manual as we had two of these. Faults in amps can be a good excuse to dig deeper & despite us liking this amp before it had to be tamed a little as controls were noisy. Here bad power supply & hissy preamp to repair & see how feeble the spec is which is surprising for 1972, we've had 20w amps from the 1960s with better spec, all to save a few pennies. 2022 Update. Not got another one of these, if a customer wanted one Recapped & Upgraded. We managed to get a great sound from one of these, nice on speakers too. But this is Our Art of Upgrading & going way beyond a 'standard' upgrade at a realistic price. That's how some amps are, needing a lot more done. Also to get a second one shortly after & the same upgrades didn't work out, suggesting the second one was altered from the original design to cost cut further. This makes some amps by 1973 less worthy if others from the same years are much better. Some upgrade to Excellent for a big job, if others that look the same aren't so good. Confusing. 2024 Update. Get another one of these, a chance to use some of the 4ch Akai controls it was missing. 8 years later to Revisit & to see it's a First Differential design for Akai & a design free of 'a lot of the nonsense' of later years. HFE has the Manual now, having to pay $17 for one years back is how it was then. This is an Early One. The "TSC 8002" transistors you'll not find info on, but the AA-8030 gives a clue: these are the same as "8002" driver transistors that other brands used, like 1970 Sansui AA-999. To see old repairs thinking they are 'small signal' transistors shows old repaireres often just guessed, it worked perhaps but way wrong. This has the thick 3-Core mains other Akai have, but tighly bound it's now a zig-zag mess to rewire. Phono is 2 transistors per channel, Tone-Pre x2, Power Amp Different input & a sensible design on just 8 transistors, plus the Relay-Protection stage. The design is impressive, pity Akai didn't do a 50w until the 1977 AA-1050. To see design that could have been altered in the later one we had above, Differential Amps as all Hifi Amplifiers, gets more & more tamed, so to find a good early one tells. Suggests the AA-8080 could be as early as 1971, has the same sort of control knobs as the 1972 range, if some designs could have not been issued until later. The 1970 style '8002' transistors are telling. TO3 Outouts are 2SC1030 that were in 1971 amps. 1972 Date Code on a label on the inside of the fascia confirms 1972. Once Serviced & Cleaned Up it looks smart, the Akai AS-8100S 4ch receiver looks too. The sound is certainly of a Quality as found before, Wide Stereo, not Grainy if a little rolled off on Treble. Bass shows up the Spec as being a bit limited, if most Amps are. Playing more tracks, to feel the need for more Punch & Power as a 30w amp can do still. We have the 1971 Sony TA-1130 as original still, so to compare both as they certainly better a lot of Amps as original. Good to keep Amps as original to compare, if not to be used on Speakers. Here the Sony at 65w has a more open sound with more Precision. The AA-8080 we'll Upgrade & Sell on, it needs some Upgrades that we see as weak & in this one they've already been replaced, badly, probably explaining why it sat in an Attic nearly 50 years, the 'repairs' ruining the sound on Speakers. BUY-RAW RATING: Power supply board can have too-hot problems otherwise Good. COOL RATING: 7 violet-tinged fascia on later run models with decent sized controls & sensible layout, will have vinyl effect side cheeks. (2016-2024)


1972 Akai AS-8100-S 4ch receiver ↑
AS-ORIGINAL (Once Serviced): Average-Very Good. UPGRADED: Very Good. 4x 18w, 2x 40w.
4ch Bridgeable to 2ch, Capacitor Coupled. In the same range as the AA-5800 above, this is a 4ch Receiver & also a 2ch Bridgeable one too, the Earliest One we've found as the BTL Bridged mode only 1973 usually. As with the Marantz 4230 it's Capacitor Coupled, if the AA-5800 amp isn't. The Transformer has a '7207' date code & this features in a 1973 Akai brochure if the 1974 has the chunky AS-980 range. The Tuner box shows a '7133' date showing this was changed a few times before production as noted below. The AS-1080 range must be 1975 models. The sole AA-6100 amp is 4ch only. Two versions of the 8100, three by the 3 Circuit Diagrams, the AS-8100S adds the Matrix board & extra ganged control knobs. an Aug 2019 blog of ours shows slightly different power ratings in HFE, 40w is the Akai Manual one. £265 in 1974 if likely the AS-8100 S was a brief one year model, or even shorter as AS-8100. A Delightfully Sexist AS-8100S ad exists with a Male on a Bed with 4 clothed women, Joystick & the 4 Channels. The Akai here is very well made, shielded cable is heavily used. Some seems work in progress, like the 8100 was a 4ch amp only if the Bridgeable mode is called "Surround Stereo". We just saw 2x 18w & 2x 40w so it was Bridgeable if not the same as the Trio & Marantz ones. Takes learning to understand & this actually is Tone on 2 channels only, Front has Tone, Rear has a Resistor to keep levels the same. So how can you Bridge with only 2ch of Tone. Actually the 2ch of Tone with the Bass & Treble go to an Inverting board quite like the Splitter in Push Pull Amps. The Standard & Inverted Phase run from one circuit into the Bridged mode, giving more precision, if in reality ones like our 4ch amp JVC 4VN990 are as precise as any 2ch amp once done right. Design. All Transistor Amp with 4 tiny amp boards a little untidy. Main Amp circuit misses labelling R8 2.7K. Uses TO220 size 2SD313 3A 30w outputs if there are heatsink spaces for TO3. We saw there are ICs in the Preamp-Tone & Phono, these are LD3120. the manual shows these are 2 transistors plus associated resistors with NFB etc options externally. Depends what they sound like, if the AA5800 has the same ones. Teac 42708 & LD 3130 will be nearly the same & to at last see they are Basic ICs as expected & these sounded decent. The central joystick works on wheel-cog ideas on 2x 4 gang pots. A big cable plug & connector joing preamp stages & controls to be understood. Top has the Phono stage & 6 bigger Capacitors, 4 for output & 2 doubled as the Main HT caps. Looks. Front Panel has those Cookie type deep cut control knobs, one extra on the AS-8100S, central joystick, Power switch lever & 5 more for Filters, Tape etc. Headphones for Front & Rear. Rear Panel has Phono, Aux as Front & Rear, Tape 1 as 4ch with Phono & DIN inputs, Tape 2 Stereo only, Carries on the odd Akai 6.3mm jack plug Speaker 1 outputs for 4ch & Speaker 2 is the spring connectors as many used 1971-72. AC outkets & AM bar antenna plus Multivoltage. Serviced & Rewired. Came with a 3 core thicker mains so put a same thickness one salvaged from another amp to keep the cable grip tight. Try You After Servicing. FM Dial only lights up when on FM so only 'Aux • Phono' lights as a sign it's on, if high up the display so you may miss it's still on. The Bridged Mode is the Front Control & variances in use. Sound is reasonable, clean sounding with treble & bass acceptable. Volume on Headphones can go halfway without being too loud shows Gain isn't so strong. ICs no problem here, sound is reasonably smooth & precise. Gain is certainly lacking here if the Sound is Decent. Preamp-Tone. Board underneath with the ICs has a few numbering errors on the board diagram. With no board markings, this is hard to recap, the 1966 Akai AA7000 has board markings. The board layout diagram has a few component number errors too. Recapped & Upgraded. Still not as Loud as it could be, more to do & yet to try on speakers. ICs behave fine, none of the Teac AS-100 issues with deep bass if similar ICs. As it stands as Original, it's not very good at all, low volume & thin sound with no bass. Probably why it's a Rare one. There's better in it, if not an easy one. On Speakers. Not finding it so great on headphones, if much done. as Bridged on Speakers is a different thing & for a first try tried many TV shows as the sound was very decent. More to do, if like the Marantz 4230 4ch it has a pleasing sound if perhaps a little fresher. But Akai really dumbed this one down, to wonder what to do if on Speakers it comes to life. Soundstage Huge is unusual, it's like the whole wall is the speaker. 4ch Balance affects the sound so needs more. Bias. Best way is with the Fuses, set 'Mode' to Discrete, there is no 'Surround' mode as stated. Front is 1+3, rear is 2+4 if the boards & fuses differ to the manual. Manual says 35mA, if only 15mA possible at the factory setting? Hissy ICs. The gain was too low on the amp, as made, if why? Bettering the gain brings up preamp hiss that wasn't too noticeable before. the LD-3120 ICs were all hissy, as blogged Jan 2021. Got some LD-3130 ones which are identical. Bought 8 to have options. Repairs & makes a good amp useable. Triac on the power supply, some call a Thyristor if it's a 3 leg medium power transistor size. It hard cuts off a voltage to the power amp first stage, if try find an 1RC-5. NTE5463 said to be an equivalent if not really the same specs. Ours seems damaged for noises & to trigger it made the same noises even worse on turn on again. Not Sellable? This amp has always made bad noises, plus the Low Filter & the Balance joystick noises. Triac or not the problem, it still triggers the triac for several issues of operation. It plays 4ch fine but the controls get the Protection cutting out via the Triac. Despite loads done, it can't be altered to stop the issues. Let it sit for another day's opinion, knowing what it does, if why suffer rubbish features that cause bother? Didn't Survive. Sept 2022 we put 'Last Chance' on it & Feb 2023 it was still making awful loud Mains type noises on Turn On & Off, not any part the problem. Can't Use it & can't Sell it so for parts that will get use. Mains TX taken apart, no Arcing smells so the Reason why wasn't found & everything tried including using an Oscilloscope to find where the Noise may be, not the Triac. The Balance Joystick a known issue & likely this much played with so Worn Out. We certainly tried on this one, wrote much more here but as a failed amp would you risk buyinmg one? BUY-RAW RATING: See yours makes No Loud Crackles on turn on & off. Also the Joystick may be bad. Not one we recommend. COOL RATING: 7 nice looks & with Tuner lit. (2020-2021-2023)


1972 B+O Beomaster 4000 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Very Good. 40w.
CC. An improved version of the 3000(-2) with 40w now. Still a lively sound if not as high fidelity as others & we recapped our first one partly as it needed it & brought out a very nice bassline the original design hides. Only made with a black fascia that needs a well lit room to see all the buttons clearly. Probably the best sounding B+O with 40w if still a more domestic sound. B+O capacitors if not the 1976 era dark red ones are generally good on these, only later B+O from 1971 start to get to be unreliable. After having had several B+O we rate this their best one. After not having a B+O for well over a year & so many Very Good amps of higher quality, the B+O 4000 now sounds quite ordinary. Recap-upgrading but not more fine tuning betters the bass but the quality of sound is still not as precise as the big hitters on this page as the power supply is weak. Build quality is not the highest. B+O do sell more on style than sound, B+O used to be a status symbol in the 1980s, and the sound is good enough for most but our researching these amps has found it lower down the ratings on this revisit. They are also a pain to service & fitting any new power supply caps takes creativity. All 4 bulbs must be good or not all will light as with the 3000. No cloudy sliders with the 4000. All DIN sockets, with no Aux but use Tape 1 or 2. Phono is MM & all inputs have adjust pots to match the Tuner volume. Suited the Tannoy Golds perfectly sounding pretty decent with wide Stereo if lacking the ultimate fidelity of other amps as the midrange was a little soft it was still good on bass & treble. After trying the Beomaster 4400, playing the Tuner is similar on both if the Tape 1/2 inputs are a weakness on the 4000. BUY-RAW RATING: Always in need of a good Servicing, bad switches & controls are common raw. Capacitors on later B+O often bad. To take the front panel apart is risking insanity. COOL RATING: 6 this is basically the Beomaster 3000 upgraded, but the black finish is hard to see in darker rooms so loses the cool appeal to us. (2014)


1972 Harman-Kardon 930 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. 48w.
SC, Diff. The highest powered HK receiver until the ones that appear in the 1980 HFYB. Oddly there are no specs found, a 1972 test shows 48w if it puts out 32v clean sine in line with a 55w-60w amp. We've wanted to try one of these for ages, but they are hard to find. Did have what was the later 1977 if similar looking 40w Harman-Kardon 730, from looking at inside pics, found in about 1991 at a car boot for £20 when these were deeply unfashionable & did find it sounded nicer than the B+O 3000, so a need to get the 45w one. The double transformers & 4 main capacitors, a progression from the Sansui 3000A that uses separate windings from one transformer, to make the power amps an enclosed monobloc pair. It looks quite like the Teac receivers & Sansui 4000 in looks, inside quite like Trio-Kenwood, despite being a USA brand it's still made in Japan. Rare with the wood case, a plain teak lid that goes over the leatherette vinyl covered metal lid. Inside 2 transformers of good size & 4 main capacitors, not much tuner board area compared to some if AM/FM. Red lit power switch & green tuner display only lit when tuner is used. A smart looking amp. The boards are unmarked, no components noted at all is unusual. Underneath it looks 1969-71 style with Alps pots & Elna caps but not looking familiar in construction like other Japanese made amps. The added stickers to show 240v use give the idea not many were made for UK-EU sales. Proper Aux on this unlike the Sansui 4000. Transistor counts are Phono x2, Tone-Pre x4 with circuitry usually only seen in earlier amps, Power Amp is x8 with Differential, driver, bias & the driver-output PP stages, no fussy protection circuits to spoil the sound here, just a 3A fuse on the speaker outputs. the 6800µf power caps are unusually large for the era. First try it was very weak sounding as the Power Amp had aged badly in direct sunlight by the bleached wood case, but just upgrading the Power Amp brings a significant improvement with bass now & a quality of detail improved similarly, though suspect the caps were too aged for the difference. The extra separation & individuality of the double transformers is noticeable here on Stereo and headphones. The FM stage here is modest on board with 3 ICs, but it has a detailed neutral sound that is not often found, only the NAD 300 tuner sounded like this. The design of this amp, once upgraded, reveals the double power supply removes a blurriness to the sound with peaks having a separate power supply to aid definition, but as original that's not so obvious. Of amps we've upgraded, this can upgrade a lot from original as does the Pioneer SA9500, the original amp we have to rate quite averagely as even if yours has better original caps, the sound is uninvolving, maybe why it's a rarer one. BUY-RAW RATING: Good, if can sound very average until serviced. COOL RATING: 7. Without the wood case it's just a Sansui 5000 looking amp of no real style but tuner lit up it looks smart to be a 6, the rare but plain wood top lid gives it the 7. (2015)


1972 Luxman FQ-900 receiver ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: Excellent. 50w.
SC, DIFF. Based on 1968-69 BIC Lux 71/2R. Luxman, who were still called "Lux" in the UK HFN adverts, stayed obscure until the Gaudy R-1000 series 1977-78 Receivers. This amp only has FQ-900 & 'Lux Corp' plus a 'L' logo, no actual 'Luxman' word. This SQ-900 is very different, quite a rare item as £288 new in 1973 if HFYB rate the higher model FQ990 at 70w if this very similarly numbered FQ 900 is 50w as stated in the Service Manual writeup, with modest 3300µf 50v main capacitors on a Semi Complimentary-Differential power amplifier. Also previously known as 'BIC Lux 71/2R' for Worldwide Distribution by 'British Industries Corp.' if Luxman had been making their own-brand amplifiers since the early 1960s if these were for Japan only. The 71/2R version has one Aux & two buttons on the lower left for 'Tape Head' settings that were out of date past 1968 if the FQ-900 has a more useful 2 Aux inputs with one less button. 'Deluxe 140w' says the BIC manual if that'll be Music Power to assume 45w RMS here. HFE puts 1969 with 50w showing info isn't known or this is the BIC year & spec. The Phono IC has a "7223" date showing this is a mid 1972 amp plus a low serial number and parts looking of this era. 1972 it is. Online it doesn't look as good as it does sat in front of you, the heavy build quality on a bigger unit than you'd expect, 480mm wide, 170mm high if only 330mm deep not including fittings, a wood case was optional. Build quality on thicker than usual steel making the top lid unusually heavy, gives the amp a very solid feel in use. Ours has a typical Multivoltage block for 100v-117v-220v-240v, if later Luxman were always single voltage, the BIC one will likely be Multivoltage too. This uses a TV-style push button preset for FM, the 4 buttons on the right, if to press 'Manual' to use the Dial. All nicely lit with worded lights if 'Stereo' stays on always on ours. Three Choices of Tone Roll off may impress if you'll only ever use one. Attractive amp for sure & shades of the 1975 L-100 build quality. Rear has square push buttons for 2.5mm cable that's not so useful today, line of Phono inputs if no DIN socket unusually for 1972. Still has the skinny 2-core Mains cable, these Single Insulated cables were banned soon after 1972, which is why we always rewire them. This is a Customer's amp & we like this looks wise so want one as you'd expect on an unknown one that's in our type to get. The design point that to us spoils it a bit is the Phono has a large board yet an IC which for how huge that board is, why not transistors? Output Transistors are 2SD218 which are 60w 7A explaing 45-50w RMS & the "140w" Music Power Rating. Sound Quality as Original is only fairly ordinary as aged with issues like Transistor hiss & wobbly sound from bad caps and AM being silent, maybe those finding these amps aren't getting them rebuilt as beyond the aged slightly grainy sound it does show promise. Already has several repairs on three boards if the amp is in high grade externally. It appears 1972 amps are now too old to use reliably, it is 47 years old after all. Appears a bit loud on Headphones if the circuit value is less than usual. The Design is quite unique in places, the Inputs travel over 25cm with unshielded cable & PCB track against a metal panel, would prefer shielded cable or selector near the back to be fussy. Inputs board has the Phono IC & several green square-rectangles with '4.7µf' and '2R2' which are both ceramic capacitors, '2R2' isn't a resistor. On the other side of the inputs board are 2 large green resistors supposedly only 5w that get hot by the dust lines that are part of the Power Supply to get +12v. The main Power Amp HT which runs at ±42v which suggests 35w-40w now. Phono is the IC 'µA739C' if it's marked (F)U6A7739393 with the '7223' date code, appears to be a Double Op-Amp like the 1973 Sonys use similarly, the transistor is a buffer on the switches. 3300µf 50v Main Capacitors seem very modest. Tone has the varied setting levels with two transistors before tone with typical NFB for a domestic amp plus two after the tone with one being a buffer. Fairly standard design that's not as sweet or effortless sounding, it sounded rather loud & upfront as the design tells. Power Amp with Differentials is decent, has a Protection Circuit as typical. Design not unlike the Teac AS-100 from 1971 which was a variant on their 1969 receivers design. The large transformer partly sticks out the back to save on space, the H.H. Scott late 1960s receivers & 1974 Leak 2000 receiver do similar. The Circuit Design. A little hard to follow on the blurry circuit, if Aux goes to the Transistor Buffer on the side Inputs Board then goes to the "Tape out" so it says as Line Level, so doesn't go through the IC as some other amps do, the Buffer & Transistor only share Voltage. Tracing Aux it goes through some limiting resistors, these we can upgrade if this idea does usually bring Gain level issues, ie too Loud. After Loudness & Volume to the Pre-Tone Amp, two transistors with NFB for the Tone Stage, quite a bit of gain in here with two more transistors, explains their limiting. Power amp with Differential pair & a fairly typical design, whether this is the 1968-69 design or not keeps this amp as 1972 based on the earlier one. Semi Complimentary design with Protection. There is one adjust pot hidden at the lower edge for Bias on the Differentials. The Speaker outputs are tiny square push button-hole ones like the Marantz 4070 4ch amp used, best left be as in good condition. To Upgrade. As with a few other amps that have limiting resistors on the audio, this amp needs upgrading quite a bit more. To not do redesign on the amp would leave it sounding 'unexceptional' like the 1971 Hitachi receiver & especially the amp, also the Akai AA5800 all were way too dumbed down. It leaves a tame sounding amp & one this cool looking deserves to sound better. The 1978 Luxman range had a clean sound & matched our Tannoy Speakers well if they were rather cost cut and disappointing on the circuitry, as was our 1979 Luxman LX 33 valve amp. Known good potential so this one will go further on upgrades, to how we'd do it if it was ours, rare to get an Upgrade job like that. Fascia held on by a nut & 2 screws with the control knobs removed & 2 screws inside top edge. The Fascia plate is heavy solid piece like the 1966-68 Sansui 3000(A) is in quality. To only know this one amp, but seeing several old repairs is unusual in any amp. As with some early 1971 Marantz, it cheaps out using Ceramics for Tone, this is unacceptable for hifi use & surprising to see especially with the 3 switched variants for Treble, 6 variant with 4 using ceramics. First Try On Speakers Now Done. The Headphone circuit was swapped L+R as similar USA amps often are, but the value was too low so too loud. Putting a standard value in, it's a bit quiet. But to try on Speakers. It's still too quiet, Volume needs to go midway as some Sony & Sugden do. It matches our Tannoys well & tone gives a large boost, but it sounds weak. But reading our 1975 Luxman L-100 review that sounded similarly weak as did the Luxman R-1040. Not good enough really, maybe explains why the earlier Luxmans are rare, they are not punchy sounding at all, even after a lot of work. Even the 1978 ones need redesign to not be so low volume. No Pre Out-Main In to see which side is too quiet & it needs some redesign. The circuits looked good on the FQ900 if the circuit boards & internal contruction were not well considered, suggests a first design type of amp. To try more as currently it's not really 'Excellent' as upgraded if mainly for the low gain. Now Altered. Remembering similar with their R-1040, Luxman seem to hide the sound with low volume for some reason. Once done to our ideas it sounds very decent, crisp accurate treble that not many amps do, solid bass & clean midrange with Wide Stereo. As good as it ought to be, but as with quite a lot of amps, it's hidden only found by upgrading. The first try you can se we thought 'Disappointing' for the lack of proper volume. Plays Rock cleanly if some amps do it with more weight, this is more Neutral. Not the last word in finesse, if betters many amps. At 50w it's like many other similar power if not to push the gain alteration too far & lose the nice sound. A nice listen on Headphones with strong dynamics, at last we're pleased with it. On our Tannoys it has a similarly good sound, drives the speakers well, fast sound with Bass that hits you when it's there. The Tone stages are a bit odd, we found the middle of the three settings on Bass & Treble the best ones, with the Rotary controls to suit. The blurry circuit diagram is hard going on this one. A Good Luxman Amp to know though, quirky circuit boards, good design if hidden with quite a bit of dumbing down, still makes it a good one to know. BUY-RAW RATING: Ours had several old repairs, if it's 50 years old & deserves a rebuild as it was a bit ropey sounding as aged. COOL RATING: 9 Top Looker in the Wood Case. (2019)


1972 McIntosh MAC 1900 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. 55w.
SC, DIFF. The Top Hifi Brand in the USA, you can just feel the Quality in this Brand. The MAC 1900 is basically the C26 Preamplifier & MC2505 Power Amplifier plus a Tuner such as the MR73 or MR74 all combined as a Receiver. Looks very smart in the slanted leg wood case that's like the Panloc ones if minus the button & metalwork. We last had the C26/MC2505 in 2002 from getting the power amp & trying the preamps. To see these were in a higher league as was the 1968 Sony STR-6120 we had at the time also. The Macs in the cases were certainl;y very nice, if we sold them on as prices were & still are high. Prices are in the $1000-$2000 range on the MAC 1900, looking at our customer's one on the desk, the price certainly seems worth it. We looked at more McIntosh early on, but with so much Cheaper Hifi to sample, never got round to buying one & probably would have gone for this model, their 3rd receiver & the first all-transistor after the Hybrid 1965-67 MAC 1500 & MAC 1700 that had Valve Tuners. Nice to get a high grade one, to think what music it played being from Chicago, Blues & later Disco, if more probably an amp bought for parents who clearly didn't use it much. Construction is all very neatly done, the Black Painted casework like the 1971 Sony TA-2000F/3200F adds a classy quality from seeing aged bare metal. The Components used are a little surprising, they avoid anything Japanese & use UK & EU parts. Familiarity to Leak, Quad & Revox, the UK style row of push buttons like Sugden & Goodmans used, capacitors like EU amps used, the same small electrolytics like B&O use & even rather ancient hand marked pieces going back pre 1965. Fisher used similar types of parts, clearly Japan was avoided as they did take the USA amps to make & do better on. Not much USA Hifi around & even Marantz went to USA made by about 1971. These UK-EU parts may not be quite the quality of the Japanese parts is a concern. The top part has several plug-in boards looking like Quad used, a neat touch to add screw brackets to hold the boards steady. 15kg weight with the wood case itself a heavily built one. Oddities. There are some Quirks of design, there is only Phono & Tape inputs, so for Aux you need to use a Tape Input. The Speaker outputs standing like Soldiers at the back are like Marantz used on some amps, wire size limited & today on a 55w amp you'd want to use bigger cables than 5A size mains cable. Some of the main big caps are those annoying multicap cans, three capacitors in one can twice here. These are very 1963-66 style items, to still be using in 1972 is an odd one. 1972 date on the Motorola output transistors. It looks more 1968 compared to how far ahead Japanese amps were by then. The Preamp board has an error to what is fitted, not a rare occurence sadly. What Should It Sound Like As Original. The customer has used this on 117v via a transformer, if it needs setting to 240v which we did with the C26 pre years ago. Imagining a precise sound like the pre & power had, we had the Tannoys by then as well, 2002, as the Tube Technology valves. The clean sound was noted as special with a rather soft sound compared to the STR-6120 & TT valves which were a brighter sound with more Treble. The McIntosh was considered more refined & one track we've used on many amps to try to match how the McIntosh played it, took quite a while, the B+O gear couldn't get close, if a rather basic 1978 Consort CA-4000 then the 1971 Teac AS-100 did by 2012-2013, amusingly both with ICs. To have an idea of how it would sound, so to put that & then actually try it for the first time. To Play It Now. On it goes, we'll type this as we hear to give a fresh opinion. Needs a few bulbs, put it on FM & the Façile Pop of today plays nicely at least. Not perfect in use, why it's here for a Rebuild. Got it going on 2ch, the sound is very smooth, wide stereo, a little rolled off on High Treble & Bass is not really here. Using the Soundcard EQ, the 31Hz gives almost no difference, the 62Hz adds some but takes it into a bit too rich. Treble adding the highest frequencies betters. Certainly one of the Best As Original amps with a very pleasing smooth sound. 55w is a good volume on Headphones. That 'one track' we played, it does it very nicely, a track with shrill female voices mixed high often gets tangled in a poorly-resolved distortion. To compare another amp known to be so great (our design is why) takes it ahead of the Mac, if it's much upgraded & recapped. The MAC 1900 as original is exceptionally good beyond the lack of Deep Bass. Comparing to other more Precise amps, the McIntosh is actually rather Fizzy sounding which is a surprise. Amid itself it sounds pretty good, if looking at the design, to see why & to Upgrade. Looking At The Circuits. Drawn like the Fisher amps do, the style needs understanding. Preamp is first the Phono for MM, some unusual design here & telling that the Phono & Pre-Tone on one small board does lack a little. Big Tall Receiver & Small Boards with Two Stages is, just odd. The Pre-Tone uses a Differential another unusual design incorporating Tone. The Tuner has boards top & inside the Base, just Three Electrolytics shows most is Direct Coupled as is the Phono-Pre-Tone, a design feature used in modern amps with little care for Repair techs as we found with a 1993 Sony, it's unrepairable. Here this is only Preamp level, the Sony had it far more. Power Supply is another top plug-in board as are the Pre Boards. Power Amp the two boards by the Heatsinks. Not much on them either, Differential input & Autobias with Triac Protection circuit if no Relay. To see Diodes across the output Transistors is more Unusual Design, which may mean Good Ideas or maybe not. 1982 McIntosh MAC4100 is their next one in their main series, actually had the manuals since 2013 if never looked for one. Just to see what they did in 11 years. 100w. The simplified Diagram shows Op-Amps in top-end Hifi? Stuffed with ICs, it's pretty dismal. All ICs on Phono-Pre-Tone. Power Amp in transistors with the Diff, the IC is a Protection circuit. Probably Unrepairable if ICs fail, unlikely to fail, but the 1982 era stinks for this sort of design. ICs as typical with McIntosh & Fisher are their custom codes to stop you. Rack Mount Handles & EQ like JVC's SEA on the front. Prices vary online as with other Mac gear, if it seems buyers aren't seeing what we see, different world. Recapping the 1900. Done the Power Amp, Power Supply & Preamp boards. Our Upgrades are much needed to lose the fizzy sound & it still needs a bit more help to lose a dry or papery sound. This is typical of USA amps. To work out the 2 main capacitor cans with 7 capacitor stages, the bigger ones are the main HT caps & a single capacitor. On working it out, to explain why it has that 'dry' sound & nothing can be done. We've seen loads of designs to see this amp lacks the ideas the Japanese amps had, the 1965 Pioneer SX600T we had at the same time was done so nicely. It's just a different sort of sound, McIntosh is a higher rated brand than pre 1971 Marantz or pre 1970 Fisher in the USA, clearly a USA sound as different as USA driving on the right. Final Verdict. To put this as a Blog too. This MAC 1900 being a combo of the C26 preamp & MC2505 power amp is a Revisit as we had the Pre-Power in 2002. That's 21 years ago, but we had got our Tannoys that year & the Macs have been played on the Same Speakers. To not Rate it Too Highly as Original as it's with that Fizzy Sound & Lacking Bass. It does show promise. After Recapping & trying on Speakers, to find it Not Our Bag, in a similar way the 2002 Mac Preamps & Power Amp got sold on. The Strength we found back in 2002 was how it played Midrange solidly, giving a good Focus to certain tracks like a 1967 Ken Boothe LP track. It played it smoothly, but overall compared to the 1968 Sony STR-6120 we had at the time, it was recapped but later got parted out as the Power Amp board was not reliable to sell. We are UK Folks & used most to the Japanese Hifi Sound, if Family & Early Hifi of ours was UK made. The McIntosh Sound is Tailored for USA users, the Hifi Magazines when doing their 'American Letter' complained of how Bright & Brash USA Speakers were. To think of any USA Speakers Sold In The UK is minimal, their sound wasn't for UK buyers. The MAC 1900 to us is still a grainy sound despite a lot of taming in the design. The Bass is good for Rock if deeper Bass is more restrained. The Treble we found uncomfortable to listen to on Headphones. On Speakers, to play TV shows watched earlier that day. The first show was found Dull & Compressed, not a good listen. It offered a good range of sound to not want to play it further as we didn't like it. We've looked closely at the design, it's rather tamed, lots of Diodes that seem unnecessary compared to ones in the 1971 Sony TA-1130 that we blogged about to understand what it was about. McIntosh is apparently the Top USA Brand. Prices these make are ahead of brands we consider much better on certain amps. Refined Brands in the Car World live up to their Image, in Hifi we've already found 'Bang & Olufsen' far from Real Hifi, this is compared to the Best Japanese Hifi. Mcintosh make Hifi for their own Country & probably why McIntosh never were sold here beyomnd short appearance around 1973. They are set to 117v only, if can be awkwardly set to UK Voltage, proving they aren't for UK buyers. Sony offered that easy Black Voltage Change Block as early as 1965, Sansui used a Round version before swapping to this Sony one on later Sansui TR-707A. The MAC 1900 was one we wondered about for ages, earlier MA5100 from 1966 also. Good to get one to rebuild & a free try of it, as in the Recapping & Upgrading service we offer. Well Built Amp, some silly screws on the push in boards, but the circuitry is not up to the Higher Standards of the 1960s Japanese amps.BUY-RAW RATING: Should be good if grade is nice. COOL RATING: 8. Smart Looks needs the Wood Case, not Panloc, UK-Made Push Buttons as no Japanese parts used. (2023)


1972 National Panasonic (Technics) SA-6400 4ch receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 14w-20w x4, Not Bridgeable.
SC, DIFF. Large classy looking receiver, it's a bargain so with little info found on specs, it's worth a Blind Buy as Nat-Pan amps beyond their basic ones are rare items. This we thought may be a Bridgeable amp, but not so, the Manual has a "72" date & Bridgeable came in on 1973 models only as we've found. But we're not disappointed, the Build quality is a delight & plugging it in just to see what it did, the Green FM/AM tuner lights with the 11 buttons in a line having red lit words save cluttering with print. 14.8kg is heavy quality. The Seller clearly got this out of his Parent's attic as appears to be typical with these "obsolete" amps, complete with User Manual & what must be a real rarity: the SH-1010 '4 Channel Balancer' a Joystick in a case like early gaming used. But they tried it raw & it sounds like it's typically aged & noisy and appears to have trashed a speaker of theirs so they out it cheaply as they are scared of it. Power Rating. We have the Original User Manual. Music Power is meaninglesss if it makes it "100w at 8 ohm" RMS is 19w 'per channel' into 8 ohm. It sounds more Powerful in use on Speakers. 4ch total is 56w at 8 ohm which means 14w all channels playing into 8 ohm. For Germany using DIN 45 500 standard it's 4x 14w into 8 ohm. To test the Voltage output as it doesn't sound 14w at all, can drive 15" speakers with Tone. The 14w maybe 20Hz-20kHz rather than 1kHz, it did sound bass light as original as does the SA-5800 receiver does. The Bridgeable SA-6000X is 14w similarly, why make 2 at 14w per channel? Testing below reveals it's capable of 20w & the Manual shows 20w on a graph. Has lots of 4ch controls that the 1973 Trio-Kenwood KR-6340 & 1973 Marantz 4070 don't have, Acoustic Field Dimension controls, 4ch Matrix Phase at 0-90-180°, AFD on-off & 4ch Discrete. But which 4ch System isn't clear, there is no decoder, you added an external one . The Phase control is synthesising 2ch into 4ch with various circuits. Discrete is for 4ch inputs allowing AFD as 'Acoustic Field Dimension' to alter the sound balance. It's all very complex & has various Spatial Imaging Effects. Phono & Tuner are 2ch Stereo if an optimistic 4ch MPX out to a decoder for 4ch FM Broadcasts that never were made beyond BBC experimenting a few times. So what the SA-6400X is to today's user is a quality Stereo Receiver of about 20w RMS per channel, if not Bridgeable so the other L+R amps are unused. Build quality is a delight, a large 450mm wide x 370mm deep x 150mm high unit with thick steel casing, large transformer suitable for a 100w amp. The fascia window is actually Glass. The Power Amp stages are two upright plug-in ones with TO3 output transistors 2SD180 which are 50w 5A, the later 4ch amps used smaller transistors of less power. The Speaker Fuses are set high at 3A for a 20w amp suggesting this amp as with other 4ch amps is underrated. 3300µf 35v main capacitors are typical spec as with the other 2 4ch amps. The Power Supply board between the Power Amps has a Relay & a large TO3 unit "S2HB 10" with a heatsink which is actually a Bridge Rectifier with 4 legs, 8A 100v. Underneath is a complex mass of boards & wiring, many plug-in type connectors so a lot to just Service an amp like this. The advances in Tech & Build quality on this 1972 amp were simplified on the 1973 ones. Rear Speaker connectors have 3mm holes, the idea was to use bare wire with 1cm of stranded cable exposed to push in & screw onto the strands, far better than 16 fiddly screws the KR-6340 has. Max Power is 320w (320VA) & 32.4lbs is 14.7kg. To find the Service Manual, HFE has the SA-6800X one under 'Panasonic' but User Manual only. Some amateur goes through the 6800 on 'Audiokarma' but gets nowhere it seems. £19 buys a service manual supposedly but a 1-3 week wait sounds like they don't have it, we'll try. Cleaning the inside shows the rear amp stage had 8 of 10 main transistors replaced, if the exact same ones, looks like it was damaged very early on to get a repair. First Try after some basic servicing, crunchy noises in both headphones on turn on if this fades away, it's probably what scared the seller. It's very rough with levels all over the place, deep service needed. FM/AM works at least. When it stays playing correctly for the odd minute, it plays Stereo, shows promise but rough & grainy sound, as unused for 40 years. Around the Volume are 4 adjusters L-R-Front-Rear much like the Joystick will adjust. More Serviced required here as so rough, if not unexpected, good to hear it plays at least. Better now, if sound still lacking, if most raw amps have this sound. The Rear Headphones socket shows what the 4ch Matrix Phase does, it changes the L to R phasing to create a 4ch effect from 2ch. Goes Loud on Headphones if gets into the uncomfortable area revealing the limits of the design as the JVC VR 5521 did the day before, if some amps can upgrade very nicely. All very interesting, but what to do with a non bridgeable 4x 20w receiver? Maybe best to compete the Servicing, run in & sell it without recapping which knowing the KR-6340 & Marantz 4070 is a huge job. Try It Again The Next Day, get this one again. But it's had use & woken up now since part servicing. It sounds a huge amount better if low on Bass as typical design, if use the Soundcard EQ a bit. Has the National-Panasonic 'sound' as they say "out performs other brands in tonal output" in the User Manual, if using general reasons why. but the early pre Technics ranges are very hard to find, the 27w SA-5800 we had got sold too fast. Plays muddy 60s Ska tracks very cleanly which few amps can do even upgraded. Does well on Rock Guitar too, so different from the JVC the day before. Power Ratings Again. This is very confused even in the manual. 19w x4 at 8 ohm, then for DIN 45-500 spec it gives 14w x4 similarly. On Headphones with a bit of Bass EQ from the Soundcard it "sounds like a 50w amp" for the quality if still 20w. We thought the SA-5800 played loud for 23w if it read 20v clean output like 20w amps. We have the SA-5600X service manual which is 11w x4 & Bridged 2ch to 42w x2 if this is a later 'Technics' branded one if on ±21v HT, the 6400X is on ±24.9v. SA-6400X is remarkably just 17.7v clean sine before clipping (no load). The 2ch & 4ch modes make no difference to output confirming no bridging. No Service Manual found on this one, beware the cheeky pay-downloads that promise up to 3 weeks delivery & then have nothing. We'll recap & upgrade it & at least have 2 other Manuals from similar eras if to see the exact circuit is required to fully understand subtleties. Another site shows this since first looking, but $44 download is greedy & again can you trust they have it when no trace elsewhere online? Work It Out with No Manual. We've done this on a few amps but it frustrates as you never learn the Subtleties of the design & this amp is very nice sounding. Top has the Tuner & Double Power Amplifiers, underneath has two boards with components. These are numbered C4xx, C5xx, C6xx & C7xx on components meaning 4 stages. The only Manuals show the later Bridged Amps so to look at them & the SA-5800 stereo receiver we had before. Schematics are not as tidily done as some brands. 400s are Phono, 600s are the Rear Channel Phased effects, both as 2ch only. 500s are mono Mic stage with unused 500s spaces for higher models, 700s on the long thin board are Tone Stages as 4ch, so four stages. But this amp is so nicely made, it needs understanding. Nat-Pan SA-6800X manual £12 on Analog Alley needs getting so we do & these have it instantly. 6800X is the same 4ch receiver, but 42w x4. Boards we identified are as they label in the photos in the manual & all looks the same layout if higher power. Phono (400s) is 2x transistors but PNP unusually. Tone (700s) is 2x PNP on a NFB Tone stage as 4 stages for 4ch. Mic amp (500s) reveals extra circuitry for 4ch Mic Position Control. The AFD Width Control sliders on the 6400X the same as the 6800X (600s). The preamp stage may have minor adjustments in design but basically the same 6400X to 6800X beyond the Mic Panning feature. Power Amp. 6400X 19w vs 6800X 42w, basically the same design with 19w/42w changes, the same board used. The upper board connector is for Bias checking. One TX winding for Power Amp, second for Preamp & Tuner via two Regulators. Bulbs are DC which is rare have a further winding. Amp designed with Care clearly obvious if as with a lot of amps, Deep Bass isn't bothered with. 6800X is ±33v HT on the Power Amp & the 6400X is ± 24.7v HT, suggesting the 6400X is underrated. The Relay is for Speaker Protection if turns off the main HT voltges rather than on the Speaker Outputs, acting more like a Fuse. As with the Realistic-Hitachi amps, to have at least a "nearly" circuit diagram does help, here the 6400X-6800X differences are minor. 6400X Power Transformer is "SLTA5R24S" and 6800X is "SLTA5S1S" so different voltage & with 3 windings probably impossible to upgrade the Wattage with a different TX. Our 6400X says "320W" (320VA) yet the 6800X says "185w" (185VA) if generally the Full Power Draw From Mains (VA) rating differs similarly hugely on Yamaha & Pioneer high power amps if for a different rating method. Recapping now with a known circuit makes it a much easier job, just to recap to hear how it sounds as otherwise original. To work out differences 6800X to 6400X isn't too bad as the boards are the same & numbered. Recap all 4 channels the only way & the Power Supply is fiddly to do. Recapping makes the amp crisper than the aged original capacitors. As it's one to sell to not go further in upgrading, 19w receiver looks like a 60w sized one, if a great looking fascia lit up. Has the Sound Quality of a 60w amp, a fast lively sound, not a limited sound & we've not done the preamp yet. One hint we'll tell is upgrading can trip the Relay on turn-on, it needs care. Now Done & left to Run in, to give it a critical listen. The 'Tonal Output' does better some amps as Original, the design we see they roll the Treble off slightly giving a very smooth sound. Now Upgraded it shows a little but is a very tidy sound without what poor Sources could give an 'edgy' sound. Very listenable sound though. 19w isn't a high power, if it is enough on Headphones to play loudly without distortion. To wish it was a Bridgeable one as the sound is Fresh & Clean, Stereo width is good & it has the open Sound Quality of a 40w amp if not the power. The other 1971 Nat-Pan SA-5800 amp we had was with this similar pleasing sound. Great looking amp too. The 4 Channel Balancer plug in module works, using Front & Rear inputs, it does what the 4 small level pots around the Main Volume do. Onto Rock, on a 19w amp you'd not expect it to have a rich detailed neutral sound, but it does & enough Grunt to do Rock if lacking the 75w amp's Bass. Playing more tracks, the Midrange is very precise here & that outdoes quite a few amps. Biased up right runs Cool. A few days earlier, we played the 1977 Marantz 1122DC as it arrived & the 6400X now upgraded is a more captivating sound & as original the 6400X we heard played detail well. Some amps even upgraded can sound a little blurry, here the 6400X is upfront & still neutral. On Speakers. Headphones show the precise sound, it may upgrade more as up louder it can flatten off a bit if it's likely the 19w, if really is a Excellent as it is. Past Midnight, so only to play it lower volume, it does sound very decent, BBC with their Peaky Mics gives some Outdoor TV shows like "Antiques Roadshow" extra treble, the NatPan played it with no problems even with Tone added. Rich Natural sound on Voices, deep Bass played well also, if it needs Daytime levels to confirm, if it's How Good the amp plays at low volume is important. Trouble is you'll stare at the Display lights to wonder how the lighting is so smooth & miss what's on TV. At Daytime Volume sounding Great too. 20w amp still a 20w amp, but nice quality upgraded. After A While & Some Use. It developed a Hiss on one channel, wasn't there before, if That's Hifi. Fault Finding on this a Waste Of Time as to redo the lot is best. Redone, Hiss is very low again as it should be. Oddly had the same thing with the SA-5800 here at the same time. This makes them an Unreliable amp as it was Rather Noticeable on Speakers. To do other sections is a Pro Way to deal, if we Know it's a Risk in the Main Audio Stages, just Redo it, if it's quite a Job. To leave it may get Hiss on other stages, Just Do It Properly is the way, if Work Ups the Price, it's Worth It for this Amp. Comparing 23w SA-5800 with this 19w SA-6400X. It's how the Hiss was noticed, if used it before. Wattage means they sound much the same, similar year Amp means they sound much the same. The 6400X a slightly fresher sound, if 2 unused channels Live seems wasteful. To Remove the Use of the Ch 3+4 easiest by Blanking Aux 3+4 so it's not Amplifying should give a little more power in theory.
BUY-RAW RATING: Left 40 years ignored means it needs care, recapping needed on ours as issues. COOL RATING: 8 Great Fascia if Vinyl Wrap Lid just keeps it off a higher rating. (2019)


1972 New Acoustic Dimension (NAD) 160 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 45w-55w.
SC, DIFF. The nicest sounding early NAD, see 1975 for the NAD 160a, with a fine bassline & clarity though sound can vary a lot if biased wrongly & running warm. We've found the 1971 Sherwood S-7200 is almost the same design as this, if the Sherwood is a better built amp, so much is exactly the same with just a few changes, as in comparing Phono, tone, Power amp & Power Supply. so much for NAD being great, they just nicked an idea from another amp that their Japanese makers had already designed for Sherwood, talk about recycling. Has a power supply overheating to sort before it can be used safely. Unfortunately NAD power supplies on the receivers were lousy with overhot resistors, clearly no-one bothered to test these & sellers of the day used to report these as unreliable. But the few 160 or 160a's we've had always get the power supply recapped & that hot resistor replaced with a 25w one fixed to the casework. The inner of the 2 big resistors hits 90°C. This for the lack of the Bass filter circuit & the 'rare' early name one wins points on the later NAD 160a. Having got another one and now having the Circuit Diagram we got to upgrade it better. We've had a few of these now as it's an amp we like & the one we upgraded having got the circuit delivered a very fine sound. The best NAD amplifier by far & it looks nice too in the wood veneer case. This is an amp we like & have had a few now. We actually had one that failed so early that it still smelt like a new amp inside, how could NAD be so hopeless? See the 1972 Akai AA-8080 above, the boards are the same manufacturer as those who make Akai & similarities in design. The big NAD 300 receiver still has overheating regulators, then again most Yamaha of the 1973-77 ranges are similar, was it deliberate? For a midprice amp, it's good value & the fact we've had several of these means we liked it & fully upgraded one to see how it did. We rate the 160 higher AS-ORIGINAL (Once Serviced) simply for the bass-limiting circuit in the 160a, get rid of it & they are no different sounding. A seller of these at the time noted they were a bit unreliable, if only for this one issue. BUY-RAW RATING: Beware failing overheated power supplies, else beyond that it's a good amp. COOL RATING: 8 cute looking amp like the 1971 Yamahas with nice reeded control knobs & a wood veneer lid. (2014)


1972 Photax Concertone 800B amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 32w.
Cute & obscure amp together with the matching tuner, Very Good lively sound that is really just a little less focussed than others. In real Teak veneer too. A Very Good little find, nicely made & worthy of recapping to bring out the sound further. Looks quite like a Sansui in construction. It does have ICs but ones basic & early enough not to worry at this level & we still rate it a 'Very Good' for what it is, belatedly appears in the 1975-76 hifi books. MORE INFO: This Amp & Tuner are nicely made, see our Gallery photos. This played nicely. But the Awful '333' receiver below is a real mystery. We thought it needed recapping, but... BUY-RAW RATING: Good. COOL RATING: 6 wood veneer lids with basic looking fascia but with the tuner it looks cute. (2013)


1972 Photax Concertone 333 receiver ↑
AS-ORIGINAL (Once Serviced): Lousy. UPGRADED: Still Lousy. 22w.
Rare Brand is Japanese Made 'Photax Concertone'. Very little info & no Manuals. 1972-1973 made if in the 1975-76 Hifi Books, but in Hifi Fairs in 1974. "72" code on the Tuner cans so 1972 it is. £120 as a 22w Receiver in 1975 HFYB, the Sony STR 6046A, a much lesser IC amp £120 now £105 so this amp competes. Never seen any of the Brand since the Amp & Tuner pair we had as above, only a very tatty one. Photax the Camera Brand, not Concertone a Open Reel earlier Tape Brand. Terrible Plug wiring as told on a Sept 2020 blog. The Amp a Totally Blind Buy, but for liking the Amp, why not try the Receiver, the 22w one not the 10w one. Got a few 20w receivers just to see what they are like, if to try to avoid the Junk stuff. We know this would have ICs in Audio, but the Price was worth a buy. Fascia looks smart, black plastic rotaries with metal caps plus solid lever switches. Note 'Power Switch' is up in the tuner window, not 'Off' on Speakers. Out of the rather smart wood case sleeve, actually high quality Wood Effect Vinyl, maybe the Amps similar. On the Desk backwards after opening. Looks OK, several separate Boards. What's the Amp Stage? Hidden by a Heatsink thick Panel, turn it round. Oh... Those STK IC blocks. Sanyo STK031 Power Amp blocks if as early, one per channel, some later ones are L&R in one STK. The Amp is well made for what it is, Capacitor Coupling 1000µf outputs with 2200µf 70v main Capacitor. All 'Unicon' brand grey capacitors, a brand still around, look of decent quality. Preamp & Phono. Phono has 'Sanyo LD 3130' early type of IC that's the same as the Teac AS-100 Preamp ones 'Teac 42708'. Two More on the Pre-Tone plus a Transistor "693FT" which is likely a FET as "IC + FET" on the fascia. 'Sanyo STK 031' the pair of "25w Min" Rated Power Amp Modules, usually Unwelcome, if here two pieces, not the single block that Sounds awful as more limited, two later 1970s IC amps were laughably poor. Hifi from 1972 ICs? Why not, if wouldn't try one from 1975, this is 1972. Give It A High Upgrade. See what it is. No Circuit Diagram, no Board Markings. Not the Quality of the Amp & tuner, this reveals to be Sanyo quality if looks acceptable to buy it to try. Try it after each stage done, it gets a bit better, but the Sound Quality played lower volume is what keeps us at it, but volume louder & it gets loud very quick to sound Awful, overloud & Shouty. To continue assuming faults on the preamp. All Upgraded including the tricky Preamp board, the lower volume fills out with a reasonable bass, but the Circuits are lousy. Sounds OK only played low, no Hum or Noise, just Overloud & horrible. Parts Amp Now. No way to really do more with it & interest goes. A tedious amp to work on & problems a plenty. The ICs in Preamp-Phono are decent in the Teac amplifier, but not here. The STK 031 has extra resistors & film capacitors to the Datasheet so there must be the Poor Design in both Pre & Power Stages. STK are poor played loud, but this amp is the worst ever, why sell such a poor amp new. No reviews in HFN/RR if the 'Trade' at the time will have known. Not an amp we could even sell, a £50 Blind Buy answers what their Receiver is like at least. The budget build & design makes it of Zero Hifi Value rather than the ICs. Overloud Rough Design. The Sony STR 6046A is only about 16w so no point trying that, if a better Brand ICs early one is still worth considering to test. Optimistic to think it was worth a try perhaps, if no-one else tries as many Vintage as we have. This Amp was Rubbish from the Start. It's why we avoid those UK early 1970s amps & not all amps work out. Rated "Lousy" as it's of no use, never expected any amp to be this poor. Lots of bits useful for elsewhere. Is This The One... Mentioned in HFN/RR letters around 1974 as being "Substandard", quite a Dealer Uproar about it & the Brand Rubbished? Amstrad wasn't the Brand, they must be acceptable in sound, if Unreliable they were though. ICs are still of a General audio quality, STKs are much used & do sound OK if borderline Hifi for the Spec used. But to be Utter Crap, this must be 'The Stinker' amp. Sanyo itself made the '8000' amp below, it was decent, better than we thought at the time if no Sony or Sansui. All adds to the Hifi Story. Now we can break it up, lots of parts to reuse, or store 20 years. All those Fittings & Screws are useful. BUY-RAW RATING: Probably OK as barely used for poor sound. COOL RATING: 4 looks ok, just don't use it. (2020)


1972 Pioneer SX-828 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 60w.
SC, DIFF. As the SA-9500 was far better than we expected, so time to look at Pioneer afresh after the rough sound the SX-950 type has, but seeing development & a mix of ideas in these earlier ones. The SX-828 is their 60w top of the range receiver incorporating new fully complimentary design which is early for 1972, most were still semi-complimentary. A very well built receiver with top cages on the top half like the KA-6000 above has & a place for a MC Phono transformer that was an extra, unlikely many bothered. Very clear from the preamp that the SA-9500 design started here though it does still have some 1970 style boards underneath. The power supply has some heat issues. The sound is lively with good bass & the treble is of a good quality if not quite what we could get out of the SA-9500. The fascia is a particularly attractive one with the blue lights on black with purple-grey anodised controls that looks smart. The top lid is a bit thin but again smart in real wood veneer & edges. This was £281 new when the 45w Marantz 2245 was £279. This has large capacitors, decent transformer, densely packed underneath with the preamp on a classy double sided PCB. This looks a very good quality amp. The amplifier equivalent is the SA-9100 if it has extra transistors on the power amp, 11 vs 8 on the SX-828. The one we got has had little use & sounds so unlike the SA-9500 did when it arrived, the sound is like our upgraded SA-9500 became but this is all original. This amp we hear started the receiver wars, if the SX-838 is the big sized one & maybe inspired Yamaha to up their game to the CR-1000 quality. 2023 Update Looking at the 1969 Pioneer SX-2500. Long thought this to be one to Revisit. The SX-2500 from 1969 was the forerunner to this & the circuits look good. Early review here not telling too much & 9 years ago we weren't rec apping many as they still worked & the deeper upgrades were ahead. Our 2014-sold one is well pictured on our Gallery so easy to Revisit to at least look at. Not unlike the SX-2500 in looks, uses the Jumper Rods for Pre Out-Main In unlike the SX-2500 using a switch & a hidden spoiler. The last year of the Pioneer Speaker Plugs that often got thrown out with cables. Start of the Overhot Regulators as our photos show, Pioneer & Yamaha seemed not to notice. Would be our First Choice of Pioneer to revisit, if prices are getting too high for aged working amps, we'd rebuild it anyway. BUY-RAW RATING: Good. COOL RATING: 8 smart looking receiver without the gaudy looks of later Pioneer with a slanted front, purply control knobs and blue tuner. The best looking 1970s Pioneer receiver. (2014-2023)


1972 Realistic STA-220 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 60w.
CC.  Made & Designed by Hitachi with many Hitachi symbols on boards & parts. See STA-150 for Hitachi link proved to doubters. Short lived 1972 model that didn't make it to the yearly catalogs as Hitachi stopped making for Radio Shack as Fostex took over. The IA-1000 power amp board is #251839 & the STA-220 power amp board is #251968, for the IA-1000 being 1971 this has to be 1971-72. We've known of the Realistic brand sold by USA Radio Shack & UK Tandy since getting the STA-2280 below. The 1980s ones aren't so great, but the 1970s silver ones are very different quality & there are USA valve ones going back to 1960. But the higher power ones aren't much around & then we get the 1975 SA-1500 which is very impressive & then this one. Large sized receiver, 490mm wide, 383mm deep & 140mm high shows quality from the outside with the weight & the inside really is built like a tank which for 1972 is unusual & betters similar Marantz & Pioneer easily. Probably the last of the 1960s style build quality amps. A one-year model as it still uses capacitor coupling if the STA-225 that followed in 1974-75 was the Semi Complimentary type. A 1974-75 catalog findable online shows the similar Hitachi built STA-150 (31-2047) "65w RMS" likely 32.5w+32.5w as it's £199 but no STA-220. Best of Japanese build quality here. On first try it sounds aged, transistor hiss & rustling, but high power amps got used more & this is a prime example of an amp needing a full recap & upgrade. Beyond that, the sound isn't far off how the SA-1500 sounded, the tubby restricted bass, both punchy if a bit soft & blurry too with a bit of treble grain & spitting on highest treble show it needs work, but people will use good amps like this & put up with it below it's best. Front panel has lettering in white that's less readable if the room is less well lit. Sliders for Volume were a 'trend' in the era, if we'd prefer a rotary volume & balance, but not awkward to use. Loudness needs pushing in to defeat else it sounds too bassy, looking at the board this was actually a design error. For the issues here, it needs the work done save risking damaging it as there are several issues with this. The build quality is what impresses with this, just before the 1970s financial crisis a USA company could make an amp like this without needing to cost cut. Sold for $459 in 1973-74, seems this is a rare one which means no service manual, the STA-225 is totally different inside if outside looks similar, built by Fostex now. We can upgrade without manuals, but to see the circuit does help. Unlikely we'll ever find one as not even Radio Shack has any info, how many did a limited availabilty amp sell in the Oil Crisis era? Cat no 31-2051 searches show others want the manuals, but none found. But the STA-220 doesn't even show on the Radio Shack manuals site. But experience tells us what that board does, what that part is for so for us to upgrade as we've done with a few others with no manuals is possible, if takes more work as is always the way. After a clean & service it sounds more lively, the low original spec is noticeable if you can't hide the overall strong punchy sound. As with the SA-1500, deep bass is very limited for the user of the era who used cheap gear with quality amps, but the SA-1500 improved very nicely. The power amp is fitted on a frame & undoes to lever up, showing thought for servicing given which some amps like Marantz don't. The display 8v 0.25A cartridge bulbs are still buyable. Preamp recapped & new transistors, no hiss now, very silent background actually. Interesting hear the low spec of elsewhere now just the preamp is upgraded. 'Realistic' Compares, as at the same half upgraded stage, power supplies original. The tonal balance is slightly richer on the 220 as higher power if the 1500 has the same treble & midrange. 32v clean sine rates it a real 60w & the same as the 1986 STA-2280 if worlds apart in quality. The 'magic tune' is similar to what Yamaha did in 1977, touch the tuning & the meter lights, the dial pointer goes red for stereo or white if mono. A pity this has no manual as the more amps we get, the less good ones there is & this is probably the last "old style" amp & it could upgrade a lot further. Very good tuner stage too, even getting a detailed sound with wide stereo from the heavily compressed FM pop stations. The Dial Pointer shows if FM is Stereo if red & goes white if Mono as well as Mono for noisy FM Stereo changes to orange. Doesn't match the 1969 Tannoys as too midrangey, if here the Midrange control sorts that. as with the 1975 Realistic SA-1500 this got a compare after the Trio-Kenwood TK-140X. The sound certainly has quality if the part-recap so far does reveal more needs doing. But in terms of sound as part done, it's got a sound like no other 1970s amp, the sweetest treble, very well balanced sound & punchy sound. For circuits, the SA-500 amplifier from 1972-73 will have similarities if it's only 15w. Trying to work out a preamp isn't too bad, but the power amp is too tricky, if it is a Hitachi board & has some similarities to the Hitachi IA-1100 amp & SR-1100 receiver, if is a better design. The design isn't quite a standard one as the mid 3 caps reveals, if it can be worked out. It's a Hitachi design too, as the preamp reveals features like the Hitachi IA-1000 & SR-1100. We've liked the sound of this on speakers for months if now to dig deeper into the circuit as we'll never find any manual. To trace track & know design, preamp is 2 Gain stages & a Buffer. The Hitachi amps used 3 Gain stages & it was a bit too upfront. The more we look at the design of this, the more it impresses. Very few amps have the preamp then the Volume after as to design this to avoid clipping on max tone is difficult. Here it has preamp to sliders, avoiding a balance control & then to the power amp. The Hitachi 1000/1100 don't have this. The STA-220 power amp being so close to the SR-1100 & IA-1000 designs makes it easier to understand now. STA-220 is autobias (? as the STA-150 does adjust on these) so has 2 less transistors & the 3 larger caps are understood. On getting the STA-150 below, the odd white print on silver makes sense: the STA-150 has a black fascia. Either the STA-220 should have had a black fascia or they forgot to use black ink. The Volume slider controls can crackle on these from repeated use as they wear a bit, but possible to service to keep them quiet. BUY-RAW RATING: Good if the transistors used will usually be hissy which shows on speakers. COOL RATING: 7 large size with nice fascia if white print a little hard to read on silver if has a heavy walnut veneer lid that suggests the quality inside. (2016-17)


1972 Realistic STA-150 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 32.5w.
CC. Made & Designed by Hitachi with many Hitachi symbols on boards & parts. Hitachi SR-800 Main Amp board is the Same as the STA-150 even. Short lived 1972 model that didn't make it to the yearly catalogs as Hitachi stopped making for Radio Shack as Fostex took over. The IA-1000 power amp board is #251839 & the STA-150 power amp board is #251942, for the IA-1000 being 1971 this has to be 1971-72. Comparing board numbers to the STA-220, the STA-150 (31-2047) was just earlier & the STA-220 the bigger spec version. The STA-150 is the same size hwd, has a gunmetal-black fascia, no Tone on/off switch, no front Aux/Dub sockets, 2 speaker pairs & the Tone controls are L+R together, else much the same. The Amp is lighter than the 220 for no big heatsink & Amp stage tray. The Tuner stage looks the same. Power supply caps on the top & a smaller amp board. Output Transistors are on the back in small cases like the Hitachi SR-1100 uses. Underneath the preamp board is similar to the 220 if a different board #251941. The back is a simplified version of the 220 with less inputs, if the odd 'use mains cable as FM antenna' isn't much use as it only has 2 core mains. The design here is pleasing as is the 220, build it how we want it quality, not cost cutting, a transformer like a 50w amp would have & big size to not cramp boards up. this has to be the biggest 30-35w receiver out there, if both 150 & 220 are rare. We hear in USA this was priced $349.99 if discounted to $249.99 once the next range arrived. Quite a high price for Realistic, so the next ranges were made to be cheaper for less quality. To find both as UK versions within 6 months of each other is how Hifi goes, no-one's read the STA-220 section to realise how good these Realistic-Hitachi receivers are. On first use, it's much like the 220 was, not too great as obvious hissy-noisy transistors & a bit dull sounding, if otherwise a similar sound balance with wide stereo & good dynamics. This is how vintage hifi arrives to us: tired & need of quite a bit of work. The amateur seller can say "it works" however aged it sounds. The noise here will sound on speakers & isn't really acceptable to use is the truth of it. The back transistors get a bit warm too, showing it badly needs servicing & adjusting at the very least. To us, doesn't matter as we'll upgrade it, but to you buying it, we think you'd complain it was noisy. Output transistors are 50w rated 2SD180. After servicing & adjusting, to try it. Some sort of AC bias is the 2 pots nearer the mid of the amp, if the STA-220 needed to be fully to min & AC balance are the other 2. Totally silent with volume to zero as volume is after the Tone stage as the STA-220, a rare feature. But up the volume & it's a steady sea-shore type hiss if now no rustling, at 3 on headphones it's a loud hiss though. A softer sound with a tubby retro bass as the STA-220 had originally hides how great it sounds once upgraded. Comparing the upgraded STA-220 it's overall similar as designs are very close, the tubby retro bass now a fuller more extended bass with a crisper treble. Serviced the sound is far better, a very musical amp here. The deepest bass is lacking if it doesn't sound so tubby on the bass as it's crisper, if we can see the circuit limitations as the STA-220. Preamp has the buffer stage if only one gain stage for tone & the power amp lacks the protection stage, buffer, driver, P-P drivers, outputs. On headphones 32.5w to 60w sounds no different. We'll upgrade it like the STA-220 & then see which sounds best. Still only 2200µf main power cap at 65.6v with 70mV AC ripple, but it sounds great. Outputs clean 24v sine putting it amid 35w range. The STA-150 preamp is a more minimalist design than the STA-220 & why it sounds so like our upgraded one. On closer comparing with both STA-220 & STA-150 upgraded, the overal sound is much the same. The only real difference is at 32.5w, almost half the 60w STA-220, the dynamics are a little less hard hitting. Both are enjoyable with wide lively Stereo. The tuners appear the same boards so the same quality tuner here, ours works fine in Stereo, touching the Tuning knob changes the meter colour as does FM Stereo-Mono or using the Mono switch. The Volume slider controls can crackle on these from repeated use as they wear a bit, but possible to service to keep them quiet. BUY-RAW RATING: Good if the transistors used will usually be hissy which shows on speakers. COOL RATING: 7 large size with nice fascia, has a heavy walnut veneer lid that suggests the quality inside. (2017)


1972 Rogers Ravensbrook Mk III receiver ↑
AS-ORIGINAL (Once Serviced): Average. UPGRADED: n/a. 15w.
SC, Transformer coupled. The Rogers brand was only ever Midprice on the Cadet series, earlier ones & the HG88 were aiming at a Higher Quality, but the two big selling Transistor amps Ravensbrook & Ravensbourne are very lousy. Very basic UK crap thing played very loud on headphones as was not a standard design but sophisticated it wasn't even on speakers and well made it wasn't either. Cheap retro appeal is about it's lot. Cheaply made was it & after the Valves until the A75 Panthera Rogers are best avoided as pretty much junk. Front panel flexes on the controls as so cheap. Oddly had coupling transformers in the output stages but very hard to bias so will likely run too hot. Surprising what crap was sold in the 1970s when there were much better amps from UK manufacturers. Just not very impressive, we see buyers paying too much for these Ravensbrook & Ravensbourne amps, but we'd not try one again, the rating is harsh but we don't really see a 'Recommended' in it. REVISITED 2016 IN THEORY: Looking at our pics, the amp innards are made like a 1960s EU radiogram, it has a one-board amp-phono-power amp-power supply if the tuner is on another board, as it's a combo of amp & tuner in one. Upgradeability would be possible but not worthwhile. It still looks cheap junk & one in person is cheap junk as you'd find. The ROGERS RAVENSBOURNE amp developed into later models but is a better quality 45w version, if that's foolishly hidden as 25w into 15 ohms in the spec. But again axial caps, not worth us trying having to recap those & not be able to give it the quality. This is why we generally avoid UK amps: axial caps. BUY-RAW RATING: Good if usually full of dust & much from casing gaps. COOL RATING: 6 wood veneer case & minimalist design looks smart if cheaply made. (2012)


1972 Rotel RX-800 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 40w.
SC, DIFF, Relay. Been a long wait to find one of these, we saw the EU version with DIN sockets ages ago, if we've got the UK one. Rotel didn't make many receivers, the 1970 FAX-660 was only 30w & we've never seen one to try. 1974 HFYB has RX-800 (800A is a typo?) 60w into 4 ohms-40w into 8 ohms £178 as on our List of Receivers page & by 1976 it was replaced by the RX-802 55w at £222+VAT. The fascia has a nice look with the Tuner Dial & 2 meters, a line of buttons including a dimmer swich for the lights & what looks like a line of LEDs, if they are 5mm bulbs. Below is a aluminium panel with the rotary controls. It looks very purposeful, if sadly the lid is only a vinyl wrap if a well made one, it may fool you it's wood. The back doesn't look like any other amp brand with an unusual AM antenna hinged part, 2x Phono, 2x Aux & 2x Tape by Phono inputs plus Tape DIN pair. Pre Out-Main in connectors & 3 fuses. Some sort of pseudo 4-ch effect with the rear switch, 2 pairs of speaker sockets like the Marantz type spring connectors & a 3-core mains. Inside has the power amp board plugging in between the heatsinks, Tuner early stage under a metal cover with an upright board on the right that is the Phono stage with a metal shield. The Tuner front-end has '7245' date in the same style that Yamaha used. Underneath has 2 slim boards like the Sansui AU-999 has plus another metal cover over the base of the main tuner. Two front boards for Preamp & Tone. Sold as a non-worker but worth a gamble. No-one's been inside it before & it looks good & a few tests say good too. Why doesn't it work? The rear 3 fuses... are empty, nothing in there. We know this one from being a kid, the parents take out the fuses to stop you using the 'Stereo' because you were naughty. Re-fused, a bit of a 'dry service' & plug it in. Why it had no fuses makes sense now, unusual fault but we like this amp so it'll be fixed, not a quick repair, needed a major rebuild on the power supply. Strange how someone kept the amp for at least 42 years without getting it fixed, a few bulbs out, maybe it got 2 years' light use. Now playing Music likely for the first time since 1974, obviously it's been long asleep. An amp unused for this long has stiff rotary controls & quite a dull sound that does awaken a bit. A bit perfumey smelling with non-smoker dust says it was a woman's amp & be sure with the sound we can hear already they were upset it failed so kept it for so long. If bought by a 35 year old in 1973 she'd be 77 now, time doesn't stand still & only likely cleared out for life status. Tuner works fine too. For left unused for so long & stored inside in the warm, it'll never awaken enough, so an amp like this would need a recap to bring the crisp sound back as it's too warm sounding, needing +2 on Treble & -2 on Bass to sound more normal. Service Manual on HFE & elsewhere is a lousy photocopy job & it misses half of the tone stage board. As the pdf versions are all incomplete, missing an unknown amount of the Tone stage & poor quality, this rare amp deserves better so £17 to buy a real printed one from Canada makes sense, 14 days by Surface post. The pdf versions actually only miss about 1cm of the printed version but without it you'd never know. The boards with circuit numbers are unreadable and as the boards aren't numbered to follow the circuit would get errors. The Power Amp is of a good design differentials, driver, bias, p-p drivers & output. Relay is the protection circuit. Tone is 2 transistors. Phono is 3x PNP transistors unusually if typical for the era. The manual shows the power amp plug in board varied probably due to available plug-in sockets from the very early ones, ours is the AF-33D one if Phono board the upright one on the top right changed from 2 to 3 transistors by the Apr 1973 dated manual. If you have the 2 transistor phono, no circuit shown. First try once the Power Amp recapped, one leaky capacitor shows to use an amp long unused wouldn't last long, if now sounds a lot more as you'd expect. Needs about 10 mins to run in new caps. Now reveals the weaknesses in the preamp & input stage, volume at midway shows gain isn't as good as it should be at 40w. Some alterations later, better volume & better sound. Testing a few tracks & it's now a very different amp. Punchy amp now if the ceramics still sound on the preamp. Has Tone Defeat switch much like the Heathkit AR-1500 which does make a difference to the sound until it's upgraded. As with the Heathkit, another great sounding Differential amp, proving not the Differential the problem in later amps, but poor design & over-design. The sound does remind more of the Heathkit than the Realistic STA-220, a more weighty sound. Fair to say even at this stage, the best Rotel we've heard, the later RX-603 was nowhere as lively as this. An unusual sound, good volume, crisp treble, rich sound with a precise sound with deep soundstage & punchy dynamics. Not the usual 40w sound, if that's why it was dumbed down. Time to try on the Tannoys, DC offset is fine with a test speaker load. Matches very well, very clean punchy sound with crisp treble & thundering bass. In comparing to the STA-220 after using the Rotel on the speakers for a few days, the tonal balance is different. The STA-220 is a more open sound, the Rotel is more 'designed' to sound more punchy on cheaper speakers & impress you. It's a more Domestic type balance, plays well at low volume & doesn't sound thin. A great amp to have tried if we prefer the more open PA type sound on speakers. The sound of this will compliment most speakers better than a more open sounding amp that can sound thin & harsh. We need to try more Rotel, the big RX-1603 type amps, if they are usually too expensive to buy to upgrade & outprice them is the risk. BUY-RAW RATING: Ours was unused for 40+ years, if should be generally good if used more. COOL RATING: 6.5. Advanced controls of a later era with lilac tinted controls if the vinyl wrap loses it half a point. (2017)


1972 Rotel RX-400A receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Very Good-Excellent. 20w.
CC. Another Rotel for us to try. Mixed Feelings on this Brand, the 1966 100AMP was lousy. The 1977 RX-603 & huge RX-1603 were OK if a bit generic by then. But We Like the 1972 era ones. The RX as RX400L with Long Wave & RX-400A as here. RX-800 we had on 2017 if Traded for the Half Ruined Sony STR-6120 as the Sony needed a lot done for the Users' Issues. Didn't really get to Live It Fully, but that's Hifi. Nice Looks on the RX-800, the RX-400A is a 20w-ish amp & more minimal. RX-400A is the usual one online if the RX-400 looks the same, RX-400 is also a later 1980 Silver front one. 1972 HFYB lists the RX-400 if the 'A' will be 1972-73 for the FCC rules. No Filters is nice, they can be a problem in some amps. One meter, no Source Bulbs. We're trying these Lower Power Models if at least 20w to see what they are like. The Bigger Models being Overpriced meaning Rebuilding isn't Always what is a Good Deal for us to Buy. Cute Amps without a lot of the 'extras' can be Worthwhile, the 1967 Sansui 400 opened our eyes to these, 20w is enough power on Speakers that are more Efficient, sound fine on our 95dB 15" Tannoy Golds if those Speakers are Way Ahead of what these amps would usually see. Unboxing. 1978 BBC Tuning sticker plus "2" means this was likely a Middle Aged Woman's Amp, One Careful Driver. Likely a Trade-Up on a Radiogram, if they bought a better amp. Fascia is uncluttred therefore, Power, the Obligatory 2 Speaker sets, on a 20w Amp? See a Aug-Sep 2020 blog. Mode mono-Stereo, Tape & Loudness, Usual 4 Rotaries & Selector. "Series 2" sticker, to seee the changes later. Vinyl Wrap if an attractive one. Used the Antenna as a Handle & snapped it if can be fixed. Proper 3-Core Mains on the 1972 Rotels which is before 'Double Insulated' cable became Law, as in No Skinny 2 Core Mains that's Single Insulated. Multivolage, says "150w" which is High for a 20w-ish amp if 1.5A Speaker Fuses. Nice Amp, this has the Full Ply Wood Case, not just the Lid as the RX-800. Under The Case. Know it's a Transistor Amp if not looked for an inside pic to keep it a 'surprise'. Full of Dust, so Hoover it out. 63v 2200µf main cap plus Output Capacitors show it's an earlier design than the other 1972 ones. Quite an Old Fashioned Design for 1972, No Relay or Differentials. RX-400 & RX-400A only seem to differ on a quick look for the LC output device to comply with FCC rules as a sticker over printing tells. Same Amp is assumed. Inputs Phono to the Upright Board, Tape Out is Duplicated for va 4ch Idea & a Rear Switch adds this. Decent for a 20w amp inside, TO220 2SC789 outputs, 30w 4A. At this level, some Unshielded Cable on Audio Cables, but so does the Pioneer SA-9500 Mk 1. Which will be The Best from this, JVC VR-5525L & Sansui 350A in the 20w Battle? Rotel could be, No Filters, Nice Case, Aux via 15K resistor if not into Phono, No SEA Graphic. All keeps it Interesting. Sound As Original. Tried it a few days later, too hot that day & a little surprised at the build quality. Actually sounds decent for what it is, a Smooth sound with Crisp Treble if Bass isn't here if it sounds Full, not Bassy, just Underdeveloped which Most Amps are. Playing Bassy Reggae it sounds 'Boxy' on the Bass if still listenable for the Smooth Detailed sound. Rock is played with Better Focus than some & with Headphones up midway on Volume is still respectable for 20w, if what would it drive big speakers like? Capacitor Coupled amp, if 1000µf for 1972 is very low. Aux goes through Shielded cable if Tape In-Out arent, Phono isn't if the Phono Stage very close. A bit of background noise shows NFB is low explaining why it sounds good. As with the 1974 Yamaha CR-200 it could be upgraded a lot to get a better sound in the League we go to, if to be Fair this sounds like a 20w amp should, would be played low-ish volume on boxy speakers hiding what it is. Will be a Nice Amp Recapped & Upgraded, if one to Sell rather than go further with. Circuits. Lightweight amp not what we're used to, but it sounds good & the Circuits are sensible, Aux direct. Phono on the upright board with 2 Transistors per channel. Pre Amp including Tape Out which is Buffered, rare to see that in amps. Passive Tone stage. Transistor after Volume then Pre Out-Main in which again is unusual for 20w. Gain Stages if Buffers in effect to not be affected by other Impedances. The circuit is better than the amp looks which is why we got it, to try with other 20w Receivers with similar worthy circuits. Driver then P-P drivers onto Outputs. Bias stage, if no 'Protection', no real need as still Capacitor Coupled. Good design with Modest Looks. Price new not known if later prices suggest this around £110 new competing with others. Better than just a Granny amp to get rid of the Radiogram, if other UK brands pretty much were. Changes. RX-400 is different from the 400A, boards & components in the top differ. What the two 1000µf 35v caps on the rightmost MPX board do isn't told, if they are Power Supplies non MPX related for Preamp & Phono. Ours a later version, earlier ones don't have this, it updates the axial caps power supply with Full Wave rectifying & an unknown circuit, if it can be traced. Recap & Upgraded. Done it all in one go. Circuits differ in ours to the 400A circuit so care needed plus no board markings at all. Phono stage modest if Ceramics on the output coupling is Shameful, deserves better. Modest but still of Quality. Some parts like the 'P' heatsinks flapping loose need securing. Capacitor Coupled outputs on the PCB limit the size, if what we've used on 20w is fine. Tuner with a Green Display & Meter looks smart, to see it lit up again reminds why we got it. Background noise very low. First proper Play after using it a bit brings a Decent Sound. Clean Fresh sound. Bass is acceptable for 20w if playing on Headphones to find it wide Stereo with Crisp Treble, if wanting more Volume. Rock is played with Precision if rather lacking the Meaty weight of better designs, if Up The Bass to bring it better Balance. Still plays The Jam 'Start' well at +2 on Bass. Punchy Fast little amp, if it's the Upgrades. Better than Expected, the Clean Focus on 20w is still an Elusive Thing. We had the RX-800 above & seeing we liked the Sound there, if it took some upgrades as it was a bit Tamed. Rated as VG-EX as Upgraded, Treble-Mid decent, lower Mid-Bass a bit Feeble. Build Quality on this amp is Very Poor for a 1972 Amp. Cost Cut with loose critical components & an excess of Unshielded Cable, it's truly crap in several places. The RX-800 was a decent amp, this Entire Amp of Cheapness & Penny Pinching everywhere annoys us. Rotel can be Good on a Few but even the big RX-1603 didn't please with Cheapness there. Don't think we'll buy Rotel again. We'll buy certain Sony, Sansui, JVC etc all day long but Rotel are limited to a few good ones. BUY-RAW RATING: Probably works still from little use, a Granny Radiogram upgrade receiver. COOL RATING: 3 The Green Tuner Display improves it if the thin cheap fascia & crappy insides are Bad for Rotel who seem to be Very Poor Build Quality if sound OK despite more cheapness. We dont like Cheap. (2020)


1972 Rotel RA-810 amplifer ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 40w.
SC, DIFF, Relay. This is the similar Amplifier version of the RX-800 above, the same amp board. Quite different to the similar RA-610 as below, this is a bigger amp than the smaller size of the 610. Looks more 'pro' looking on the fascia too, so 'Nice Amp' is the first opinion. Insides still with the odd preamp & tine boards fixed right on the Buttons & sliders, looks a little cramped up instead of using bigger boards in the larger case. Not seen this one before, early Rotel as with the RX-800 at 40w are Rare Items. 1974 Hifi Yearbook shows the RA-810 £116 60w which is a typo as it's the 4 ohm rating, the User Manual shows 40w per channel RMS both channels driven at 8 ohms, ie a true 40w amp. That shows also there are no wood sides on this, just the vinyl covered metal lid if the controls look more 1974 & nicely made. "Possessing an abundant 180w music power" on the Manual is the sort of nonsense power rating soon outlawed, if sugary descriptions still live on. If you couldn't afford the more expensive brands, the Rotel which usually sounded better than the typical 1972 amp was a smart buy, based on the RX-800 & RA-610. the Phono board again is a small raggedy thing tucked next to the power amp if with a metal shield, Rotel overall made a great amp here if the Pre & phono boards should have been done better with more space available. Multivoltage amp with a proper 3-core cable is unusual in the 1972 era. Now all recapped, we found the volume a bit low & not good enough to return as an upgrade. But the RX-800 has similar pointless input circuit to reduce the level which is totally unnecessary. So we alter that to see how good the amp is. Now back together all clean it looks very smart, good looking amp, a similar sort of black & silver 'Industrial Look' that the Teac AS-100 has. Sound is now more the sound we expect & a lively sound here. On Rock guitar it plays it convincingly with good weight for a 40w amp, certainly betters quite a few to do that. Just a pity Rotel didn't do higher power in the era. One of those amps we could upgrade further as it has the 'right sound' & that would tighten the Focus & better the Slew Rate, it is punchy sounding if some blurring on midrange, if you'll need speakers beyond the range of this quality Midprice amp to realise. BUY-RAW RATING: Should be fine beyond usual age & servicing. COOL RATING: 6.5 Smart Silver & Black looks rather nice & the odd side fascia fin-notch panels give a bit of style. (2018)


1972 Rotel RA-610 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 32w.
SC, DIFF, Relay. Another lower powered amp with a nice sound, a little warm on midrange detail - not on the revisited one below - but nice with it to still deserve the rating. Well made semi complimentary design would upgrade up well to lose the midrange imbalance. One certainly worth buying if 32w will do, more sophisticated than the similar Leak. A nicely made amp. One we had early on in our Amp testing just to see what there was, a nice amp but not one we'd try to upgrade now as there are many better, but a good starter amp to buy. Another 2012 rated amp, Rotel are a good brand if finding ones of high power beyond the big late 70s receivers isn't easy, the 1977 RX603 reveiver below was the only other one we tried. REVISITED 2016: Not had one of these since 2012 if we liked it. 1972 is the early years of the Comet era where a lot of hifi will have been sold, if just before cost cutting got heavy by 1974. £69 new when a Sansui AU-555 at 35w was £109 puts this as midprice, but good value. Still has a good look, with Tone sliders the only difference to some amps & not a problem to use, the rest of the controls are Rotary or push-button. The Service manual available now is far better than the one we got in 2012 so can see the design better. Transistor count is still decent: Phono x2, Pre-Tone is similar to the Sony TA-1120A with x4, Power Amp x8 with obligatory differentials if a good basic circuit. Some of the design is a bit 'soft' in spec & for 32w it could be upgraded. First play of it after a service shows it has a fresh sound, the sound is decent if the usual low-spec sound, but certainly not bad. The midrange here sounds balanced, the previous one was not so accurate if hifi in this era often got dumbed down in later production models as buyers with budget gear complained. The Rotel is midprice but with a quality of sound showing more quality. Construction of the Tone & Preamp isn't great & may be tricky to upgrade. You can see we've played lots of amps now & for this to get full songs played without facial expressions when it goes rough shows the RA610 is a bit of a good amp. We can instantly upgrade the rating from 'Recommended' to 'Very Good'. The background is silent on headphones, some of the earlier amps aren't so silent. On Rock that needs some clean design & grunt, this is a little soft but doesn't embarrass itself either, sounding musical & punchy for it's 32w and there are many amps that fail miserably on Rock. Cranking it up a bit it keeps control well if the low spec limits it, sounding not grainy but a little splashy on high treble, if not too offensive. It'll be recapped & upgraded for a customer. Given our high spec upgrades to a certain level, it deserves an "Excellent" for the clean treble, solid midrange & extended bass. Of course for 32w it's a little limited to not clip out too easily, but we never expected it to be this decent when upgraded. It's not in the league of the best late 1960s gear but it delivers a quality enjoyable sound. On Rock it doesn't really have the midrange punch to do it as other amps can but at 32w you'd not expect it to, but it is clean sounding. On cranking it up a bit, treble needs one notch less to balance the sound which fills it out better. Trying it on the Tannoy Golds, it actually matches perfectly, suggesting for the clean sound that the design despite differentials, is still like the late 1960s designs. Compared to the UK Leak & Rogers amps that we say are good starter amps, this is your next step up. They aren't too hard to find either. BUY-RAW RATING: Good. COOL RATING: 6 smart looking amp if the sliders lessen the looks. (2012-16)


1972 Trio-Kenwood KA-6004 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 43w.
FC, DIFF. The fully complimentary follow up to the KA-6000 has a high quality fresh open sound that has potential to be upgraded out. FC here is the earliest we note, 43w is the 'both channels operating' at 1kHz rating into 8 ohm, 40w is the 20Hz-20kHz rating. 29v Clean output suggests 45-50w range. 1973-74 is more usual. Having had the KA-6000 again, the KA-6004 we have to say betters it in some ways if being about equal ranking overall. A very accurate rich sound with a fine deep bassline, probably the very last of the Classic Era amps before cost cutting & over-design took over. Nice looker if switch covers fragile, so we made a set for our 2015 ones. The switch covers you can make from alu pipes & rods like model train sellers have. As later than the KA-6000 there are things better & others less good, but still an amp of quality that sounds superior. The preamp-tone board looks very expensive, a double sided effort of quality, the Filter Boards under the cover are a bit untidy. The Power Amp is rather cramped, if it has improvements over the KA-6004 with FC power Amp, Relay & better Regulated Power supply. We did recap previous ones if this was early on to not yet decide an 'Upgraded' rating. REVISITED 2018. We've not had one of these for over 5 years if this is our third one now. To see one with all the plastic lever switch ends is a rarity & by the browned plug pins & attic looking grade dirt it didn't get used much so it's intact. Side cheeks are ply with thick wood effect vinyl & top lid off we forgot it had a cage inside covering the Power Amp, Phono & Filter Boards, the Phono has another shield. This was one of our earlier upgrades before getting deper into getting the best from amps so knowing how good the KA-6000 can upgrade, to try this again. Larger amp size than the KA-6000 with a very 1971-72 look with the line of lights, always a good looker & much nicer with the original lever switch parts. Power Supply main caps are 6800µf 50v x2 which is a very high value for 1972. The Power Amp is a small plug-in board, the same size as the KA-6000/TK-140X/KR-6160 one if it has large TO66 driver transistors, 2SA652 & 2SC1161, taking up a lot of space so the rest is tightly packed as is thre board track with solder on the tracks but no masking like later amps. The one on the Gallery shows the underneath Power supply has parts missing as it was likely damaged & repaired like that. Ours has the 'tooth' shaped 0.47 ohm resistors not the tubular ones so ours must be a later run one as those were also in the 1973 Sony TA-3200F updated version. Has a Relay for the Speakers underneath too, which is ahead of Sony if a 1971 JVC receiver had a relay also. Strange how it has untidy 18mm long pins on plug in board underneath that need trimming as that acts like a Tuner Capacitor & could bend to touch. Rear panel has 2x Phono, 2x Aux, Tuner, 2x Tape. Speakers are 2 pairs with Spring connectors for Bare Wire, plus the Pre Out-Main in and 4x AC outlets. Fuse only rated 1.5A. This was £115 to buy New in 1974, seems a bit underpriced as was the KA-6000. A bigger amp here that would have been a Serious Bit Of Kit in it's day as not many amps of this quality left by 1972. The bigger KA-8004 we look at on 'Other Amps' page. Bought as working, if fresh out of decades in the Attic, this is what you usually get on amps of this age. All Bulbs work. Looks-wise it reminds us of the 1970s UK Creda type electric cookers, very much a 1972 looking amp. First Play as just basic Serviced. Makes you wonder why people sell these amps, it sounds very decent, fast punchy sound with a clean sound and Bass is decent too. Not perfect in playing, the L channel is slighly quieter & tiny drop outs reveal it's 46 years age. So it needs work & we got it to compare to the Sony TA-1140 as that was another Five Year Absentee, so to do battle once upgraded. A second one we got before the other was finished & as original with minor servicing & appears a bit of an earlier one with the grey Power amp stage resistors & the odd minor difference. This has no Relay problems so we can play it more. Sounds convincing enough on Rock if focus on a Raw amp is rarely very good. Maybe we'll try this one As Original on the speakers to hear as near as a 1971 buyer would have heard. Design of the Amp is quite an update on the 1969 KA-6000, the KA-6004 has Differentials & Direct Coupling, plus Fully Complimentary Outputs which is early, 2SC1402 (6A 70w) & 2SA744 (8A 70w) which are well matched & seen in later amps. 2x Phono but both MM, no MC stage here. Phono x3 transistors for Mic & Phono, Tone is x2 with a similar design to earlier despite the double side track board that's awkward to work on, 2SC1345 in this amp aren't usually hissy. Then into Muting & Volume with Loudness. The Filters here are complex & to us Filters have no use, if one 'Low Pass' ie High filter board has a gain stage so the Pre Out is a more typical 1v level, the 'High Pass' Low Filter board has a buffer, why not make one neater board, instead of use two with many alterations? Low Filter has 1 transistor Amp stage then resistors in the signal which act like buffers rather than reduce the signal, much like the Sony STR-6120 does. High Filter has a Buffer Stage. To follow the Filter stages is a bit of a job, but if used with them Off they have no effect, the Low Pass filter has a Gain stage, this brings the Pre Out signal up from 100mV of the KA-6000 to the standard 1v as the Specs reveal, as the Tone is before Volume which very few amps do & we consider a better design & all with no NFB beyond the typical Tone stage. To understand it better on revisiting to see this is one of the better amps. Power amp with the Differentials & the NFB is more like later amps which takes good design to sound good. 8 transistors on the power amp plus 6 more for the Relay Circuit is what makes the Power Amp board cramped. The KA-6004 from a closer circuit gaze with the amp here does appear a better version of the KA-6000 & KR-6160 design. One Adjust pot is for Bias it appears. Low Pass Filter board is the 'High Filter' on the fascia so the High Pass Filter is 'Low Filter' as it filters the Low frequencies. It's confused many. Now Serviced which improved it reveals it sounds decent, unusual to have a reasonable Bass. Fast sounding amp if still a bit flat & not as focussed as upgraded amps for still being original though it sounds better than most. Will upgrade well is expected, if not always the outcome. But not able to try the first one on the Speakers after 10 mins use as DC offset is too high at 100mV & the serviced relay clicks on & off if comes back on erratically sometimes only one channel with tapping. 1972 amp fresh out of the Attic needs a recap as it could damage speakers or damage itself further. For us not a problem but for one who could buy it to use, well you see the issues here. The Second one is better as 'Raw' so to Service & then try on the Speakers if it's reliable, to hear what a 1972 buyer would have heard. Now All Recapped plus many new transistors to lose some hiss, to find a few caps were physically bad, capacitor leads rusted off on a few is not typical on this amp as we've had 4 of them, but the amp is 46 years old. Relay Problems sorted too. It reminds of the KA-6000 at the same level, it could be upgraded a lot more as the KA-6004 can, but it has a Fast Sound with Wide Stereo and Good Bass. Detail is clean with a quality that shows it certainly is a good one. On Rock Guitar it plays it convincingly which not all amps by the 1970s can do. It's worthy of an Excellent if could improve further if that's beyond the scope of Upgrading to sell at an affordable Price, but we do this for our own interest too, try to bring the best out from some amps. Compare to the KR-6340 as that's a 1973 4ch receiver. Before Upgrading the KR-6340 more. A similar sound balance, not quite as Bassy with the KR-6340. Focus is the same, not as smooth as some earlier amps on either. Earlier the same day we had played Vinyl on the LX33. Verdict Compared to the KA-6000. Really not so different, later design without Capacitor Coupling & Regulator for preamp. The KA-6004 is still a bit of a sleeper if the ones we had a few years back sold quickly as it's a quality amp & would upgrade further, if we keep our KA-6000 still. 2019 opinion after the 2018 one & upgrading the KR-6340 further. The KA-6004 isn't unlike the KR-6340 in several ways. KR-6340 is bridgeable to 50w+ which reads clean sinewave like a 90w amp, if would need upgrading a lot. KA-6004 is 43w if ranks amid 50w amps. KA-6004 has a relay as does the KR-6340 so a little more security on speakers than direct coupled ones without a relay. KA-6004 has spring connectors for Speakers. Those 2 filter boards with much design changed may work fine, but lack a little class. 2020 UPDATE. Back on it again, the 4th one we've had for sale a while if to see ebay ones recapped but not Upgraded & Raw ones offered at £500+ is overpriced. The KA-6004 looks more familiar now from the 4ch KR-6340 & KR-8340, to see the Build Quality of the 4ch started here. Oddly never a KA-6002 probably as the change to Differentials outdated a prototype? KA-6004 is a very well made amp, the Filter Boards still messy with empty spaces, couldn't they have made One Neat Board. But It Is What It Is & about time we Upgraded this one more. We Rated it 'Excellent' as Upgraded to a Selling Point, if playing now it's a bit lacking & barely scrapes an Excellent to be fair, if a few amps have Upped The Quality since. Focus is a bit soft, the Resolution quite away from what we got with the KR-6340. As original it's not too interesting, if the design is worth going a lot further with based on 6000 & 6340 ideas. The 3rd one that sold fast had more Upgraded to try, if this one will go further. The 4th one here with decent fascia & side panels plus all the lever switches intact is hard to find. Slight corrosion inside isn't unusual with open grille amps if it's been forgotten here until considering the KA-6000, if it can clean up more & repaint neater. Got tired of the KA-6000 now & wanting to overdo it decided against, so try the next one they made. Easily 50w upgraded so worthwhile. Big Size Amp looks good on the table too. Think we underestimated this one for it being an easy find once, if they aren't now. Having 200+ amps now since this one was 'No 60' on our Early Pages, to see it differently now over 140 amps later. BUY-RAW RATING: Good. COOL RATING: 7 smart looking in high grade if plastic wrap side cheeks & the fragile switch levers are hard to get perfect. (2013-2020)


1972 Trio-Kenwood KA-4002a amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 18w.
CC. Well that's how it goes, not had a lower power Trio in years then two come along. Appears this Trio KA-4002 is the one we first got in 2011 to start the interest in Vintage Hifi, we wondered which after hearing the modest small sound of the KA-2002, but to know the 4002 was the one now makes sense, it does sound very decent for 18w. This is the uprated 18w version of the 13w KA-2002(a) that internally is much the same amp if it has TO66 output transistors, not the 15w rated TO220 ones on the KA-2002, this has 2SD155 25w ones to give extra headroom, if there are obviously other changes, the KA-2002 42v HT is now 52v (on a 50v cap). The KA-4002a styling adds an extra rotary control for A&B speakers plus 2 extra push buttonsfor Lo & Hi Filter as they label them, if Filters can sometimes be too complex plus asdds a front 'Tape Dubbing' 6.3mm jack. Silver Aluminium control knobs & silver push buttons instead of black looks more 1972. The transformer is bigger for the 13w to 18w upgrade, 66mm length now 90mm, looking more like a 50w transformer. Case is still the same size. Rear panel adds an extra speaker pair if unusually the Main Fuse is 2A on the KA-2002 but only 1A on the KA-4002A. But 60w (60VA) rated KA-2002 to 115w (115VA) rating to the KA-4002A, which also adds 'Mono Out'. From the uprating & transformer size plus VA rating, the 18w of the KA-4002a suggests it's a modest 18w. The back panel info plate is screwed on & under it as suggested by printing borders, it shows 'Kenwood' instead of the UK-EU 'Trio' branding. After Servicing & a bit of a run-in, to hear what it sounds like. The KA-2002 was a little thin sounding as it was kept tamed for the 15w output transistors, the KA-4002a is a fuller sounding amp, a punchier sound that gives Rock guitar some weight. This is still the 1967 design style as on earlier Trio if by 1972 it was 'out of date', Trio still used this design further into the 1970s, as why give up a good design. It still sounds aged & a bit blurry, with deep bass limited as typical, but overall the sound is more pleasing than the KA-2002 as original. To compare aged KA-4002a to recapped-upgraded KA-2002. Quite a difference here, the KA-2002 sounds quite small in dynamics to not overdo the small output transistors. Both have that classic early Trio fresh sound though. The KA-2002 is got used to again & still puts out a nice sound, but it is a smaller soundstage that does struggle with fast transients blurring them off. But not everyone wants to Rock The House & the KA-2002 has given it's owner many years of pleasure & for our recap-upgrade they'll enjoy it more. Back to the KA-4002a & the bigger more dynamic open sound with crisper focus is the difference. The KA-2002 is fine if you don't want a loud amp, but the KA-4002a has the sound heard more in higher power amps, even as original. Once Recapped. With upgrades it sounds smoother with a better bass without having the extra high treble & deepest bass of higher power amps. The early Trio-Kenwoods are always good sounding if some need more upgrading than others, the good honest Trio sound. On our Tannoy speakers it sounds good & gives enough volume at 18w to fill the room on 95dB speakers, if it'll not go much louder without flattening off. We've considered 18w to be the starting power for Hifi with other 18w amps & this confirms it too. We didn't try it from the Pre Out to a higher power amp as we've found before the sound will still be an 18w one to not clip. Next when Biased to our usual way it makes the amp sound fresher than the original setting that had it run a little warm. An oddity on this is 2 sets of Speakers, select A/B for each, but if connecting 2 sets it only works with 2 sets as it does them in series, so it'll be silent on A&B with one speaker set attached. Running 2 speaker sets on 18w a little optimistic, if this stops overloading. BUY-RAW RATING: Grille lets in the dust, but upgrades well. COOL RATING: 7 with the wood effect side panels this is a cute amp, betters the earlier 4002 look from the 1971 range. (2011-18)

1972 Trio-Kenwood KR-6200 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 50w.
Semi Complimentary, Relay, Differential. One to buy knowing the KR-5200 was a Quality one & to see it's a step-up in quality on seeing it. Not in the HFYBs if the KR-5200 is & KR-7200 at £192 +VAT, maybe the KR-6200 wasn't a UK model? The Brochure on HFE shows the inside top build. a step up from the Tatty Build of the KA-6004 if this is Semi Complimentary, not Fully Complimentary as 4x NPN outputs. Shows they had more than one design team on the go. It's Sad that amps like this get abandoned in the attic for the 'aged' grade if it'll clean up nicely. It seems the Tuner cord post with the wheel on broke & the cord stayed put, the wheel & screw seemingly long gone as not inside if could have slipped out for the case-lid gap, but later they turn up after much moving it about. The post has the screw bit looking like an old break, which explains why it got abandoned. Build Quality is very high here, the KR-5200 for a Third Model KR-7200, KR-6200, KR-5200 etc is better than a 30w 1972 receiver should be, based on the KA-6004 tatty build. After this Quality, they made some decent looking amps continuing on from the build stye, if by 1974 the IC was used which puts us off them & soon even IC output blocks. Trio-Kenwood best from the TK-140X in 1967 to this in 1972, just Five Years. Notice it has Seven Fuses which is a move on from earlier years, one on the outer rear case, 4 underneath plus 2 more on what looks like the Output 0.47 ohm board & then the Relay. This is a huge move ahead of how other Direct Coupled Amps are, some Sony just had One Fuse & a hopeless 'Protection Stage'. We aren't so keen on these to use on Speakers, nothing to save you from up to 50v DC on the speakers. Power Amp Board is like the KA-6004 one, a plug-in upright board with 4x TO-66 driver transistors, we thought the KA-6004 one was a decent one & to have similar here may get this kept, it's a Good Looking Receiver too. As put on the Blog, this was bought knowing it needed repairs & the tuner cord issue found too. Speaker part fixed easily, only for having a Spare. What's Different KR-6200 to KR-7200? Not much, front panel adds a Mic Volume control. 45w (50w) to 55w (60w) with ±44v or ±48v HT, looks much the same inside. Adds an extra Phono input to the same Phono stage. Tone to Volume [to a 20dB Gain amp-this is a circuit error, not in the amp] then Pre Out then Main amp on KR-6200. Tone to Volume then Pre Out then Main Amp on the KR-7200. A different way on the KR-7200 adds the 20dB type amp on the Input such as Aux, it's on the later part of the Mic Board [or is it?]. The KR-6200 Tuner MPX board goes to the Inputs board, the Aux supposedly goes to the 'Tuner' setting on the Phono-Mic board which is an odd design, but what it is, or is it? The Tone Boards the same on Both, not taking in the extra KR-7200 gain, so which is best? But the KR-6200 HFE Circuits Are BOTH Wrong. It made No Sense, so as with everything, to Question it. Left 'Aux 1' goes to Pin A4 on the Push Buttons board & Out at A5 with no resistor. The 'B' numbering being the R channel one. A5 to the Input Selector, to 'Rec Out' direct, to S2 'Mode' switch. Both versions are wrong, one adds a 20dB board that's not in the amp. Careful what you believe is right. Mode back to the buttons board & via three resistors it goes to the Tone. More Wrongness, but only their Manual errors, not the amp itself. Can only assume they updated the design & did a newer Schematic. Looking for the X00-1240-10 board, a Power Supply with Zener Diodes, where is it? The one fitted is a X00-1250-10 without the listed Zeners, same 1A-2A fuses and other Rectifier Diodes. It has other Zener 1S338 a 15v one as D6-D7 on Q3-Q4. No Manual shows this. There is no X13-1380-00 20dB amp board. There is a X13-1250-10 board with 4x 4A fuses not shown in the Manual photos underneath. Both KR-6200-KR-7200 top inside photos show the later X00-1250-10 board showing someone messed up putting an old Schematic in both. The extra X13-1250-10 a later Power Supply-related change like the other 1250 board. It goes to the Relay so must be an Improved Relay stage. The power supply board in the manuals is not the one shown, the double 330µf cap isn't joined, it's two seperate uses. Why it uses a Double Cap in one can is as illogical as showing a board layout for an earlier version yet the later model humbers. Unknown Bits. On our one, underneath on the right a small board with 4 20mm fuses plus a few components. This is mentioned above. Now to see another, by the Mode switch a tag board with a '154' capacitor & a 680K resistor. This seems to be an audio part as it's doubled for Stereo. Four wires, two go to the top front right Tuner board so it's from that, rather than an overall Bass filter. Once Understood. The Receiver is the Last of The Non-IC Trio-Kenwoods, beyond the KR-7200 in the Same Range. Sadly Trio went to ICs more & more, even impressive ones 1973-75 are with ICs. So this 1972 range is probably the Last We'd try which is a pity as the 1963-72 Trio Range has some good ones including this. On Speakers this suited our Tannoys well, we've found Amps with a Midrange Control suit -2 on Midrange Control. Surprisingly Lively on Speakers, we briefly tried it when it was still Original, it has a very Clean Precise Sound that Got Us Playing it on TV Sound longer than trying other recent Amps. Considering this is the Last Range of No-IC Trios, perhaps one to keep after playing it more & the next day. Hearing it Sound So Good makes it look Better in that Strange Way Hifi Can. BUY-RAW RATING: Ours still Worked, if generally 1972 is past their best. COOL RATING: 7 Smart Looking Midprice Styled Amp. (2023)

1972 Trio-Kenwood KR-5200 receiver ↑
AS-ORIGINAL (Once Serviced): --. UPGRADED: --. 30w.
Semi Complimentary, Relay. This Receiver is more like the 1973 4ch KR-6340 build style. An updated quality showing Trio improving from how crude the 1965-67 ones were, if by 1975 all Brands got cost cut. For a 1973 range, these didn't sell well for UK's issues at the time, so never found one at a reasonable price. KR-7200 is the 55w top range one. On seeing this one here to see the Quality was still here. But this Amp was a £30 buy with no Top Cover or Base Cover & no Feet even. Looks like it was built into a cabinet as no sign of screw marks, silly idea by 1972-73. Looked a bit sad but worth having for Spares & Ideas, if it's a Good Amp worth a try at least. Seller said 'Untested' as if anyone without Hifi knowledge would try it, the big cut in the cable pretending they never tried it if the Relay shows someone scraped the board so has tried it. No Fuses blown if Damp Stored & Cobwebs, if the 'Mud' on the TX & main caps seems to be not Flood Damage but a bit wet briefly muddied the dust, someone kept it over 40 years. With No Covers the chance of finding them at £100+ to get here if USA sellers have parts sort of outprices it. The Build of the KR-6340 showed a big step up for Trio-Kenwood, no more the rather Crude Power Supply drop Resistors & the KA-6004 showed similar. Here they still use a few 1960s parts if a Relay as the KA-6004 has. Better looking than the KR-6160 we've had. Circuits. Still has a design like the 1969 era ones, here updated to Differentials, Relay & no Output Capacitors as the 1971 KA-6004 has. This has the TO3 outputs still, 2SC1111 50w 6A for 30w is decent. Later Amps with TO-220 regulator style Outputs ones mark a dip in quality we've found, based on the rest of the Amp being Cost Cut. Design is high quality, one Bias Adjust as Differential amps were never Autobias like the Capacitor Coupled TK-140XII & KR-6160 amp boards. The Strange thing with Trio at this time are push in boards using very long cable pins, this creates a FM Receiver in effect & they leave them too long which could easily touch. The one for the Front push buttons has all those pins so close. Tone stage is a Rare Passive design, seems some Brands used Passive & Baxandall with Passive beng on the lower model, if Passive is based on the 1966 Sansui TR-707A design & sounds great, if depends on design. What To Do With It? The Amp itself would clean up well & beyond a few control knob scuffs it is High Grade beyond the light 'weathering' from being stored open in a Loft, Shed or Garage. Service it up a bit & try it. A later idea before it arrived was to use it's parts elsewhere if now not so sure as the amp deserves a try. Someone could build a box cabinet for it easily enough so to see what it's like. Fix the Cable cut by neat splicing, not to fully rewire yet, tatty plug badly wired could be a cause of Faulty? All 3 Fuses good, so plug it in. What Does It Do? No Disasters, a bit of Crackle if Plays Both Channels on Aux. Amazingly it sounds Nice, a bit Ropey with Noises & Crackles but can try it, if not to trust for long. It'd get Rebuilt like any amp so doesn't matter if it's Tired in Use. Bought as Spares but 'Regret the Bargain' as it's better than expected if missing Casework. To Part a Working one only needing a Rebuild is hard, but the costs & sell to keep it alive would be a minus. Parting Is Such Sweet Sorrow, so let it sit a while, it helped the KR-6200 above. Give it a clean to see it's otherwise sellable grade unlike a few failures recently. This would Upgrade & Recap into a very nice amp, if without the covers. BUY-RAW RATING: --. COOL RATING: --. (2020)


1973 Armstrong 625 receiver ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: n/a. 40w.
CC. Cheaply made with bad power supply capacitors & plastic bases, it actually sounded better than average, but for how badly made it is in certain areas we'll not rate it more than this. In 1973 the 525 matched the B+O Beomaster 4000 in basic spec at £110 vs £193 of the B+O. The big capacitors are explosions waiting to happen if not blown already, best to avoid this brand. Did we say Armstrong Are The Worst Hifi Brand Ever? They've been around since 1929 remarkably. Don't waste your money on their earlier ones, see the 1966 & 1968 ones... We hear a very late 1970s Armstrong newer model made just before they closed is good, but no details findable & nothing on the HFE site though circuits are findable on one site. Armstrong on their 400 & 500 range used obsolete Germanium transistors, buying up unwanted stock cheap & were still selling the 500 range until this 600 range arrived. That is The Biggest Hifi Swindle ever. Read their ads in the 1972 HFYB & they have the cheek to say their awful 500 range is better than anything else. The remarkable BS hype of the 600 range in the 1976 HFYB ad gives the idea the range is the 'best ever made' in the sort of gushing hype that surely would be illegal now. The amp is cheaply made with no quality in construction, messy wiring with low TV grade components. The Goodmans UK receivers were a far better buy at this time. This sort of false hype gives British Hifi a bad name... Not one we'd want to buy again as full upgrades would not get a buyer as these are budget buys today. To be fair to it, the cheap construction apart, it could upgrade to a better rating, but not for us. 2019 Opinion on 'Armstrong'. We see these as the first 'Disposable' brand, the Quality of the 400 & 500 series is a Disgrace, the components & build quality is very poor, but these were sold Cheaply when new & were hyped up in adverts. Sometimes ebayers pay over £100 to regret it as the aged lofi Germaniums have aged on the often-found 500 series. The 600 series of various amp & tuner combinations is still Cheaply Made British Junk, the same sort of awful quality of British Leyland Cars. Mass Market gear that seems good but is best avoided. The 625/626 receiver is poorly made with no Ground Shielding Metal case at all, plastic base & wood top. Horrible to use as inputs fade in & out. Some will champion these as UK brands like the Goodmans receivers. We tried to upgrade a Goodmans Module 80 as Reviewed, it just showed up how lousy the design was. Don't Waste Your Money buying Armstrong. The Leak Delta/Stereo 30/70 as British Hifi are good starter amps, but avoid Armstrong & we never want to see one again, horrible things. BUY-RAW RATING: Risky as the main capacitor is usually bad, else not so bad if the casework is intact, but it's budget gear once sold with dodgy hype. COOL RATING: 5 the piano key switches add some style if it'd be below average otherwise. (2012)


1973 Heathkit AR-1500 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 60w.
SC, Diff. Heathkit best known to UK buyers for the 1959 valve Heathkit S99, see the other amps page. Their transistor kits are much harder to find in the UK & this is the 1973 version of the 1967 50w Heathkit AR-15 and in 1974 was the (same?) Heathkit AR-1500A 60w, then the digital tuner AR-1515. No earlier than 1973 as no Heathkit UK ads show it even by Mar 1974. The AR-1500 first appears in the 1974 HFYB for £191 as a kit & with the wood case, if £252 by 1976 as likely the 1500A, £302 by 1977 then Heathkit vanished to return with just one in 1979. USA ad says $457.90 inc the wood top lid. To build a simple amp is quite a job, having had a S99, but a receiver is much more complex. Rear markings suggest Multivoltage which the amp isn't if the UK one has 3 core mains & USA the typical 2 core to help identify. Heath Daystrom were a USA company & in the 1960s the Hifi News ads show they had a London showroom & must have done well with their high quality kits, but as the Discount Stores & complexity grew, this was way beyond the majority of buyers to build. Maplin took on the kits market by the 1990s with Velleman kits, if long gone. In 1968 Knight-Kit were offering even more adventurous kits, see the Amplifiers list page. But the AR-1500 is a good looking receiver with different styling to the 1967 AR-15, with all transistors in audio stages. All Phono socket inputs & 4mm posts for speakers, this looks an impressive amp, the brand is rated online by USA owners & the AK site has the schematic. The quality of the amp seeing it first time is very impressive, 17kg amp 47cm x 34cm x 14cm & a heavy cast fascia with a medium-dark walnut veneer case, a very classy looking amp indeed. Wood lid off reveals a full metal case, like the Fisher early amps, unlike other main brand amps that are just an unshielded wood top. Inside the boards look of high quality, a 1967 feel to things as it's based on the 1967 AR-15 & the board are edge plug in types that have the socket on a pivot so to aid testing. Quite a few axial caps in here that don't age well & the MW antenna needs pulling out fully to get to the input & speaker sockets & doesn't fold away with cables connected which may limit space. A pitch coated huge transformer too, nothing cost cut here. All the inputs have adjust pots like McIntosh preamps so there is a lot to service. The power amp board unplugs making it easy to work on to build or repair, the 70v axial caps are all equally old leak-crusty just a bit, but on cutting open they are still good, a production error probably. No bias adjust pot on this amp, as the 1966 Coral had, but it measured fine. The sizeable cast iron heatsink & solid metal control knobs shows how well made this amp is, we are impressed with how logical it all is with the plug in boards, so nice to work on with no wires hanging off them. The only less easy part is the 2 front control boards, 3 of the front switch covers need removing to free. The small control by the Headphone is a FM Squelch control. Semi complimentary design with 9 transistors on the power amp. Power supply is 70v-75v axials if no leaks here. The inputs board has a similar input stage to the B+O 4400 with a PP buffer stage. Our one looks so professionally built it might have been a ready-made one as there was the option as this is advanced work to do, if they wired the headphone socket round the wrong way. Scope out V/H is part of the construction testing features as are the bulldog clip wires on the transformer. So it looks like McIntosh in some ways & also like the early transistor Fisher amp, two of USA's top Hifi brands. The looks & solid build quality leave many amps behind. Trying it, the sound improves with use as long sleeping, a clean strong kicking sound is here. Rock sounds accurate to rate it highly, if not a bassy sounding amp as is typical of differential amps. Matches well to the Tannoy Golds if perhaps not a perfect match as original, certainly a good match. After recapping, it brought the treble out quite a lot more, leaving it a bit rough sounding, but it can be improved. Using Tone Flat does make a noticeable difference, even after upgrading. The 6000µf original capacitors we've left in as spec is good still, if getting the amp back in 2017 these smelt stale so we replaced them which is tricky as non standard size. The clean honest, if unsophisticated original sound of this amp is prime for upgrading into a great sounding amp. After playing the JVC amps & Duette germaniums since last trying this, the Heathkit reveals itself to better others with it's pleasing sound. To the point we'll keep it longer & do more as this great looking amp has let other less neutral amps put it away. Despite hours of trying testing & recapping, the Tuner working eludes us again, it's very difficult without a service manual & proper tuner test gear. BUY-RAW RATING: This is a home constructed kit by an unknown user, unless you get a Factory made one as was the option, but generally these survive as they were a success. Some were sold ready-made. COOL RATING: 9 the styling here is Very Good, chrome plated cast fascia, green lights & a walnut wood case, looks as classy as McIntosh gear, Underrated. (2015-17)


1973 JVC 4VN-990 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 2x 88w -or- 4x 35w.
4Ch, Bridged, FC, not Diff. JVC kept a quality until the 1976 JR-S-600 below, quirky looks but still That Good Sound, if by 1978 JVC went Budget Brand with ICs yet sold better than ever for it. This is a 4 Channel amplifier with that Bridged Output Stage to make a powerful 2 Channel amp. Our Sept 2019 Blogs looking at 4Ch amps we could use found this an interesting one. Marantz ones may go slightly Higher Power if sellers asking £1000+ is ridiculous, do they not understand a 47 year old 4ch amp has been abandoned since 1976 & they are always very tired. Marantz 4400 with Oscilloscope, ±41v. Build Quality for 1973 is Way Ahead, to think it's like 'Ideal' 1986 High End, but No ICs & cheaply made by then, but not in 1973, just Plug In Boards that have all the Circuitry easily accessible, not tightly wired boards as is The Usual. The Wiring is Extremely Good, a few Unshielded Cables in Audio to the EQ if this Amp is a Delight for the Tech & Upfgrader. Fully Complimentary TO3 outputs early for 1973. It sounds awesome Too. JVC's Best for Sure. The 4ch Balance joystick seems to be an optional extra, if no 2ch balance either. Some brands included the unit or built it into the amp. 4VN880 has a silver cover over the balance plug to confirm. Twice Tried. Had two of these JVCs, the first not the grade to do our work on so got a better one for a low offer as Blogged Mar 2020. So we have a very nice one now & the inside controls panel cover it lacked. This Amp is a Joy inside for The Tech, all the Amplifier boards are Plug In with screw-down bars to keep in place. Power Amps are on the L&R sides if all accessible. The Underneath is very neatly wired with all far from JVC chaos, this is a very well designed amp. The Boards are numbered & a diagram on the inside cover. JVC early amps are a very decent design, look how many JVC we've had as the sound was often better than similar brands. The Fascia is very smart with touches that give it a Mid 1980s-Mid 1990s High End look. Still has the JVC SEA Graphic EQ if this is still Passive & no problem to use, nothing like Cheap IC EQs, this is 'Hifi'. Five rotaries for the EQ better than the sliders. it just looks like How Hifi by the 1980s became, large Volume control on the right, grippable Selector controls of a good size. Needle Meters for 4ch with level controls to match your source level audibly & a Push Button Power Switch that is still better than Levers or Rotaries. This has a Flap covering 2x Headphones, Meter, Speakers, Balance by 4ch Remote if no Balance on the amp oddly, 4ch Rev for altering, Filters, Tapes, SEA for Front & Rear & Loudness simiarly. No Wood Case if this looks very classy. The 2ch Amp version is the 50w VN-900 similar looks if a lesser beast. Rear Panel is all Phono inputs wth DIN for 2ch Tape. 2x Phono with 33-47-100K loading option on one plus Gnd, Aux 1&2, 4ch Tape, 4ch Line Input. Pre Out-Main In via the 1967 styled thin Phono plug wires, these do get lost if later amps put a Switch instead to Link. 2-Spk-4-Spk ie 'BTL Bridging Mode' switch over the Multivoltage block, 2 AC outlets & Speakers to run 4 Speakers for 4ch, but only one set which is wiser for Bridged. Ch1+2 for 2ch mode. Strong speaker springs if the Tab is still Live & they are fairly close. Quality Build here & that later 'High End' look, they as in later designers had to copy it from somewhere, this is the Amp it seems. Inside Top. This as we've said is a Drooler's Delight. Those 13 Plug In Boards, big encased Transformer like Sony used on pre 1971, certainly a Sony TA-2000F look here, very smart. Three big capacitors, 2 are 6800µf for the HT, plus another 1000µf 80v. The unusual item by the capacitors with square metal wired pieces is the Power Supply Diodes, it looks like a 1930s Selenium Rectifier seen in big Radios, if is Silicons. What a Fantastic amp, it has to be said, this is so pleasing to see such quality in 1973 still. The front casing covers the passive switching, all very neatly done. The top lid is a heavy solid piece, far from those bendy tinny things. There are really very few amps pre 1974 of this Build Quality. It's a Nice Design & for it being on Plug-In Boards, so much easier to work on, why we got the Amp if not aware how well built. Underneath. Surprisingly small feet on the heavy base panel, again that High End quality. Even the base screws look like 1990s Marantz ones. Base plate weighs 1.8kg as 2mm steel. Lots of neat wiring with the long pins on the Plug-Ins with the wrapped wires, sometimes 2 wires. Nothing else as all the boards up top. Quality again. Marantz isn't this Quality. As with the Trio-Kenwood KR-6340 & KR-8340 the wiring for 4ch has to be busy, the 1973 Marantz 4070 4ch amp wasn't the quality. The £900 new in 1977 Marantz 2385 similar. Circuits. The Service manual says this is 16kg, again the Quality. 4x 35w at 8 ohm, 2x 88w at 8 ohm. Based on other Bridged Amps, 88w is a modest rating. There are a lot of Blank Spaces on the Boards if 4VN-990 is their top model & their top Receiver 4VR-5456 is very different. Those hissy 2SC458 were very noisy on the first one, if our one isn't if shows other aging. Phono x3 transistors, the design looks more advanced, as in 6 CR items on the EQ stage. Various switches then a 250K Volume control. Pre is x2 transistors with NFB. The SEA is the standard SEA if the schematic misses scanning this fully. Pre Out-Main in connectors, if yours misses those connecting wires it'll not work. S15 & S16 are Filters quite like the Akai AA-8500 type with not much loss on these plus x1 Transistor. Main In usually goes to the Power Amp direct. Power Amp with Bridging Stages on two, then Differential with Balancing adjust that not many amps give, Bias stage with adjust, decent Power amp with proper TO3 output transistors & output via a Relay. 22K of NFB typical for the era. Meters on the Output with Level Adjusts. Power Supply on the 3 big capacitors , 2 for ±38v is way ahead of ±27v & ±31v of the KR-6340-8340. Marantz 4400 with Oscilloscope and 100w bridged, ±41v. The 1000µf 80v actually is on 44.4v as the Preamp supply. Power Amp Outputs are NPN/PNP Fully Complimentary pair, advanced for 1973 & 80w 2SC898 & 2SA758 are Quality spec unlike other 4ch Receivers with smaller size cased Outputs. What's The Sound Like As Original? We tried it when we got it a while ago & could hear the Quality is in there for Upgrades. Relay on fast if it's a working one. Volume control is with subtle indents if not stepped thankfully. SEA button is 'out' for use, gain is clean showing a non grainy design as JVC is at this era. Amp only part serviced & sometimes not fully stable, but it's to be Rebuilt. Clean Punchy Fast sound, Bass sounds decent for Original, playing Reggae. Onto the JJ Rock tracks it reveals why we upgrade these amps if is still decent with +5 on 40Hz SEA. Lacks the Finesse of Upgraded amps as you'd expect if it's still enjoyable. We've found this with the 1970-76 JVC too, the 1967-69 ones need more help. Wide Stereo with a Smooth midrange. Runs Cool on the TO3s. How did people put an amp this good away to go rusty like the first? SFCS level does nothing on 2ch. We don't do --/10 ratings, if this amp gets a lot of 10/10s in several categories. World Class Amp in Build & Sound for 1973. That's with 2ch Bridged mode, shows little use to sound that good. On 4ch mode, not quite the power at 38w, testing on Headphones until it'd be Trusted to try speakers. we're playing 100w Sony pair TA-2000F & TA-3200F hugely upgraded, yet this amp as Original displays the quality it took Ages to get with the Sonys. The last Transistor Amp we played on Headphones was the rebuilt 1966 Sansui TR-707A, the 4VN-990 is a more Fresh sound if really not so different beyond upgrades. Any Minuses? The black paint is a little thin & can rust. The baseplate is untreated so goes white on whatever plating they used & can rust as the first one showed. Still Single Insulated 2-core mains, you really need 3-Core earthed on amps without Turntable to Ground. Upgrading. As Awesome as this Sounds as Original, we can hear the weaknesses, they do show but the amp is such a great one, to Improve the Sound in our way will make this. Up louder it starts to break up in that 'Pioneer 1976' way as most amps do have. It has one medium NFB stage as is typical JVC if this sounds fine so far, if more upgrading will tell. 4ch Amp means Double the Circuitry & Switching, so a Double job on all really, if one Power Supply. Try On Speakers as Original. We hoped to, if DC offset on the L ch was 400mV & wouldn't adjust to normal so needs work. We like to hear what Amps sound as Original, to see what the 1973 buyer would hear, but not to Trust in this case & many other times. Yet people will just plug it in & try unaware of issues like 400mV DC offset, not dangerous, may reduce with Speaker load or maybe not. Why Risk Good Speakers or a Good Amp? A Permanent DC Voltage is on always, 400mV is fairly low perhaps, based on the value to Trip A Relay, but it's got a Fault, but what happens next if you just Blindly use it? To Upgrade. Boards are slightly scary as they can plug in either way & to put a board in the wrong slot. Take note of the Sticker on the Inside front cover for Board Numbering as well as 'Parts Side' to not plug it in 180° incorrectly. To Learn & Mark them clearer, one is marked with 2 different numbers. Power Amps Done. Done this first as DC offset was way off if now correct. Very Decent sounding amp, the last amp we played was the 1966 Pioneer ER420, this is in that League of Sound Quality. Some amps just do Sound Better than others as near Original. Here the DC offset was bad, 47 year old amp will always need work, if some will still Plug & Play, here DC offset was fairly high. Other Boards. Thirteen Boards, the Inside Sticker & Manual describes them. The Power Supply board nearest to the Transformer TAP 173 if no markings on ours. A Regulated Power Supply for 5 voltages. Adjust Pots on Speaker outs? TAC 250 board right on the Speaker Outputs is a little odd. What Is It? For the Front Meters, ours not quite balanced so they just adjust the Meter Level. no effect on sound. The Main Diodes. This is a Steampunk looking thing with Heatsink Fins, CD2P-B4/1 looking a bit like the Yamaha CR-2020 Schotkky Diodes. No info anywhere, 1973 quirky item. Bridge Rectifier. 2A or 4A by the numbers, or could be a 10A or 800v unit for the size & fins. Designer Flair as the Amp is the Highest Quality by JVC ever. Rebuilt All 13 Boards if not got the Right Power Capacitors yet, don't want Multipin ones, not mentioned on buying, if there is no choice buying. As the Above says, this is an Awesome Amp, imagine it Rebuilt & Upgraded. Very Precise & Solid Sound with Tight Bass. On Headphones test only so far. This Amp has A Sound that is Rarely Heard in Amplifier. Hard to Put into Words, the Resolution is Very High with Detail & Focus How It Should Be. The Amp has NFB in two stages if it's not so unlike the 1969 Pioneer SX-2500, another amp we're currently doing. Very Fast Amp if dare we say a little more Musical than the SX-2500 currently is. Rock is Super Clean if without the Three Main Caps done, it could do with a bit more Weight, if is So Well Defined with no Confusion or Slurring of Fast Loud sections. The Jam 'Start' reveals the Speed in this amp, if don't forget we're Rating Our Upgrade too. SEA in or out really no difference, if it was noticeable before. Certainly an Amp for Detail Freaks to 'Hear It All'. To get the Big Bass sound takes more Upgrades. The nearest Amp beyond the Sony Pair is the 61w Marantz 1122DC, comparing those two will be interesting. This JVC amp has always impressed. Biasing. The Manual isn't in English well. Two Adjust Pots per 'Ch', the Edge one is DC Offset read at Speaker outputs. Mid one is Bias set via the two large white resistor top wires. Set in 4ch mode only. Check DC offset again. Brings a final Finesse. 1973 JVC with 88w Min in Bridged Mode. Speaker Modes. 4ch as expected, for 2ch you wire it differently. Not labelled on the amp, so no sound is confusing. some Bridged amps like the Marantz & Trio-Kenwood alter the speaker outputs on a rotary, JVC only alters the Bridging mode on the basic switch. They Sold It To Us Like That? For not trying on Speakers for DC Offset issues, to find the Amp actually has no Output to Speakers. Another ebay con & to solve took a lot of work searching. Further issues caused a lot of difficulty in solving. If this was a customer's amp you'd just have to fix it as that's the job. The Front Meters. The Bulb will go on these, if the otherwise detailed Manual says nothing. These are designed to infuriate it seems, if look inside, the meters frame has 2 screws undone to take the unit away. The tiny tubular 20mm bulbs inside, the 1984 Technics SU-V707 had similar on the front display as does the 1970 Akai AA-8500... "12v 55mA axial bulbs" are what we got. Still got some & they're the right size. But the manual says 6.3v 44mA, not so easy. Bulbs will fail again so a better solution needed. It is possible with 29mm LED bulbs & a different voltage supply, we got ours done. The SEA Isn't As Quiet As Other JVC. The 1kHz control brings up a Noise Background that with it's 12dB Gain makes a Quiet amp a Noisy One. Other Noise Issues we solved if very tricky. To solve the SEA noise with a lot of Unshielded wire to the SEA controls is the issue. BUY-RAW RATING: 4ch amps usually ignored since 1976, care needed. COOL RATING: 8 looks the part, oddly late 1980s looking. (2020-2022-2023)


1973 JVC 4VN-880 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Not Possible. 2x 55w -or- 4x 25w.
4Ch, Bridged, FC, not Diff. The next one to the mighty 4VN-990 as reviewed above. This a 12kg version of the 16kg 4VN-990 a smaller size without the heavy casework. Attractive item with the 4 needle meters, this is quality item. Two others in the range a 550 & 770 are 4x 12.5w if 30w or 25w x2, suggesting one was an earlier model. The 880, 770 & 550 have Standard NFB Tone Controls, usually JVC are with their SEA Graphic EQ which works well, if as the 990 shows to do 4ch of that is quite a lot of circuitry. As with the 990 a front panel socket for an optional Balance joystick, if even with 2ch balance is rarely used. Inside Top has 8 of the Plug in boards, the 990 has 13, the same finned Rectifier block & 3 main capacitors. The Tone-Pre is on one double sided fixed board. The Power Amp heatsinks have proper TO3 2SA756 and 2SC1030 fully complimentary outputs with 4x 30mm fuses on the power amp HT supply lines. Boards with those Hissy small transistors that need all replacing, by 1973 Yamaha had moved on to different ones, 1973 JVC the last amps with these. Rear panel much like the 4VN-990 one speaker set, the same type of 2ch-4ch slider if the Multivoltage block inside now. An 18Hz filter is 'S8' Subsonic filter on the 4 Power Amp inputs. Multivoltage still at 220v as German 1988 tech stickers tell it's origin, someone cared about it to get it repaired. Underneath is all the wires connecting, shielded audio cables & the same 990 quality. Still the 2 core single insulated Mains cable, on a EU plug into a UK type plug, save rewiring, if we'll put 3 core mains. To try a JVC without the SEA appealed. Balance Remote is an extra, if not there the Plug must be used to work right. Bulbs. The 880 for the meters uses standard screw in bulbs, unlike the 990 which has more obscure ones that are very hard to change. Plug In Boards. The Phono one the same as the 4VN-990 if others differ. 4 rear ones the power amp drivers, front ones Relay, Power Supply, SFCS 4ch effects & Phono. Large right board is the Pre-Tone. First Play. It plays if not very well, needs a rebuild, sound distorted & uneven. All 4 meter bulbs light. This would be sold as "working" on ebay, if it should be described as 'not useable as too rough' if basically works. Can't really describe the sound or compare it to the 990 yet. Service It Up. Try a Service on it first, to hear the Amp as near original matters to understand the Upgrade better. The 4VN-990 above was too hissy to really try it, so upgraded it before trying it much further, so a more subtle approach, if the amp allows it. After checking the 8 plug in boards before, the amp sounded awful. But Serviced to a degree gets it playing music properly, after a little more to get the Relay going. The open grille lets a lot in to age it. Sound As Original. Didn't expect to get a chance for how it was before, but that's Vintage Hifi for you. Upfront sort of sound, Bit of Hiss on the L channel & a bit of Hum if on Headphones turned up to '3' the music covers that. JVC on Tone Controls does well, we're more used to Tone than SEA. Punchy sound, detailed & wide Stereo if not a Sweeter sound as the design reveals. Fresher sound than the 990, this is a very decent sounding amp like the 1976 Marantz 2235B that was the last amp we reviewed part done. The background noise is quite strong now if it's a pleasant listen otherwise. Compare Raw 880 to Rebuilt 990. To hear any differences. Actually not so different beyond what upgrading brings, as in Finesse. Max Bass on the 990 can nearly be got on the SEA, max on 40Hz-15kHz & 1 step on the 2 next ones if 1kHz untouched. SEA button on cancel brings the 990 nearer the 880 sound, a subtle change. Back to the 880, a bit rough again to get it playing. The 880 is a richer sound where the 990 is a little thinner sounding. The SEA to us isn't quite as good as a NFB Tone Stage, the 880 has a very decent one. Goes a bit vague again as not rebuilt yet, if the 880 is a very decent amp & if to pick 880 or 990, with 55w or 88w bridged, the 880 has the edge. 55w bridged with Upgrades will be about 90w based on the Trio KR-6340 we had. Deeper Servicing. This one needs a lot to get it to Play as Original on all 4ch. To try it on Speakers if it reads safe. The 1976 JVC JR-S-600 as reviewed below had a great sound on Speakers & this 880 one is nearer to that than the 990, to find out why beyond the SEA as the JR-S 600 had SEA as does the 990. That Preamp-Tone Board. Pity they couldn't have done this board as two plug-ins. To add to the fact board must stay in as wired tight, it's Double Sided so expect fun replacing the Hissy Transistors. Makes you wonder if things are done this awkwardly on purpose. Doing this firstly to hear what the background noise will be after some work. Seems other hissy ones replaced in the 1988 repair, if one not replaced & they didn't do the Preamp, maybe they were still good, we only hear aged nearly 50. Final Verdict. Actually Sorted the Bad Noise, wiring done wrongly placed correctly. But then to try to Recap that awful double sided Preamp-Tone board, it's just not possible to either unsolder or resolder on the poor track & in such a tight space. As with any amp, if it can't be made good & reliable then it's no good to us. It did sound decent. Don't buy this amp. COOL RATING: 7 Looks purposeful with 4 meters & controls with added backing plates. (2021-2022)


1973 JVC VR-5525L receiver ↑
AS-ORIGINAL (Once Serviced): --. UPGRADED: --. 22w-25w.
FC, not Diff. 1973 was the Last Good Year for Many Brands & this for JVC is the First 'Non-Ugly' one, with looks like several others of the 1972 ranges. Only just rebuilt a JVC VR-5521 for a customer & reminded that JVC were always good sounding amp so to always pick them up, even if seemingly non-working. The VR-5525L suggests it's the next model with much nicer looks to the rather industrial 5521 if that sounded great on speakers once upgraded. Smart Wood lid is actually vinyl wrap but quality. Late 1973 it is, as "7311" date on the Tuner front end, so the 5521 must be 1971-72 with this 1973-74. No Manuals for this one either, if as with the 5521 it's likely buyable, if we don't probably need it, to know the correct power would help. 35v Main Capacitors suggests it's around 22w-25w as the 5535 is 30w. 5535L is likely very similar. But it's The Looks, much more attractive with aluminium lower half with quality controls & the upper half slightly slanted back. The 1977 JVC JR-S 600 was a decent receiver too, higher power, quirky looks. The 1978 Silver 'JAS' range we remember our Uncle having in the ELO "Out Of The Blue" days if they aren't so cool as IC power amps & a very different product to the Classic JVC that are all worth a try. Radiomuseum has the VR-5525LX with 190w (VA) the 5525L is 182w (VA) so whatever they changed, Tuner possibly. The Risk of ICs is the unknown & this does have 2, if they are very basic FA 6012 ones, similar to the 1971 Hitachi IA-1000 amplifier has, the shape of the transistor shows inside. The VR-5535 manual shows the IC equivalent, 2 transistors & a few resistors, the design looks fine if why the need to save space is just how Hifi was. There are two 4.7K values inside, not 47K. IC no problem. Blind Buy cheap & not working if liked the Looks. The Grey Double Insulated cable looks fitted by the shop, red electrical tape a bit amateurish but shows maybe a later year sale as the thin single insulated cables became unlawful to sell Hifi with. Seller showed with the Tuner lights on if they say no sound. Always a gamble, could be damaged or just need a deep service, it's Our Game to Gamble. Rear Panel is unusual, the central metal plate covers 3.3A Speaker Fuses & the Output Transistors. The Original ones are Complimentary NPN-PNP pair 2SC1445 & 2SA765 on the left if the right has replacements as 2N6372 & 2N6318 suggesting these TO66 type output transistors got relaced in about 1977 from seeing similar. The 5525 from 1973 is certainly a more sophisticated build than the 1971 5521. Speaker outputs here are unusual, an unusually large 4mm hole, but it's not for 4mm plugs, only bare cable, pull it out, insert cable & push in. If you put a 4mm plug in it fits but doesn't grip on metal so won't work well. Looks good to us, no damage so Service it & plug it in, a 3A fuse in the black bakelite plug is good. On putting an Input, to see Two Aux Inputs is good, not many amps do this in the 1970s. But is all this too good? Headphones on, huge loud Crackle only on the L channel. Seller knows it works but the Bad Noise scares them, re-reading their listing they do tell it is very noisy but we just bought it knowing it can be repaired. Been in Storage 25 years means 1994 if by the looks it hasn't had much use if was used to get the Outputs repair. No bother to us, it'll live again, the noise is very bad, just like the Pioneer SX-800A valve amp. What If You Bought This Amp? Once arrived to just take it as it comes as any Gamble & check it out ourselves. The Bad Noise could be more than just the obvious, but for the 46 years old age, to just Recap & Upgrade the Lot beyond the Tuner. It's a Quality Amp & to be done properly, the Rebuild Price will put many off as it's not a cheap job. To buy ailing amps cheap, us do a good rebuild & sell for a certain price is the idea, in reality the Job involves more than that amount if you asked us to Rebuild it. This is The Reality of Vintage Hifi, once it needs work to even be Useable, the Costs add up. Based on the below, an amp like this could need a lot more done than expected & the Sell Price to a certain level will be less than the work put in if priced as a Customer's Job. In cases like this, to really Upgrade more to sell a Very Special Upgrade can be a better deal. Still Gambling though. Rebuild You. Checking the Voltages, the Main Caps have ±28v which is just about the same as the 5521 so it'll be around 22w. An Old-Time Tech would waste hours finding the fault & just repairing the odd part, we just Recap & Upgrade the Lot, far more Efficient, Refreshes the Amp & will Sell as a Good Reliable Amp. A Lazy Repair may fail again soon & another Costly Repair just wastes your money. Maybe Interesting. The 5525LX on the Radio Museum site has a different Amp board inside as layout obviously different. 1960s big Diodes looked strange in a 1973 amp, if from other pics & soldering these seem original. A 5525LX on another site via Google images shows the later Power Amp board. This has 2 spaces for large capacitors that are unused, maybe a later design to use on another model. Adds 2 Fuses on the board instead of the ones under the rear panel, else looks the same. The limiting capacitors on the Output Transistors suggests the amp was too lively or too high KHz output. It's good when these amps throw up oddities, rather than just another general type one. VR-5525L is an interesting one, if the LX seems to have sold more, so L version maybe just failed Safety Regulations to be altered with the Fuses. But No Manual. This VR-5525L has no manual on any sites, even pay ones. But the Power Amp is the same board as the VR-5535X if some values will differ as higher power, one capacitor differs. No Relay on this Amp so no Protector board. Preamp-Tone-Mic board is the same if likely value changes. Phono has a 56K & 47µf extra joined midair, part of the Phono input. The Switched AC Outlet has a 4.7M resistor to ground, hardly a safe thing if seen on other amps. Now having worked it out, how good is it now? The looks for JVC is a one year design if sold 1974-76. It will rebuild well & is expected to sound good as JVC do, if to wish it was more than 22w as it interests. 2020 Revisit, the same amp as nothing done yet. 22w with a 50w size transformer. Just looked at the 20w Sansui 350a to find that extremely good if tided capacitors awoken with some use. Big Unit for just 20w & the revised looks. Seller had tried 'amateur' things, if never considering the rest, needs some tidying. Unusual with 'stopper' film capacitors on the TO3 outputs. Power 5515 is 19.5w, 5535 is 30w, so 5525 must be about 25w. Basic ICs on the SEA amp stage. Build quality moves on by 1972-73 if the JVC betters the Rotel RX-400A. One to get going & sell on, a JVC well worth trying. We got the 1973 JVC 4VR-990 amplifier too, that's a very special one. Too Much Messing? Thought this Amp was worth Rebuilding, if a closer look shows Amateur Fiddling to an Extreme. A few days thinking decides it's a Good Looking Amp so why not give it a try. Sometimes you have to quit, but JVC are worth trying more with. Whether the Work will be covered by the Sell Price is Unlikely, but why break up a nice grade amp with rough insides? We'll try some more. Verdict on This One. Some Idiot has actually Cut Transformer Wires & badly joined, wouldn't trust any of it. Multivoltage Block badly Soldered loose wire. Both are Ridiculous as in What were they thinking. Are there Errors? Yet the old Power Amp Capacitors Untouched. To even try to tidy this leaves an Amp Too Messed With. Power Amp Messed with, all manner of Stupid on this one. Output Transistors a Mess, TO66 outputs hard wired, no proper fixing, just isolators on Bolts. Messy there as Designed with Fuses crammed in & Stopper Capacitors differ L to R. It could never be sellable. Only a Crook would try to sell this in any form, especially as they know they ruined it by messing so amateurishly. All Electrical ruined, even unsoldered the Main Caps. A Menace to Hifi. Another One to Break Up, takes an hour to strip it down. Lots of bits that may be useful, fittings & wire looms. 2020 isn't a good year for Failed Amps, but it shows we'd not sell such items. Power Amp Stage is for amateur fidding too Poor, not repairable if Output Transistor damage, wires too short & to solder to TO66 pins is hopeless. 0.5 ohm resistor slabs with a bit of tape covered metal screwed on the back panel to keep input wires off, laughable. Preamp & Tuner looks good, Power Amp a bit budget. Probably would be a decnt one if in better grade, if the messing here too bad to sell. BUY-RAW RATING: Only buy if Nice Grade & Working, if Faulty, avoid or Bin it. COOL RATING: 6 Looks updated with this one year design. (2019-2020)


1973 Marantz 4230 Receiver ↑
AS-ORIGINAL (Once Serviced): Very Good (estimate). UPGRADED: Excellent. 2x 30w, 4x 12w. 4ch Bridgeable. CC. Seems to be the First Bridgeable Receiver if the similar looking 4415 & 4430 are 4ch only. Also it's still capacitor coupled as the 1972 Marantz 4060 4ch amplifier is, the earlier version on the 4070 below. Thought this was the one we had around 1996-98 if the insides were different & the usual 4 spring metal topped slanted speaker connectors, not the smaller square push button ones. This one is a Joy to see, Top Grade in the Box & with Paperwork, Marantz are usually well used. This being kept in the warm is very tired electrically, 47 years old now. It was bought early 1975 when 4ch was failing, the Magazines only say this by 1976 on reading HFN/RR. You get a Bargain 30w amp when used as 2ch stereo. This the early type with the small round fascia screws, the Hex Bolts seem to be models 1974 onwards. Paperwork included is Instruction book with an added note about Not Grounding the Amp when Bridged, Pre Out-Main In connectors being a new idea as early 4230 don't have this, rare version? Three versions then, small fascia screws with or without Pre Outs & a Hex Bolt one seen too. Schematic on glossy paper in Blue ink, dated '8-5-1974' as in Aug 5 shows the Pre-main sockets added in, if the pdf version doesn't show them in the top right. Old Repairs. The owner said this had been in 'For Repair' twice & indeed a twist joined 1.2Mohm resistor on the Ch3+4 bias is the least likely resistor to fail & a capacitor on the same Channels replaced seems to be the 'do something to show' idea of TV Repair Guys of old when it only needed a minor bit of servicing, but they wouldn't say that despite the issue solved. The Outside. Vinyl effect Wood patterned top so nice in high grade, the wood case not really needed. The Fascia on the 4ch Receivers perhaps the Best Lookers of the Marantz ranges. Smaller top row controls with Dolby which you can use for Playback of Records etc as we did with our one long ago, if not that much use if in 1973 the early heavy built Cassette Decks had no Dolby yet. Sliders for Balance & another 6 identical sized push buttons for high filter. Loudness, FM Muting, 2 Speaker sets. But how do you Power it up? the last of the 6 Buttons is the Power switch. Lower row is Tape 1&2 monitor, dobly, Input selector, Mode, Dimension, Bass, treble, Volume & 2 Headphones. Rear Panel is Different to the early version, adding Pre Out-Main In sockets & loses the external fuse. The 7mm square Push Button Speaker connectors here in high grade, the 4070 one were crumbled & showed as easy to damage. Power Mode for 30w x2 or 12w x 4 plus typical connectors like the 4070 if not the In-Out connector plugs as the Inside senses. Base shows 4 Original feet & an opening for the 4ch optional decoder. The Inside. Has the Black Cages over the Dolby & Tuner. Power Amps to each side, a Power Supply Board to the Left, Transformer looks nearly the size of the 75w JVC 5040 one. A Single Power amp Capacitor as pre Semi Complementary design, with 3300µf 35v output capacitors on the Amp Boards like the '4060' has. Lightbulb casing in Plastic needs taking apart, these can go very crumbly for the Bulb Heat, LEDs preferred these days. Underneath shows the early 'Screw Block' Multivoltage that needs a UK Manual to tell how to do this, see the 4070 below. Boards for Tone, 4ch & Dimension. all nicely made if the wiring for the Power amps as tpical with Marantz is not user friendly. See the Marantz 1122DC review for how much taking apart is needed with Marantz. Fuses are underneath, three of them. Power Amps have TO220 transistors, not TO3 if are soldered in. No hissy 458's as 1973 if the capacitors are all to be done beyond Tuner. Small Phono board has ICs as does the 'Vari Matrix' Dimension board, TA7129P used by other amps & still buyable from NOS as unlikely to fail. The Circuits. Trying to trace the long board lines is quite a job, if the Boards say what they are. Aux to Tone Stage direct, others quite like the Marantz 4070. Power amps Input Stages, Driver, Protection, P-P Driver & Outputs gives the Fresher Faster sound, no Differentials on a Marantz will be a New One to us for the Sound. Outputs are all 2SC789 as the '4070' was, TOP66 style 30w 4A. Main cap is 4700µf 55v if works on 48v as the Capacitor Coupled design, if a Differential design it'd be ±24v. Sound as Original. It was Tired with One Channel lower & usual aged noises. Not to try it more than once as it needs work rather than risk it. Couldn't really tell much. Very well Made for a Marantz, a pleasing amp for sure. Recap & Upgrade. 14 Boards including Double Power amp is a lot to do, if we've done a few 4ch amps now to know the amount to do. Dolby Board is P600 one. It works by varying the Noise Floor level to lessen 'noise' to Dolby Standards of 1973 by varying degrees. Likely it's 'Dolby A' before the more Universal Dolby 'B'. For Tape of Dolby FM with UK never got. Played with the one on another 4ch Marantz receiver years ago. It's like a 'Continuous Noise' Filter as on more Advanced Audio Programs like 'DC Art' if it's variable by level only across all frequencies, not adjustable. Can be useful for 78s playing 'Live' if these days of not so much use, but like the 1971 Trio-Kenwood KR-6170 with it's Beat Box & Reverb, nice to have in a retro way. 8 Transistors & a FET per channel to 'Record' & 'Playback'. Seeing what it is & a Feature to keep working, best Recap that too. Working On It. Marantz always hard to work on for tight wiring, needs thought & patience. One Power Amp done shows it's a tricky one, if a worthwhile amp. The Big Caps are Speaker Output ones, it's a Single Voltage amp like 1960s ones. Recapped In One Go & Now To Try. Takes a lot of board checking to be confident to do that, especially when it's not playing right & not wanting to risk it. On it goes & 'Uptown Top Ranking' is it's first song. Controls & Headphone socket need the servicing as intermittent, if played in Stereo most the track on 2ch mode. The Boards are very cramped especially the Dolby board & wires short as typical Marantz. But soon forgotten once it plays & sounds nice, if only a quick test so far. To Service more & adjust then rate it. Now Serviced. Lots of switches & buttons plus to set them right to use, if now plays all channels, 4ch by both Headphone & Bridged to 2ch. What's It Sound Like? On Headphones, Clean precise sound if a bit Bass shy to try this. But it is a 12w 4ch Receiver in reality, if Bridges to 30w or more. Not going to be Too Bassy as 12w limits. Still punchy for the rating if not the Huge Dynamics of some, like 75w amps if you'd not expect it here. Plays Rock with a good Sound if not the Bass weight, midrange is decent. Needs about +2 on Bass to sound decent on Headphones. Wide Stereo & a Pleasing Sound for the Power Rating. A Good Taste of the earlier 70s Marantz, if at a 12w design leaves us wanting more Power which is always the thing when the amp basically sounds good. Testing. Puts out 16.5v Clean Sine on 4ch which is better than 12w as Rated, easily 16w based on others. 2ch Bridged is about 32v so again underrated, puts it int a 60w rating if that depends on Design taking advantage of that, the 4230 is a bit tamed for it's 12w. Looks like it could upgrade more, if not to experiment on customer's amps. Speakers For You. On our Tannoys, try as 2ch Bridged Mode. Sounds great, clean detailed treble, solid midrange & a nice Bass. No Tamed sound here, if using Bridged is the thing. In 4ch Mode gain is less & it sounds Tamed like it did on Headphones. 2ch Bridged Mode to 4ch the biggest difference in any 4ch-Bridged one yet. Upgrades bring a proper Deep Bass that the Owner will not have heard before. Was thinking it's not quite an Excellent, but on Speakers it sure is & matches 1968 Tannoys well. Further listening on Speakers shows a silent background & a very smooth if detailed sound with the Low Damping Factor Bass from Bridging. On Speakers one of the Better Marantz easily. Why So Different? Headphones to the F/R Sockets direct, in 4ch mode only not Bridged, only Speakers are bridged. As 2ch far better than 4ch. But Later... on Testing all before returning to the Customer, the Headphones sound was much better than previously. What Did We Do? Used it on Speakers for over 2 Hours after Running In for More Hours so clearly woke it up more beyond recapping & upgrades. Lack of Use maybe for Decades? BUY-RAW RATING: Marantz are nearly always too aged to use Raw if many will put up with the Below Standard quality it brings as kept in a Home setting for longer. 1973 is 47 years old. Well Worth a Rebuild if it's not Cheap as so much to do. Keep These Classics Alive. COOL RATING: 8 smart looker, if familar to us from c1996. Big Wood Case available if an Original one best, looks nicer without a case. (2020)


1973 Marantz 4070 Quadraphonic Amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good (estimate). UPGRADED: Excellent. 2x 35w, 4x 15w. 4ch Bridgeable. DIFF, SC.
To try a Quadraphonic 4 Channel amplifier was an idea that we've yet to discover as of July 2018. We happened to buy a really good one & it compares to the Trio-Kenwood KR-6340 as below that we got Nov 2018. No rating as 'Original' as ours needed lots done first. There is also a Marantz 4060 4ch amp from about 1971 if that's not a Bridgable one. As on the July 2018 blog, we've always dismissed these for the Fact 4ch is Obsolete, not compatible with 5.1 of today & the fact 4 x 15w can be bridged to 2 x 35w often leaves a dull blurry sound. See the July 2018 blog for more on 4ch & Bridging. This we took a gamble on as it's just the amplifier, without the Tuner & instead of getting one of the Receivers that have the bad fascia lamp plastic. The big open top grille lets all the muck in & dust bunnies aplenty, but we've had worse that cleans up nice, so worth a try just to get a fresh opinion. The 4070 is like most 4ch amps, it was likely sold off cheap to clear once 4ch failed so you rarely get the Decoder board. We had one of the Marantz 4ch Receivers in the mid 1990s & perhaps it was most likely the Marantz 4230 or the Marantz 4240 as the fascia & layout is identical looking at our photo of ours. Didn't think too much of the sound & the amp was only 22 years old then, today the 4070 is 45 years old & age shows. Here beyond the muck inside, the speaker connectors are a sort of 'cage' type press button if the plastic decays so the speaker connectors are useless, if the modern small spring ones can be fitted with a little work, so worth restoring one. Amp is smaller than expected knowing the Marantz 1152DC, 360mm wide x 132mm high x 277 deep. As sold off cheap in Comet it gets sold lower in status than the $300 amp it was new in 1975 so these can have a hard life, if the fascia is good & control parts intact. Inside was intriguing in the seller's pic, beyond the fluff it's densely packed as 4 channels amp in one case, no ICs in the design & Bridgeable. The 4ch Receivers are Bridgable too so they are still useable, if wondering how they sound is why we got this one. Some 4ch Amps we've looked at before to see ICs used so dismissed those, but here all is Transistors, Phono is 2ch having 2 transistors per channel, with the Decoder bringing 4ch from the Record encoding, assuming formats match, ours has no Decoder as lacked the 4230 years before. The Bridging-Power-Amplifier mode involves 4 wafer switches & lots of lines on the Circuit Diagram to really take some work to find out what it actually does. Tone is 4 transistors per channel including Buffer Stages. Optional wired remote control, the circuit shows it likely only alters the Front & Rear Volume controls. Voltage setting. The UK model has an awkward board terminal block with 6 wires. The Marantz 2230 manual shows the details on how to adjust this if the wire colours differ, the placing is the same. Ours was wrongly set to 200v explaining all the problems if set to 240v it'll work better. It probably never worked right in the UK as we found after all the work as the Preamp Voltage using 200v setting is too low for the Preamp regulator to work. Difficult to Work On. From taking this apart to check it, this is bordering on the 'unrepairable' to some as even to get to the Fuses board involves taking apart. The side power amps are tight on wires involving a lot of taking apart to even fix anything. The upright Preamp & Power supply is similarly involved. We'll have a go as we want to hear what it can be, but as a Repair or Upgrade, it's a difficult one, which we've found with Marantz 1971-77 gear before, it's not Tech Friendly. The reality is with quite a bit of taking apart it can be done. Considering it's Double the Circutry of a Stereo amp in such a small package, many would give up as the Repair label showing it was abandoned "Too Far Gone" tells. The General Electronics Repair shop is still there, if likely refused long ago. We've had far worse than this & got it to our standards, takes a specialist who wants to take a challenge & a customer who sees the work involved. The plug was a disgrace as shown on the blog about it's previous status. First try shows life but far from the seller's description as typical, needs a recap as is usual on Marantz & Pioneer of the era. To fully recap is the only option, a bigger job to do than the resell price, but one worth finding out. Design of the 4070 is a very densely packed amp, to work on will be difficult. Working out what to do, the amp is a good design in circuits so will have sounded like the 1971 Marantz 2245 we had that upgraded well if typical Marantz weaknesses in the spec used plus the small capacitors they used don't last as well as other amps. Maybe they made it this size just to fit in with the Stereo Amps & Tuners size if it is very cramped up. Main caps are 10000µf 35v if in effect there are 4 preamps & 4 power amps in here. As blogged the Bridged Design we alreay know via the Sansui AU-G90X & it needs critical adjusting to sound crisp & bassy, else the sound does lose the Hifi quality. 'Bridged' is called BTL Balanced Transformerless Connection & the Rear 2/4ch switch operates the Phasing Alteration & alters the Speaker Outputs. The Leak 2000 is a very different design of 'Bridging', see that review. In theory if upgraded & adjusted right, the Bridged Output should be as good as a 2ch amplifier & with halving the Damping Factor, it may actually be pretty good. The 4070 Power amp is a better design than the awkward 'sound shaped' & adjustable balance of the 1971 Marantz 2245 design, with Differential, Driver, P-P Drivers to outputs with 2 extra for Protection. At the time we had the 2245 from 1971 & the 2265B from 1977 finding the later one the better sounding, looking at the circuits, the 4070 appears to have a better circuit than both those on the Power amp. To look at the Marantz 1030 which is a 15w amp, the design is quite similar if no Differential so should sound similar. Big Job To Redo. The preamp suffered for bad caps with transistors damaged, so just redo the whole preamp, decoder stage, power supply, buffer stage & phono with capacitors & transistors, to unsolder the pin wires is the only way. This sort of job would be very hard to price not knowing the problems & the work involved may outprice the job, but it is a Marantz which do make good money if few dare recap them. Trying it from the Soundcard to play the Power amp only, in Bridged or 4ch it sounds no different as recapped & is a good sounding one with wide Stereo if limited Deeper Bass. The power amp is just recapped not upgraded more or adjusted yet, it sounds decent if gets confused on busy Rock as most amps do. More upgrading is possible in this amp as we've looked already. Power Switch on ours was sometimes bad & a switch that switches mains on when 'on' plus puts a circuit when switched 'off' means that for the lack of switches buyable & one aspect on either side of the switch never used, just swap the used to unused, after cleaning the insides. The only new ones we found were only 4 pin, not 6 pin with different panel screw mounting, another disappearing part. Got It Working. Probably one of the hardest amps to get right for the 200v setting difficulty plus how cramped it is with 4ch amp in 2ch amp size case, but now it plays. The sound is lively & fresh sounding, as recapped on all with new preamp transistors. Not biased it yet & switching 4ch to 2ch bridged does reveal it does blur the sound, but the sound isn't fully crisp on treble on 4ch either so it doubles the blur. The 15w stage is surprisingly good on headphones, if it upgraded quite a bit already, a rich bass is a little Retro Bass if once Biased right it's not a problem, at least on Headphones. Bias-DC Offset Adjustments. The manual says how to do these if to remember it's x4 as 4 channels. Ours was set on the original Bias settings as dirt & paint marks show, if testing it was quite off correct values. The Power amp board recapped if original transistors. The Sound is much crisper now for Biasing right & the 2ch mode one adjusted right now sounds no different when as you can see just above it just double blurred it. Now Adjusted right, the 2ch or 4ch mode sound the same & the amp itself sounds a lot better than we expected if there's more we can do still. Sound Quality Now Biased is far more precise, Stereo is wide & clean. Interestingly the amp deals with Rock well sounding a little richer for the Retro Bass if weightier than you'd expect, if on 4x 15w it's a bit thinner, but on 2x 35w mode has enough weight. Actually we don't remember the 2245 or 2265B sounding as good as this does, both those got some recapping when here 2012-13, the better simpler circuitry in the 4070 power amp tells. Sound on Tannoy Golds. The ultimate challenge. We've dismissed Quadraphonic Amps like Monster amps as being Aged & Blurry which They Are as Original. So to hear this on Speakers with DC Offset rechecked & rebiased is an interesting one. To use it in Bridged Mode to get 35w. It sounds as good as we've heard from other upgraded amps & the Power amp can upgrade further. A very clean precise accurate sound. Nothing weak, grainy or blurry here, it's spot on. Bass not as strong as some if the Power amp is much as original. Didn't expect it to sound that good. Sine Wave Output on 4x 15w is 16v clean Sinewave, on 2x 35w mode it reads 34v clean Sinewave which is more like a 65w amp, see more on the Oct 2018 blog. HT is ±24.3v on 10000µf 35v capacitors. BUY-RAW RATING: If cared for & used the right voltage should be fine beyond usual aging, if the top grille lets in all the dust. UPGRADE RATING Double the channels means double the work & a difficult amp to work on, a rebuild will probably outprice the amp if the sound is worth it. COOL RATING: 7: Cute amp with lots of controls, would look better in the WC-10 wood case. (2018)


1973 NAD 90 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 45w.
SC, DIFF. The amp version of the 160, probably from 1973. The sound is very similar to the NAD 160. Early NAD were still midpriced but did have a fine sound, but the best NAD buy is the 160 receiver, the 90 amp version was a lesser beast in sound & construction was a bit junky with a card between two inner boards looks a bit amateurish. Strange the receiver version is so much better. The NAD 90 lacked the sound focus of the NAD 160 & actually looks like it was built very differently to the quality of the 160. A 2012 review & we did try one later that was trashed & found it not worth bothering with again, unlike the NAD 160(a) that we've had a few of. BUY-RAW RATING: Good. COOL RATING: 6 lacks the confidence of the receivers & looks a bit cheap beyond the fascia. (2012)


1973 Nikko STA-5050 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 24w.
FC, DIFF. Seems to be a 1973 model, the STA-7070 & 8080 are in the 1974-75 HFYBs if the Build quality is much more 1973 as it's still of a quality pre Comet Cost Cutting era. STA-5050 is belatedly in the 1976 book if no price shown. Got this one as it had 1972 looks, it's quite a big unit for the contents & weight 422mm wide, 364mm deep & 140mm high. The case is a tidy vinyl wrap & the looks are smart with Aluminium controls, a push button power switch & 3 lever switches. The Front has 'Tape 2' which is a Line In-Out so you can plug a MP3 player into the 6.3mm socket via a 3.5mm adaptor plug, Few Amps have this feature, modern life-friendly. The 7070 looks like an Akai, 8080 like a Pioneer, the 5050 a mix of Rotel & Hitachi. More pleasing build than the 1970 TRM-1200 that had IC as the Phono input, to be sure this was Transistors & it was plus a decent design. Rear Phono sockets for Phono, Aux, Tape loop inc DIN duplicate. Some odd connectors for 4ch use if it's a 2ch Stereo amp if 4ch FM Composite. Circuit Breakers as 1.6A fuses is a Nikko quirk still here from the earlier amps. Speakers connectors are the tiny square push button that Marantz uses plus Phono ones too for cheap speakers no doubt. A few issues we see as poor selling, 2 core mains wire cut short plus the AC outlets loose as the plastic screws break, so some tidying to do just for safety, what would you do with that? It's Unsafe. Inside is quite minimal, if the Gold Cadmium plating looks nice, odd to make the case big with lots of space, if maybe to match the others ion the range. Small but Cute Transformer, the Power Amps on one board with the Heatsink inside if TO3 outputs 2SD188 & 2SA627 so a Fully Complimentary design is still unusual to see for 1973, not even Marantz did FC if JVC & Pioneer etc did. 1975 wouldn't have certain features & the TX has a '573' code saying it is 1973. Play Me. Need to set the Rear slider to '2ch' else no Music. Subtle Blue Tuner light & Orange Tuner pointer light, bulbs needed though. Like this amp, somebody put a neat mains cable upgrade since we last saw it. Silent Background, plays with No Issues. Re-Reading our other Nikko reviews from 2012 & 2015. The TRM 1200 was a quirky one that was built a little odd needing alterations, the 22w TRM-500 below looking at the sales photo has some similarities if didn't recap it, looks good. Nikko certainly better by 1973 is the point. Sound Quality is very decent, clean fast punchy sound, no grainy sound if Bass is Balanced it lacks the Bass weight, if most amps do. Reminds of trying the 1970 Sansui 350A the first time as the sound is better than expected. Both Simple Classic designs with the Right Parts, no ICs, TO3 outputs & good looks. Stereo is Clean & wide, to look at the Circuits now as it's surprisingly good with a bit of Soundcard Bass EQ. Circuits pleased to try it. Phono x2 transistors. Aux into Tone-Pre after Volume. The Circuit drawing style like another amp if ?? The Tone is a Baxandall NFB one if a good one. The 4ch goes before Tone which means it'll be a lower level to some amps. Power Amp is Differential with Adjust pot that is unusual for the price range. Then Driver, Bias, P-P Drivers to the Outputs. No Protection nonsense & the Circuit breakers act fast as found before on similar. Power supply shows a space for a TO3 bridge rectifier like the NatPan SA6400X uses AS2HB10 long obsolete. Build quality is Decent, Power Amp a bit cramped, wires a bit untidy to the outputs, short soldered Ground strip to the case & Aux is a long Unshielded 40cm wire if that can be bettered. Rear Panel is plastic coated like Marantz lids. Better Speaker outputs & more substantial feet would make this nicer. More On Sound. Onto Rock which really tells a Good Amp. The Speed & Detail define a good amp. This has good weight & solidness to the Midrange, even with no EQ, no muddled grainy sound that Rock can bring, like the Pioneer SX-850 breed. Nikko have a reputation as a bit lacking, but this amp is totally different & surprisingly good. Sounds better as Raw than the 1973 JVC 4VN-990 did on first tries. Just a smart & crap free design, with a late 1960s quality. A Rare Find. STA 8080 gets a look at to see a higher model, Akai AA 8080 looks. Phono x3 transistors, Tone x3 if a little fussy, Power Amp the same. Would expect the 5050 to sound slightly fresher than the 6060, 7070, 8080 & 9090 as all are unusually good. Real Sleepers. Back to the STA-5050. Works on ±29v suggests 24w is modest once upgraded. Says 76dB noise floor which on Headphones sounds a lot better as no hiss at all like a 90dB one. Tone says ±2dB which isn't right, typo, easily a ±10dB one & plays clean on max treble. Played it for over 2 hours not even cleaning or much servicing beyond a quickie. The TRM-500 has the STA-6060 design with extra Transistors in Phono & Tone. Nikko slipped out a Gem here, if who would have known in 1973, amp around £120-£130 is decent Midprice level with 24w to use with the Shoe-Boxy £25 speakers of the day, not Tannoy 15" Lancasters as it should merit. Any more Surprise Amps out there? This one certainly is. To Upgrade. Not much to do in this amp, Sweet & Simple much like the Sansui 350A was. Spec is modest here, might not drive 15" Tannoys so good if It's In The Upgrade & one well worth doing, still looking for amps around 20w as these can be fresher sounding than 50w+. Try it again & put on Speakers to try if it tests good, just to hear it as original. A deeper look shows they may be giving a great design here in terms of Upgradeability, if as usual many spoilers & limiters. Try It On Speakers As Part Recapped. Test it again & give it a try. On Headphones it still sounds good the next day, to hear the limitations if still it sounds decent, a little softer on high Treble if Bass seems fuller for being used. DC offset on the Outputs is high at 185mV/-65mV adjust on Top Pots, way off if never touched so it's aged. Turn on is a slight Boop as typical of no Relay amps. Some quality in Upper Midrange shows which defines a good Amp. Bass is limited & a bit thick sounding for it. Shows it's worth Upgrading more as it's not showing it's Best on driving 15" Speakers, if the ones we've trusted to try as Original are much the Same. Our Upgrade brings the Best Out. Turning Off gives a Sound Bloop that's not good, if as the DC offset shows, it is a bit aged. Error on Service Info. The pdf of the Board Layout shows "2.9 Reg Amp PCB" is incorrect, it's ±HT, not +HT & Gnd as Single HT. D902 mid is -HT not Gnd. This seems to be an Error on that diagram only. Errors are not that rare but for the fact you may ruin the amp with the error, to tell. Being Upgraded & Recapped. In a Halfway stage to check the Circuit Breakers don't trip, to hear what it sounds like with some done. Just part of the Power Supply done gives more confidence on Headphones. A bit Surreal Sounding for it too, if still that Quality sound. Sansui 350A quality here, if totally unexpected, not so unlike in looks either. To get it to be that good on Speakers is our Upgrading, as a Blog tells on playing it on Speakers as Original is possible. Power Amp now recapped & tidied. No Circuit Breaker issues on Headphones. Sound is very decent & Upgrades bring Bass out nicely if within it's 24w rating. Might as well Recap the Tuner as not many. Never thought it'd be this Good, if the Speakers to try next. Adjusting. DC offset on speaker outputs with the top adjust pots on the Power Amp, can get better than Manual suggests to get ±10mV. Bias 10mV on the protruding black wires. DC offset still good after Biasing. On Speakers. Upgraded sounds a lot better. Not a perfect match to our Tannoys as other 1973 era amps have told, Treble doesn't change too much if does on Headphones. Healthy Bassy Sound for 24w though. The Amp is a good Midprice Amp if it has no Relay so a tiny Noise on turn-on & a slight 'fff' noise on turn-off. Not a Big Brand Amp at 3x the price when new, if sounds nice when playing with No Background Noise. Wide Stereo with a Lively Sound with Treble (sound, not tone use) up fully. Puts out 21v Clean Sine which is more like the 28w Pioneer SX-990. BUY-RAW RATING: Depends how Aged these are as 47 years old, ours played fine first try. COOL RATING: 7 classic looks taking the best from other brands of the 1971-72 era to make a rather good amp with neat looks. (2020)


1973 Nikko TRM-500 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 22w.
SC, DIFF. Sounds more like a 35w amp & looks more 1971 in design, semi complimentary, punchy sound could easily upgrade to improve the treble focus. Another Hidden Gem & a Bargain to buy. We liked it better than the similar small Rotel noted above. Nikko made lots of amps & receivers if they're not much around. For only 22w it played louder & coped well with bass within it's design spec. Looks like Trio & Teac inside & sound is lively and you get real teak veneer. A higher powered version would be interesting. Actually only 22w but clearly a punchy sounding amp. Not tried any other Nikko since this, not many around to try, but we'll keep looking. 2020 Update. The Nikko STA-5050 above so good, compare it to this one. Design more like the STA-6060. Certainly Underrated Amps for the 1973 era ones. BUY-RAW RATING: Good. COOL RATING: 7 smart looking with wood veneer case if quite typical looks otherwise. (2012-2020)


1973 Photax Concertone 800B amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 32w.
Cute & obscure amp together with the matching tuner, Very Good lively sound that is really just a little less focussed than others. In real Teak veneer too. A Very Good little find, nicely made & worthy of recapping to bring out the sound further. Looks quite like a Sansui in construction. It does have ICs but ones basic & early enough not to worry at this level & we still rate it a 'Very Good' for what it is, belatedly appears in the 1975-76 hifi books. MORE INFO: April 1974 HFN/RR introduces this brand. On looking inside the amps they look more late 1960s for build design if an IC on the preamp & later power transistors. One of those better Budget brands if wood veneer is unusual by 1973. The advert shows the whole Photax range & they are related to the Camera company. Amplifiers 420, 620 & 800B. Tuner 620X and receivers 22 and 333, see below for the 333. The 620 amp is rated 24 watts, also a 2000P turntable & 3 speaker models. But their timing in the mid of the 3 day week early UK 1974 problems kept this one obscure. Perhaps the better finish costing more put buyers off in the more budget range, if they did exhibit at the 1974 Hifi exhibition. BUY-RAW RATING: Good. COOL RATING: 6 wood veneer lids with basic looking fascia but with the tuner it looks cute. (2013)


1973 Pioneer SA-9100 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. 60w.
FC, DIFF. This amp is getting silly over-excited reviews (by sellers naturally...) saying that this is the "Best Pioneer Amp" & it sounds "Absolutely Fantastic". "Not So" is our verdict knowing other Pioneer of the era. But it certainly is the nicest sounding Pioneer Amp if only based on upgrading it & knowing others on this page. The original spec amp is disappointing: it lacks the kick you'd expect at this sort of power, the treble is soft, the bass is limited & sounds artificial, as well as the over complex pre-tone stage is a professional opinion. We know the 1974-75 Pioneer as you'll read below & it seems these silly reviews are by those who have never heard the 1965 Sony TA-1120 for example. Pioneer foolishly let their Hifi be sold in Discount Stores, unlike Yamaha & seeing 30% discounts in 1972-73 on amps like this sadly meant Pioneer had to heavily cost cut yet still make out their products were good. This means specs of design will be cost cut & to those who see past amateur opinions, these 1973-76 Pioneer are sadly Rough sounding with No Bass. But as below shows too, Pioneer are still Very Good amps, the circuits are good, but only after some severe upgrading, revealing what they should have sounded like & probably did nearly when designed, before the cost-cutting began. The circuitry is very like the SX-838 below & it was a tough one to upgrade properly as so much was dumbed down, but it did sound Very Good, if not World Class, once upgraded. On seeing it, a bit smaller than you'd expect knowing how huge the SX-838 is, 429mm wide x 309mm deep x 134mm high & 13.6kg. Small hole spring speaker sockets, better than those awkward plugs, still the same 1967 style voltage changer-fuse block & pre out-power in sockets with level controls for Phono 2, Aux 2 & Speaker B if oddly still early double mono Mic input sockets. Phono impedance selector too, so several things like the SA-9500 has. The Phono uniquely has L+R on separate boards, if perhaps more to fit in the amp than a design idea. The fascia is soberly laid out unlike the busy receivers, but noticeably odd is the two Bass & treble controls that seems to allow Tone shading, the 20kHz one is a bit pointless as it has two Filters & the strange Volume level set option plus another for Muting, a bit neurotic here. Not too different from the Sony TA-1130 in terms of features really beyond that. Has a smart walnut real veneer lid, unlike the tatty effort on the SX-838. Inside is neat, a cage over the preamp & power supply if it is a bit cramped up. The original spec in this amp as we look to upgrade it is typically weak, but sadly this is the Pioneer way after the discount stores ruined the profits. It looks well made but every penny spent in what doesn't show has been saved, very bad business sense. But these Pioneer do upgrade very well. The power supply board is awful as it gets too hot under the cage & fries the board risking failure. The stepped tone controls are hard wired unlike the PCB mounting of the SA-9500. Underneath is the protection circuit & filter amp with the other half of the phono boards at the front corner, the rest is passive switching. The 15000µf 50v power caps are very high value for 1974. The small board in the middle top is the first stage of the power supply, with the left front board the regulators, quite like the SA-9500 in part but hiding hot regulators in a cage with just a few vent holes is the weakness here, The rest we are impressed with. It looks quite like the 1969 Trio-Kenwood KA-6000 too, rather than the more modern Yamaha range. So to play it, unserviced & raw, to see what excited hypists are hearing: beyond noisy controls, the sound is more like the SX-828 when we got it than the less impressive SX-838. It has quite a lively sound that will impress, but we can listen deeper with known tracks & hear the foundations aren't so solid. Bass is there if in that retro way with a slightly boomy mid bass that impresses the unaware, if the deep bass, as with Pioneer & many other amps, shies away. Treble is smoothed off, a bit rough edged here but known tracks lack the open treble top end. compared to sound we got from the 1972 HK930, this is a cardboard version, but shows upgradeability is here. The more tracks we play, the more artificial it sounds, the one-note bass isn't right & it's clearly tailored as the spec shows, but it will impress the inexperienced hifi listener as it does have a good sound. Onto some Rock and it brings contorted facial expressions as the low spec hits with Punk-Rock Guitar sounding quite soft & rough even up loud, no real bite or kick, if decent to many still, it's weak to us. Stereo width appears decent if hard to be sure as the treble detail is soft. As all-original, we'll rate it 'Very Good' though it's not serviced but has been used recently that will have woken it up. In comparison to a raw 1977 Yamaha CA-1010 with a much more confident sound, the SA-9100 is polite & inoffensive but certainly adequate, if lacking the precision that makes Excellent amps. Loud midrange detail in a track can be heard breaking up as the spec doesn't have the confidence to allow full resolution, this is the Pioneer sound by this era. The false one-note bass does becomes tiring after 20 minutes on headphones. Looking at the amp innards as we work on it, very nicely made if pretty cramped up, you can see why the SA-9500 was so much larger. One issue is the Low Filter switch needs to be set upwards else it still filters bass through a small capacitor, you'd have thought midway as the others are for Flat would be more sensible, if actually the power amp already has a subsonic filter in the circuit, again doing things doubly is the deal here, the spoilers-designer must have had personal issues to be so wary & spoiling the sound, be sure it was designed to perfection & dumbed down as much to stop the public moaning when using cheap gear with it. Now upgraded, not easy with the tightly packed amp, but you can see it's worthy of an Excellent as it certainly is: clean, crisp, correct bass without the thick limited original sound shows this is a very fine amp once upgraded. On putting it all back together, the feet are too small so it sits too low, needs 1cm more height to aid ventilation. BUY-RAW RATING: Surprisingly Risky for the cramped power supply board overheating-low spec, the one under the cage on the left. No easy buy here as with the Yamaha CR-2020 as it'll fail for sure if not sorted, but once upgraded a great amp. COOL RATING: 7 smart sober looking amp if a little excessive on the controls makes it a bit busy. Real wood veneer here. (2015)


1973 Sanyo DCX-8000K receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Very Good-Excellent. 40w.
FC, DIFF. First thing, rethinking Sanyo: a brand later tainted by much Dixons quality crapulence in the 1980s onwards, ignore all that & look at this 40w fully complimentary amp from 1973 like it deserves. Looks very like a 1973 Sansui Eight or a 1973 Pioneer & inside like Teac or Hitachi, Sanyo designed & made Transistors & ICs so are well worth a try for early Hifi. Smart looking silver front with the usual quality of a 1971-73 receiver. The power amp section is caged. This amp is all Transistors if typical Tuner ICs. Transistor count is decent: Phono x2, Tone-Pre x4 with 2 of those as Buffers, Power Amp x10 if the last 6 are the push-pull stage so it'll sound good & upgrade well. Headphone resistor a little high perhaps. 4700µf 50v main caps is typical for the age if a little mean. In a 1976 shop ad for £132, probably end-of-line price on a £180 item, but still decent midprice quality amp with a quality sound, more advanced design as very focussed, accurate & clean on the midrange. As original Bass is a bit retro-limited & Treble with likely ceramics is a bit fizzy but but easily deserving a 'Very Good' for all-original as the quality is there with an accurate sound balance. Not much with Sanyo apart from the 1968 30w receiver DC-60, others just low power. Betters the NAD 160 which is a similar sort of receiver in quality. A good find. Probably exported more as one seen on ebay.de. A bit low spec overall originally, probably to keep the sell price low, but it deserves better as it's a good amp. So after giving it better spec on Pre, Power Amp & Supply it transforms into a different amp with deep bass sounding as good as many of the above amps. As buyers will be cautious of Sanyo, we'll not go further upgrading it to keep the price accessible, but Judge Not the brand name on their earlier gear. But in tests with other amps (as recapped & upgraded), it didn't ashame itself at all & is worthy of upgrading further as the sound is clean & honest. You'd never think it was this good. Sanyo's Golden Moment. Sounding fresher than the Pioneer SX-838 with ease, the sound is like the 1971 Yamaha without their weak preamp. The range the 8000 appears in with the 4000 & 6000 appear in a 1975 HFYB advert, but never the book pages, boasting of Direct Coupling & Pure Complimentary Circuit. BUY-RAW RATING: Good. COOL RATING: 6 typical looks of the era copying Pioneer if undistiguished for any higher rating. (2014)


1973 Sony TA-1150 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 35w.
FC, DIFF, 2x IC, DOUBLED OUTPUTS. **Updated New 2018** This was The First Sony we ever got, a skip Find one at a Car Boot sale about 1990 for £5. In those days no circuit info & we never got it working as it just blew fuses. But we got another around 2007 before getting the TA-1130 & got a STR-6120 very cheap just to see what it was. the "Last Classic Sony" with the similar look to the 1965 TA-1120, this has ICs in the Phono & Preamp. we remember it didn't sound so good & found the resistor that powers he Preamp IC was unbalanced on ±HT supply. Back in 2007 this 1973 amp was only 34 years old & still worked right if now in 2018 it's 45 years old & we're finding amps pre 1978 are now often needing the main capacitors redone. The looks of this are still pleasing with the lever switches if getting away from the rather confusing mix of Lever & Rotary for inputs with a line of Push Buttons for Inputs plus a lever switch for Mode & Monitor which is really all the difference to the TA-1140. Rear panel adds a 4ch Loop & the Volume Control works on 4 channels not 2 if there is no 4ch circuitry otherwise. TVK says this was first out May 1972, if this is a 1973 amp to us, Sony wouldn't update the TA-1140 that fast, the service Manual is dated 1973. Later versions as it was sold past 1975 have Spring Connectors for speakers, not the TA-1140 type screw block. Build Inside. Quite Different to the TA-1140 as there is an unusually large Transistor Heatsink saection with the small TO-220 size transistors, but there are 8 of them. this isn't for 4ch it's Doubled Parallel Outputs. 2SC1060 & 2SA 670 are ones used as Voltage Regulators if they are good for Power amps as 3A 25w rated to give better 'Music Power' on a 35w amp, but why not just use typical TO3 outputs? Last of The Classic Sony if with ICs. The ICs are CX-0461 & CX-0462, a strange heatsink tabbed item long obsolete, if they appear to survive, but if damaged, the amp is unrepairable unless you get a spares amp. The Preamp-Tone-Phono-Filters are on the front top boards, the ICs quite hidden amongst wires & parts, but it's still Quality Build unlike the 1975 TA-3650 type. the Power Amp is on the front edge of the Heatsink area, tucked under the preamp. Much less circuitry on the board compared to the TA-1140, a Power supply as with the TA-1140 if a simplied one if still with a Regulator. TA-1140 has 12 transistors including it's Power supply, the TA-1150 has 12 if the Doubled Outputs, just fitted in to look less if quite like the TA-1130 more than the TA-1140. Differential as typical if no ICs. Power Supply is a bit more Modest, but it's still a Good amp overall, the ICs we'll test later to see if they affect anything. Circuit. Aux goes through many switches to Volume & Balance, to a Buffer, then NFB Tone around the IC which puts L+R onto one IC There are 3 further transistors for Muting when the Power switch is used if the Manual lines are weak to follow. The IC works on ±14.5v so likely it's acceptable if Tone Gain may be limited like the Marantz 2385 IC. Power Amp is more like the Sony STR-6055. The HT voltage is ±35v, a little down on the ±39v of the TA-1140 so there's the Power drop. Power supply is from a Single ±HT winding if Preamp & Phono use dropping resistors which is a bit cost cut. A single Power Supply Regulator is on the Main amp board. 4700µf 50v main capacitors a bit average for 1973 also. Bulb is a Neon. The design certainly lacks some of the TA-1140 quality if typical with Sony it's very shy of Bass if they upgrade well, to wonder why they limit bass, even the STR-6120 is. Fully Complimentary with Doubled-Parallel outputs if on small TO-220 size transistors with spaces for TO-66. Power Supply is basic, it just has one transformer winding for ±35v main HT for the output transistors & the other stages just pull from that via dropper resistors which is a bit mediocre. Pity the Service Manual is still the Poor 3rd Gen Photocopy, the amp did sell well if maybe only getting Respect now? The 'Ripple Filter' on the Power amp is confusing on the circuit as it only apparently powers the L channel if the R one doesn't have this which is illogical. But to look at the board track it supplies both channels, so the circuit diagram has errors. Anyone notice that before? First Try As Unserviced. Not heard one of these since about 2007 & we did keep the TA-1130 we got after as the sound was preferred, if neither were Recapped in those days. 'Pro Seller' still left it on 220v, adjusted to 240v. Would also help if the Tone Controls were fitted to set flat correctly. Has the similar Volume to other Sony where Volume is tapered more if it's smoother in Volume than the TA-1140. Sounds fine for a Raw Amp, quite Trebly that the TA-1140 wasn't if the Ceramics can be heard, or is the IC? Playing Rock it generally does it well cranked up Louder if it's not got too much Finesse to it. Heatsinks a little warm tells it needs Servicing if overall it's noticeably Better sounding than the TA-1140 as a Raw amp despite the IC it has very low NFB overall to sound fresher. This sort of Design is actually more Mid 1970s if it needs better spec to bring the real sound out & luckily we bought one despite IC reservations so will try to upgrade it more as the TA-1140 got tried. Opinions on Forums say this is a "McIntosh Killer", oh for more in-depth opinion than that, but based on McIntosh we had it's away from the slower sound that even the TA-1120(A) has, if the STR-6120 is much fresher sounding. Being Cruel In Amp Comparing... we did a test of 5 upgraded & recapped amps & then thought to see how this amp did as Raw & Unserviced. The smaller sound of an original amp, Bass & Treble extension lacking very obviously, but listen beyond that & the TA-1150 actually sounded very decent. One we'll upgrade if only by trying more as we did with the TA-1140 we'll maybe find it's limits. Didn't sound rough or grainy, quiet background & sounded quite fast in dynamics. The Best Sony Integrated Amp? It's still built to a budget, voltage drop resistors if no Zeners is never a Top amp, the ICs, some low spec from cost cutting & quite a bit of unshielded audio cable similar to the TA-1140 means it'll upgrade nicely, but not one to go too far with. Looking To Recap & Upgrade, the opinion was "there's not much in it" compared to how complex the 1965 TA-1120 is. The IC itself is shown on the manual, it's basically 2 Op-Amps & a 'Bias Circuit' which is actually a Voltage Regulator, all in one case. How good the IC is we'll test if it seems weak supoorting design is more the difficulty with these more basic ICs, so to try another IC amp after the Marantz 2385 seemed worthwhile. This amp is earlier than the one we had years before, the drop-voltage resistors are only 0.5w & look like they've got hot to look aged so the later ones have the bigger ones that are inaccurate, cost cutting as is the main power caps just the height to fit in. Mostly Recapped except the Power supply ones if done the Preamp ceramics. it sounds good, wide Stereo, too early to give a deeper opinion. Dynamics are lacking depth if it sounds lively, not the fastest sound if still in the style of the TA-1140 & STR-6055 upgraded recently. Volume needs to go up to '5' as is typical with Sony & after that it gets louder with less slider movement as by '6' it gets quite loud. Now All Recapped. Now a Punchy Fast Sounding amp, if still a little restrained not giving the sweet open sound, if otherwise clean & clear. Putting in matched 820R resistors does make a difference to detail. Very quiet background on the amp. Stereo is very wide if Bass is modest even upgraded. The Low NFB design is quite different to other Sony & gives a fresh sound that to see if it could do better. Now run in heatsinks a bit warm so to Bias. It's one we'll test on the Oscilloscope with Square Waves & put on the Blog page, as we did testing two Marantz 2385 & 4070. Bad Problem. In the interests of keeping this amp alive as it is a good one, the Power Amp adjust pots on ours were locked with paint as typical. Trouble is the new type of pot soaks the paint into the adjust track area & if you adjust bias the paint will break connection & naff several transistors as we found out. Ours we tidied & found they tested correct, if a job to do. Final Verdict: The TA-1150 is not a lesser amp for the ICs at all, we tested it as we did with the Marantz 4070 amp & it tested even better, no limits at all to the design. the Power amp is the lesser of the pre & power, an odd design to use Doubled Outputs if more to get 35w from 25w transistors. But hearing how good the TA-1150 preamp was, we decided to try more with the TA-1140.
BUY-RAW RATING: Good, if usually full of dust & dirt. Often way overpriced on ebay though. Beware the Bias pot issue. COOL RATING: 7 sliders & push buttons lose some of the style of early Sony if still purposeful & easier to use. (2007-2018-2019)


1973 Sugden A48 Mk I amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 40w.
FC, if no DIFF. the only FC or SC amp beyond the 1960s ones not to have the Differential. A very sweet UK made amp but too polite sounding & a bit ugly looking with the wood case looking like a Leak one & a bit cheaply made. Very Good phono stage, but for 40w doesn't kick enough for us. One of those amps that could take some smart upgradeing to bring more out of it, the design is tidy if a typical English sort of design like Ferrograph if much better sounding. Hard to recap as typical UK style axial caps. Of UK brands we tried, Sugden outdid all noted here (Ferrograph, Radford, Leak etc) for the fine sound it delivered, perhaps could improve up but with the axials. Beware the odd presets on the tone board that need fine adjusting with test tones or the sound balance will be wrong, we never tried to upgrade ours any further. Beware of fools replacing the volume control as it loses the power switch, it's not faulty. So many of these & the earlier Richard Allen ones have been ruined by those who don't know they were made only to give a better volume at half-setting as the user booklet states, don't mess with them. We bought a new set of original push buttons from Sugden, but they said supplies were limited at the time. But no denying Sugden were much better quality than Leak, Rogers & similar UK brands at this time. The amp turned up on ebay Feb 2017, buyer made a modest profit. We've not bothered much with UK amps since if did try a Goodmans Module 80 again. UK hifi always has a crappiness to it, years behind the quality of Japan & USA amps, low spec grainy sound & axial capacitors. Even Rogets Cadet III & HG 88 III were never high-end type hifi. Past 1980 Sugden continued & made amps that are popular, if we've yet to try any. HFE site has very little service info & later Sugden are in the league of Musical Fidelity if hopefully better quality inside. It's just the unknown with UK hifi & knowing the general crappiness of the 70s brands. The recent Sugden A21SE is a 30w Class A amp, one on ebay for £2200 which we've already proved with the Yamaha CA-800 II that Class A makes no difference on upgraded amps. You're buying an expensive hot running dream. BUY-RAW RATING: Good if it needs the tone board inside pots properly calibrated & beware volume control replacement. COOL RATING: 3 very plain looks in average quality case didn't inspire us to use it much, really not good enough. (2012)

1973 Trio-Kenwood KR-6340 Quadraphonic Receiver ↑
AS-ORIGINAL (Once Serviced): Average-Very Good. UPGRADED: Excellent. 2x 50w + 4x 20w. 4ch, Bridgeable, Diff, SC. For finding the 1973 Marantz 4070 Quadraphonic Receiver interesting & great sounding, to try other brands. For some reason there are 5 in the KR-x340 series of very similar power. Our ratings are the correct 1kHz power rating for 8 ohms, ones elsewhere quote the 20Hz-20kHz one which to us is meaningless as we'll upgrade them, so the 1kHz only matters. KR-5340 is 2x 30w + 4x 12w, KR-6340 here is 2x 50w + 4x 20w, KR-7340 is 2x 60w + 4x 22w, KR-8640 is 2x 65w + 4x 27w & the KR-9640 is 4x 44w only. These are Bridgeable like the Marantz are to give a proper Double Power plus extra, if some brands don't use the Bridged design. we'll blog more on 4ch amps to see others that could be worthwhile. The 6-7-8 models are so close in power it shows Trio were believing that Quadraphonic would take off, but too many formats so it failed. The amp covers RM which is Regular Matrix that creates 4ch from 2ch by phasing which explains on 2ch why one channel is louder, also SQ is built in, if the CD-4 version needs the optional adaptor. These amps apart from in the USA are always minus the plug-in 4ch Matrix decoder as they were sold off in discount Stores & didn't sell in the first place. Some buyers got a great amp with the Bridged Design. The KR-6340 is bigger than expected 555mm wide, 360mm deep & 160mm high at 15kg weight. Styling is like the KA-6004 1972 style with the plywood & wood vinyl effect sides. 4 channel is the Amplifier only, Tuner is 2ch only as is Phono unless you use the Decoder for whatever system it used. "Two-Four Receiver" says the front panel & when on the Tuner is a subtle green light with a Tuner Signal meter & a light for 2/4ch amplifier mode. The bigger 7/8 models added needle meters. The KR-6340 is all Transistors beyond 3 in the Tuner. No User Manuals to see what the extra buttons on the higher models do, if the KR-7340 schematic shows Filter Switches, the KR-6340 is a rarity in having No Filters which is great as the Circuits can be a pain as they limit, the KA-6004 has transistor stages in both, the KR-6340 has none of that. KR-6340 has FM Muting & Loudness still. The only listed 4ch Amp by T-K is the KA-8044 which is an early 1970-71 capacitor coupled design based on the KA-6000 with "Surround Sound Quadrix Amplifier" containing a Reverb section, if 4x 24w only. Design & Comparing the KR-x340 Range. Tracing the very complex circuit for the 4ch design has Phono as 'Preamp' as it has MPX output Tuner & CD-4 Decoder stages amplified through it, if not the Aux input which meets the Tape Monitor input before Selectors & Volume control. Volume goes to Tone direct, no nasty Filters here then a Gain Stage & Passive 4ch Tone with the Ground reference design, not a Baxandall type. The KR-7340 filter is a very basic one on it's '20dB amp board' unlike fussy ones on the KA-6000/6004. Then to a 2ch/4ch mode switch on the back that changes to Bridged & alters the Speaker Outputs to the Hot/Cold for Bridged Mode, then to the Power Amp. A SQ decoder like the Marantz had is built in. Less circuitry in this bigger amp than Marantz stuffed into a much smaller amp. The Tuner stage takes space if new smaller Tuning stages reduce space taken & underneath the main Tuner board is a big space for the 4ch Decoder, or to hide some bars of chocolate as it's the right size. Transformer near the front with 2x 8200µf 35w main capacitors on ±27v HT which is up on the ±24.3v of the Marantz 4070. Power Supply board for the main HT is a full wave rectifier, if 2 diodes underneath & 2 on the PS board is odd. Power Ratings will be modest for the spec of the design if the 35w Marantz could easily 60w from our readings & this KR-6340 could go to about 80w bridged. Damping Factor on 4ch is a very low 20, so in Bridged Mode which halves the Output Impedance, it'll be 10 which will sound good. Power Amps come as a plug-on module with the Output TO66 2SC1444 on small heatsinks, actually rather small for the 50w rating, but in reality it's a 20w amp x4. Progress in transistors loses the huge TO66 the KA-6004 has & here the small Driver transistors take up much less room to fit a Stereo power amp components into 106mm x 77mm size, not including the Output Transistor area, who needs ICs? The KR-6340 Power amp design compared to the same one the higher models use shows the KR-6340 has a Buffer stage on the Front L+R stages which has the Bridged input also, the higher models probably use the 20dB amp similarly if on 4ch. KR-6340 is Semi Complimentary, the higher models are Fully Complimentary with minor design changes to suggest they are slightly later amps. The KR-5340 & KR-6340 despite big power differences are the same in many ways, same HT voltage & Power Amp, yet 30w & 50w x2, current capability the difference with lesser spec elsewhere. Relay Circuit, with a 4 channel Relay, on it's own board unlike the KA-6004 which cramped it onto the Power Amp. Underneath is the SQ decoder board & the big space for the KCD-2 which is the CD-4 adaptor. As with Trio at this time, there is a lot of unshielded cable carrying Audio which may not be so bad on short lengths. Here only the Tape wires are unshielded on longer lengths, the KA-6004 had lots on the Filter Stages. The KR-6340 & the others in the series are very impressive & 4ch amps led the way to make better amps in the mid 1970s if then the Cost Cutting spoiled what should have been improvements. Sound As Original. Amp was dusty inside but not much sign of use, bulbs all light, Tuner FM/AM works. Sound on Headphones as only lightly serviced is Crisp in both 4ch & 2ch modes, only 1 adjust pot per channel here, the Marantz had 2. Lively sound, Wide Stereo. Plays Rock with adequate Focus if not much weight to it Bass-wise. Fast Sounding amp that does well for an original amp if gets tripped up by busy tracks if nearly all amps do, busy Ska Horn sections are not delivered too well. It certainly has the Basics in Sound, Design & Build to be an awesome amp & a little easier to work on than the Marantz 4070. To Recap a Quadraphonic Amp is double the work as 4 channels. These will still be ignored & low priced as ours was as no-one has bothered with these until us, so grab one if it appeals whilst they are cheap. Considering the 'raw' Marantz 4300 with 2x 100w 4x 40w is a £1300 buy, this as a 2x 50w version is great value. Our Rating of 6340 & 8340 would be 'Very Good' if the real Lack Of Bass gets them downrated as No Bass won't please, but it's in there to upgrade. Sound As Original on Speakers if just lightly Serviced sounded very decent, the Low Damping Factor Bass like the Marantz 4070, midrange on voices was spot on. The 2ch-4ch mode on Speakers gave the same gain as the 4070. But it did show it needs a proper service & recapping as the L channel didn't stay the full volume, going to the half volume like 4ch mode, so not to try for long if DC offset was fine on testing. The Screw Connectors you can only really use the 'Y' type connectors, to put the Gold 4mm blocks on it was a bit dodgy & needed some electrical tape just to be safe, It needs 16 of the 4mm sockets. To try the 4070 on speakers shows the upgraded sound & the 4070 isn't going anywhere yet, it sounds awesome, if sold since. KA-6004 compared to KR-6340. As this is the 4ch Receiver cersion of the KA-6004 in some ways, to see the differences. Tone as stated already is different, 6004 has a Buffer, Tone Stage with NFB round the next Transistor. 6340 Tone is Passive after a Gain Transistor. 6340 has no Filters. 6340 Power Amp after the Buffer Stage for the Bridging Stage, the Differential Base load pairs differ, 6004 has an extra transistor for Bias the 6340 doesn't else much the same. The KR-6340 is more satisfying to us for the Bridged Mode & no Filter that is a bit much in the 6004. No Pre Out-Main In sockets on this amp limits comparing, to assume pre-power is the 100mV level of the KA-6000 not the 1v of the KA-6004. Only to compare both will tell which is best, beyond the Bridged Mode advantage. On looking at this to work out the Amp to Upgrade, how much there is in this Amp. The Marantz 4070 didn't work if this does so to consider it deeper & see how advanced the design is compared to the KA-6004, new ideas used for the first time as well as new TO126 size driver transistors to put a 2ch Power amp into such a small space & still have the Resistors flat to the board, not cramped on-end like the KA-6004. The TO66 output transistors are 40w 6A ones which is high power for the TO66 size. The Circuit has a 2ch to 4ch "RM" board that thankfully is bypassed until selected, it creates a pseudo 4ch effect from sound shaping & phasing if on 2ch it just makes one channel quieter. still has typical resistors in the signal path for coping with unshielded audio signal cable. Takes a while to understand these amps when they are new types of design so let it sit a few days. Recapped-Upgraded on Power Amp is the first job we do, these unplug so a lot easier to work on than the Marantz 4070. Without re-reading the previous opinion yet, sounds very decent, clean open sound. One heatsink gets warm & the 2ch-4ch mode shows 4ch is just a little crisper, so needs Biasing. Sound is upfront with better Bass if still more to redo. The focus on sound is improved on the dense 60s Ska tracks if still gets a bit messy. As with any upgrade, it's the sum of All Sections upgraded, not just one. Biasing. Not as easy as the Marantz 4070, there are no Test points, so to read across the back of the Upper white 'tooth' output resistors. Set it to 4ch Mode, ours showed Bias was originally too high. 4ch amps do differ from 2ch amps & the Bridging has certain needs that we worked out with the Marantz 4070. Main Caps Redone. This brought the Expected Bass back to the amp, it was rather thin before on both Headphones & Speakers. As the years go on, we're finding more Big Caps are below what they should be, in Nov 2018 the Rotel RX-1603 & Yamaha CA-1000 both had bad caps. To say a 1971-73 amp we have sold before before recapping was still fine, another few years goes too far in aging. On 1967 Tannoy Speakers it has that deep Bridged Bass as the Marantz 4070 does, Treble is Clean, but not quite a match as the Midrange is a bit too upfront, a similar sort of sound the Realistic STA-220 had if it had a Midrange control to tame it. Would suit later speakers better though. Another Interesting Amp for sure, but as we use some amps on Speakers in rotation, this wouldn't be one we'd keep. 4Ch power vs Bridged 2Ch power. The Marantz 4070 15w/35w doubled the Sine Output Voltage & this at 20w/50w is 19v 4ch & a hefty 39v 2ch Bridged that puts it in the league of a 90w amp, the reality is it doesn't have the reserves to be a True 90w Amp if it's 50w is clearly underrated. 2019-2020 Further Upgrades. After hearing the similar sort of sound as the 1967 JVC 5040U on cpmaring amps we had later 2019, the KR-6340 needed further upgrading, to see how good it can be. Upgraded rather a lot on rephotoing it to sell, a Extremely Decent sound now with Real Bass & Fast Dynamics. We've finished it so to sell as we've done with other amps we've further upgraded, if the buyer will have 'One Of Our Best'. To do a bigger sized 4ch Bridgeable Amp than the Marantz 4070 was an interesting one & now after Blogging more on 4ch, another Amp will get the treatment too. BUY-RAW RATING: Generally Good if 45 years old now. COOL RATING: 7.5 big purposeful looks if lacks the meters of the higher models. (2018-2019-2020)

1973 Trio-Kenwood KR-8340 Quadraphonic Receiver ↑
AS-ORIGINAL (Once Serviced): Average-Very Good. UPGRADED: Excellent. 2x 65w + 4x 27w. 4ch, Bridgeable, Diff, SC. This is a Higher Power version of the KR-6340 just above. These High quality Receivers sold very few, the 8340 a customer could find, but the KR-9340 seems unfindable, if it's a 4ch Receiver only, not a Bridgeable one. You can see we highly rated the KR-6340 but only after a lot of Redesign to bring out a proper bass. The 8340 has a Baxandall type tone wheras the 6340 had a Passive one that wasn't well designed. 6340 still needed a lot more redesign to get the sound ours has now. The KR-8340 is a great looking amp, 1973 seems to be the last "Good Year" for many brands before Cost Cutting until higher models arrived 1975-77. The KR-8340 has extras to the KR-6340, Output meters, Muting for FM & High/Low Filters that are not problem design ones/ Extra Rotary controls are 4x Bass/Treble control as the lower right ones plus 2 Balance controls for the 4ch. Rear shows there are 2 sets of Tape with Front & Rear, assuming you had a 4 track open reel tape. To a 2019 buyer the Delight here is 4x 27w means 2x 65w bridgeable which once upgraded is a lot more as the KR-6340 proved. The rear shows it's later than the KR-6340 as it has Spring Connectors for Speakers & a Push Button for 2ch/4ch mode. Rear has a space for the Decoder as does the 6340. No Pre Out-Main In connectors on this if the 1973 Marantz 4070 does. AC outlets covered with a Blanking cover & a Multivoltage 120-220/240v switch. Antenna on this was used as a Handle & a different one fitted if it can be tidied to look ok. Inside shows it's a later model than the 6340, the Selector rotary goes to the back of the amp to keep things tidy, if there are sections near the front for Phono & Tuner. Power Supply is tidier than the 6340 with a long board with Relays giving the amp the extra width. 15000µf 35v main capacitors is a very high value for 1973. Big Transformer looks an 80w-100w size. As with the 6340 quite a bit of unshielded cable on Audio that may seem less good but knowing the 6340 & how it needs care doesn't limit the sound at all. Power Amp Board. This will be interesting, it's a 4ch Amp on on one PCB of 210mm x 80mm. The PCB plugs into a strip & held on with 3 clips. Heatsinks are 2 rows with Complimentary TO3s with metal sheilding between which is unusually good. PCB we'd think would be very cramped, it has 8x TO66 drivers on, 2SA652 & 2SC1161, but it's laid out neatly with no compromise. TO66 transistors are more 1970-72 design, if the earlier apparently later 6340 uses smaller ones. The Power Amp board is pleasing, but how quickly top build & design went to ICs with Trio-Kenwood, these 4ch receivers do seem their best product. Underneath. This brings a "Wow" as the build quality here is very impressive, big solid chassis & line of Plug-In blocks for the Power Amp push-in slot board. Complex 2-4ch Rear Buttom has simplified the Rotary selector. More Power Supply below with the 4ch Effects & Phono board. The front PCBs are very packed, the 4ch Tone is all on a 100mm x 80mm board tucked right in the front. a centre front board has Meter & Filter with the Heaphones board having Circuitry. To Upgrade This. Knowing the KR-6340 the underneath front boards will be difficult, how much needs taking apart? Power Amp unplugging eases things, but underneath it is very packed. Preamp is like the KR-6340, Aux goes to switches to Pre-Tone, the SQ-RM boards are bypassed. Tone is a Baxandall design unlike the passive KR-6340 one which wasn't so good as original. The Front Preamp needs the whole front taking apart as 19 plug-in cables. Tone board can only be got to apart. Not Tech Friendly at all & a 2 sided board like the KA-6004 preamp that looks bubbly soldered but is good. Power Supply is actually in several sections for various stages. The Power Amp is ±31v with the KR-6340 ±27v with 65w & 50w in Bridged Mode, the 8340 should do about 100w as the 6340 appears to be capable of 80w. To test power needs 8 ohm test resistor & Multimeter on Power Mode, if to us it's too vague & no Speaker is 8ohm flat, so we do the Clean Sine Output table as on the 'Power Ratings' page which gives better comparisions. 6340 gives 19v/39v which is about 90w rating on Bridged. 8340 gives 21v/43v which is in 110w rating. 20w difference at 90w-110w is very little difference really. Our Rating of 6340 & 8340 would be 'Very Good' if the real Lack Of Bass gets them downrated as No Bass won't please, but it's in there to upgrade. Upgraded & Done. This was a tricky amp, but the results were well worth it, the KR-8340 sounds much like the KR-6340. Used it on Speakers for a Day & the Bridged Sound with Our Upgrades really transforms the Amp. Big Fast Dynamics with Exciting Bass that's clean and not thick sounding. Our KR-6340 has a Passive Tone which was poor so we redesigned it, the KR-8340 is Baxandall NFB style & sounds correct. On Speakers the KR-8340 really comes to life if on Headphones it's not as impressive. To get this Returned before Xmas to Non-UK means we didn't get to try it enough & compare to our KR-6340, as the 6340 needed a little work, if 8340 inspired it & it's been on Speakers again since. Bridged Amps are certainly something special, but they need Upgrading or it'll not sound much different. We'll try more 4ch Amps but only the Bridged ones. BUY-RAW RATING: Unused since 1976 so it'll be tired. COOL RATING: 8 smart larger amp with Plastic covered side cheeks. Impressive looker all lit up. (2019)


1973 Yamaha CA-1000 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 70w + 15w Class A.
FC, DIFF, FET. Our 2022 opinion of this is quite different, lively crisp sound now after some redesign & sounds great on our Tannoys. How different to this earlier opinion. 2012 Opinion. Their first 70w amp with Class A, a warmer midrange balance loses it detail if very clean otherwise, but we got the CA-1010 just as we finished ours & sold this too fast. Takes a lot to get it working right & for this, some deeper exploration could bring back the detail if you like design, we thought it sounded a bit warm & soft even after recapping, if the quality was there to rate highly. The only minus is some boards are a bit cramped as is typical with Yamaha though we've upgraded several now. This was the first Yamaha we upgraded in 2012 as the amp needed a lot of work & led to a whole heap of Yamaha as you can see. One of the better Hifi brands especially in the post 1972 era but pity there are no 1960s ones. We saw our amp later on ebay & thought to get it back to go further with it, but didn't, the seller had agreed it was a bit soft sounding, but it may also be more neutral in comparison to amps we've had since. We should try another one, as the CA-1010 we've found very different. Not an easy one to find though. REVISITED 2018: Long time away from one of these, we did see our first one relisted a few years back, but only now do we get another one. On ebay Buy-It-Now prices on this amp are very high & not selling, where do they guess these prices for Raw amps? 70w amp with 15w Class A puts it into a different league, if we found later with the CA-800 II that once upgraded we couldn't hear any difference in A or B modes, if as original it did show a difference. So we get a very neglected but still sound one just needing a few parts. why these Yamaha amps get a hard life is strange as the receivers usually turn up in nice grade, if not always. Can only assume the less-aware buyer used Class A & thought the amp was about to catch fire so dumped it, but Class A does run hot. Tired old amp soon looks respectable, all amps are a gamble to buy but to have one complete or to get the missing bits easily makes it worthwhile. Inside it's not been touched & the Power Amp board fuses test good, so it likely works, if we'll check it far more first. The CA-1000 is the Amp version of the CR-1000 adding Class A, the Amp boards are the same. We've had varying success with the CR-1000 with it ranging from a poor Speaker match to the last one being a 1975 dated one sounding great, if why is obscure. Amp was dry stored in an attic so no corrosion if glue on front controls failed to lose parts. To realise the owner of the amp who put it away for decades probably grumbled at it as it cost £274 in 1975, but if they don't bother to read the books, their loss & only cleared out by family decades later, at least they saw the worth in it. Years ago it would have gone in a skip. Amp Boards look good so to assume by the Heatsinks being off-black that Class A was used & someone told him to scare it up in the loft as faulty. Maybe the daughter selling got the blame for 'breaking Dad's amp'... it happens. Updated Board. The Function Circuit Board is NA06335, ours is NA06582 with a 6 pin can IC looking item. YJ1200 with 6 legs is likely a Double FET where TR 403/404 are. the CA-1000II circuit shows this Double FET on a later NA06772 board. 2 FETs in one can to have them matched is often seen on later amps, the 1984 Sansui AU-G90X has these on the early power amp boards. Yamaha are notorious for updating boards if the basic circuit looks the same, often number changes are for minor transistor updates as old went obsolete. Getting It Going Again. Very hard to get the missing parts & then find one critical part damaged, but we get there at last. Amp shows signs of life if the ±48v Power amp voltage is way down if the Class A ±18v actually is OK, but no Relay on as it's in need our our work. Otherwise amp in good if aged condition & it'll sing again for sure. The dark brown 'UPS coloured' coating on the steel chassis keeps it from corroding. Pleased to get minor success on this, some amps are a big gamble & this probably one of the biggest gambles & at a price. Bad Caps. But HT voltage way down isn't the power amp as Recapped that, one of the 18000µf 63v big capacitors actually failed & leaked, the mess inside wasn't water damage as the wood lid untouched. The owner must have been a bit dense & put the amp in a tight shelf, put it in Class A always & the amp literally cooked alive until it stopped working right. Never seen a Cap so big fail, if the Pioneer SA-9100 had a big vent hole open if no mess so didn't trust it for a customer. Class A amps will get very hot in open air, but if covered over, your amp will fry. Still allows us to get new main caps if there are no 50mm x 80mm caps made, improvise time & not to stuff capacitors either. Caps this size are 85°C rated so the amp must have been regularly on at 100°C+ to fry. The cap had ventred, if on cutting open the lower end at least was still wet, if the top end was hard sealed in, so to open it more & unravel it showed it was still damp with darkening at the edges of the paper, no sign of anything much wrong, if not to be trusted once leaked. Recapped with Upgrades. This was a tough one to get right as it was left on Class A with no ventilation so it cooked. We first thought in 2012 it sounded a bit dull after getting the thin & bass-light CA-1010 so sold it too fast. We've had 2 of the CR-1000 recently & the CA-1000 is the amp version. Both upgraded sound The Best of Yamaha. They are Professional Sounding Amps, this is not a Domestic Sound, it's right upfront with a precision & detail the more Homely CR-2020 range sound. It makes other amps that are more Domestic sounding seem rather soft in comparision on Headphones. Depends if you want that Upfront sound on Loudspeakers though. 2022 Update. Had issues so it's sat for quite a while, if looking again get it playing right. Certainly lives up to the 'Natural Sound' front panel hype, quite a different sound to the CR-1000. Doing the Bias settings makes quite a difference to how clean the Treble is. BUY-RAW RATING: Good, if a lot of Class A use will age the amp for the heat. A big job to get one of these right if it's tired. COOL RATING: 8 classy looking minimalist pro looks, well laid out, purposeful if maybe a bit stark looking to some. (2012-2018-2022-2023)


1973 Yamaha CR-800 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 50w.
FC, DIFF. A particularly good sounding & well made receiver, punchy wide spaced stereo with a sweet sound and more bassy than Yamaha usually made. This is the 'easiest' Yamaha to buy & use just serviced, with a high quality sound balance from buying one all-original. Not as loud & upfront as the CR-1000 and actually more listenable to for a longer session we found using headphones on our upgraded one. Getting another one later after getting amps like the Nat-Pan & the Marantz PM6002, this still does sound a Very Good amp & without the loud CR-1000 to compare it too by itself it certainly pleases, treble is detailed and certainly not lacking punch on Rock. Trying it unserviced it was warm & a bit raggedy sounding, but after it tightened up the sound very well. Pity it's only a vinyl wrap case, though to reveneer in teak or the CR-1000 type american walnut is a nice idea. The USA 117v version and the one with the 3 mains outlets & 190w noted is vinyl wrap too sadly, they all have the same veneer pattern. But there is a rare DIN sockets-only version with added German wording. The CR-800 builds on the CR-700 sound and is much better built, this is/was a bargain amp for how good it sounds. To upgrade & recap this was too tempting & we'd like to go further still knowing it's the Yamaha we like best. The result was in the league of the CR-1000 & CA-800II if a fuller bassier sound than either. The only minus with Yamaha overall is they don't match to all speakers, the pre 1975 Tannoys don't match many. As you can see, it was our favourite Yamaha amp as of 2014. Playing a Serviced but Original one the sound is bassy, reasonably crisp & lively if lacking a cleaner focus. Treble is typically fizzy on loud Rock as most amps are for the cheap ceramic capacitor which we upgrade to film. In comparison to the competing Pioneer SX-828 & SX-838 this betters them, as based on all original. Unlike the CR-1000 below, this was a Very Good match to the Tannoy Golds which was unexpected. Recap & upgrade later, it reveals a clean sound and sounding more neutral than the bassy original sound with cleaner focus & a good punchy sound that is not tiring. Of all the Yamaha amps we've upgraded as of 2014, this is capable of the most neutral sound. REVISITED 2019: Not had one of these for a while if did have several before 2011-2014, now it seems a better amp for having known many more & well built. The one we get to Upgrade is the EU DIN version. DIN version has Phono 1&2, Aux, Tape A&B with a Rec Level switch as DIN Tape Out can be too low for some machines. 'IF Out' is an added one, Tuner related output for DX-ing probably. The User Manual shows Types A-E but not the DIN one which was probably sold in France & Germany etc, rare in UK if the standard one over there. Pre Out-Main In is DIN too of limited use. Speaker outs are the DIN plugs & it's Multivoltage. Rated 190w as are other versions if the Type E one UK got is rated 450w somehow. Fitted with 3 core mains with a round pin moulded plug with E contacts. Looks much the same inside if the DIN version has what the others should have, a nice moulded plastic cover for the main capacitors. The Power Supply board underneath & the very cramped Preamp board at the front are both hard going on this amp to recap. HFE still only has the blurry circuit manual, why no update? Play as Original. Some amps age better than others & the CR-800 we always had working ones if that's now 4-6 years ago. This one works, LED bulbs in by a previous owner. Sound is quite decent overall, Bass won't trouble you if the midrange is clean, Treble isn't bad if a little blurry, a bit soft sounding as we thought before if still quite punchy. No longer a cheap amp, the CR-800 is in the league of the CR-1000 in some ways & knowing the CR-400 that's quite basic if good sounding, the CR-800 is still a Quality amp. Packed fascia with controls a bit close perhaps but still one of the Best Yamahas especially compared to the CR-820 where the CR-800 quality is long gone. This is a later 1975 dated amp, with the top lid grille without the screws showing. As with the CR-1000 these do vary in sound, the earlier ones we found Bassy & Wallowy, here it's fresher if Bass is not really there. Recapping. Yamaha are hard going to recap on all of the higher model classic Silver 1973-77 ones. The CR-800 has a cramped power supply if it doesn't run too hot, it still has regulators that run warm. The difficult part in this amp is the front Preamp board which crams Microphone input, Tone Control-Preamp & Filter Amp all onto one board. The CR-800 manual you'll find is awful as low resolution still & to try to work it all out is advanced, as well as space is limited. It's got lots of Ceramics with no space to do much else unless buying expensive ones & for having done one fully, perhaps it wasn't so important to do as the CR-800 is a good Domestic sounding amp if not as crisp as the CR-200 or CR-400.
BUY-RAW RATING: Good. Needs a deep service to sound it's best else it's a bit too soft sounding. Bulbs are usually in need of replacing. COOL RATING: 7 the classy Yamaha looks if more friendly looking for domestic use, if loses a point for Vinyl wrap we later decided. (2014-2019)


1973 Yamaha CR-1000 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. 75w.
FC, DIFF, FET. Rewritten 2017. Great amp, the first vintage Yamaha we got in 2012, but is a very upfront one that may not be everyone's taste & later versions do vary. It can sound very hard & harsh with not much bass as original, it can be a poor match to speakers also. It's one of those amps they dumbed down too much, if upgraded it is truly excellent. The best of the 1973-78 Yamahas to us, if only once much upgraded, read on. On getting an earlier serial number it reveals there are several versions of this & the power amp board has numerous versions, the sound on speakers does vary. A 1900 serial matches pretty well to early Tannoys, but the later 4400 serial was very dull, even with tone not used. The NA6401 is the original board, our 1900 serial has the NA6402 if the 4400 serial with the CA-800II design phono stage has a NA6408 power amp. Buying an all-original one needs a deep service to sing it's best to give an extremely revealing upfront Pro sound that will shamelessly reveal post 1975 era speakers & any headphones as being inferior or a poor match if it sounds hard. Before servicing it always sounds dull, soft & nothing special & we've had four now. A big upfront kicking sound best suited to a big room: it is strong, accurate, tight bass & impressive but a louder sound than most domestic amps & is great at resolving music to the right master level, but can be overpowering too as a more Pro-Sound volume than Domestic Hifi sound the CR-800 is. It can be quickly tamed if required just with the loudness slider to mellow it back so you can have a more domestic balance at 3-5 on Loudness, if then it loses fidelity. It is one of the Best Built of the amps we've had & after going very deep into the circuits, we found the upgrade potential of this amp is very high & later see there is more still in it. After the pretty average 1969-71 Yamaha, the step up in quality is huge & will have set the tone for other manufacturers. The regulators still get a bit hot like other Yamahas but can be altered. Our top Yamaha also for the looks & wood case. One minus is the input phono sockets are thin plated grey-ish gun metal on copper & usually found a bit crusty & not really upgradeable as fixed to a plastic panel, if can be polished to a lighter colour perhaps if the plating is thin, also the mic slider must be set to off as it has a wide variable gain & with nothing plugged in it's noisy. There are 2 phono stage versions, the later 7 transistor one is decent after some minor changes. Phono stage with the later NA06460 board delivering a clean detailed sound without the Bassy bloom of most Phono stages. The reason why Yamaha could make their superior 1973-77 range we found out by seeing a 1972 ad for the CR-700 etc. They wouldn't have their products put in the discount stores, but Pioneer, JVC & Akai did and so became heavily cost cut. The sound of this amp is close to the 1973 Realistic STA-220 if that's still a capacitor coupled amp. A wise choice, if Yamaha had allowed Discount Stores to get their 1971-72 range, we'd not have got their Classic Ranges. The odds of this receiver existing if it wasn't for the Pioneer SX-828 is interesting. These amps are what started the Receiver Wars, if some of the 1967-68 ones above are comparable. As with the CA-1010 below, the Pro-Sound volume & it can sound 'Clinical' on the wrong sort of small speakers as you need 15" ones & ones later than 1975 to do the sound justice. Buy it to use right & Excellent it is, but it could be too loud or mismatched for most speakers is the serious caveat here. REVISITED 2017. One we've not had for nearly 3 years & for how poorly it matched our early Tannoys & for the above opinion of sound, this is needing a revisit. This is a much earlier serial number than the 4xxx first one we had & the one in the Gallery pics. This is an early 'General' model without the AC outlets, if it multivoltage & has a proper factory fitted 13A 3-core mains with a 2 pin+Earth fuseless EU plug, instead of the skinny 2-core most have. Also the pretty useless FM aerial that is like Digital TV on this is the more typical 75ohm TV aerial type, plus other options. This being a 19xx serial has the earlier 12 transistor phono stage NA 06368 compared to the redesigned 14 transistor one, an alternate manual does show the later design introduced from serial 3031 onwards. The input Phono sockets on ours aren't crusty, but whatever thin plating they use over the copper base, as we've found before, always ages, here they are dull grey. Still one of the best looking receivers ever. What does it sound like to us now? Beyond transistor hiss that is another issue, it is an upfront sound & not too unlike the Realistic STA-220. The upfront sound is precise but it's a bit scary for how upfront it is, compared to softer more Domestic sounding amps this is a bit much, but intriguing too for it. It delivers Rock well for this upfront sound. Unserviced it doesn't have so much high treble or stereo separation if bass goes deep. After knowing the 1984 Sansui AU-G90X this does have ideas of sound that 130w amp does, if that's not everyone's idea of hifi as it is a little too upfront in it's presentation. We have the 1975 "The Yamaha Collection" catalog that shows this & others. By this time the NS-1000 100w speaker is available & it has to match the CR-1000 correctly. Sadly one to buy by serial numbers or alter the circuit to the orig spec, if possible. The amp rates 70w but the clean sine rates 90w, so to see the early NPN-PNP output transistors are just 100w rated is a similar sort of issue the 1975 Technics SU-8080 has, simply as technology on these was still early. To rebuild each board & test it to see how different it sounds, checking the boards are the original number ones or to see what they changed. One board done, hiss not solved but reading the above it sounds very different, much more detailed & open sounding, if certainly has the kick it had before, if more sophisticated. We played the Trio TK140X earlier so have that as a reference. Enjoyable listen actually, more in the style of the Realistic STA-220 & it's precise sound, which is why we wanted to try this one again as that's been on the speakers for a few months now. Next board done, solves some hiss if not all of it. Sounds very different again, the reasons why we design-upgrade to bring the best out. Now it shows up the power amp with it's weaknesses if it didn't really show before. The hardness to the sound eases back further to reveal the real sound, it appears more than a few amps are designed to perfection then dumbed down to 'not be that good' to sell & be more universal in use. Playing Rock it's very clean if the ultimate power of it is not quite resolved yet as it gets a bit untidy. The Power amp NA06401 is exactly the same as the CA-1000 NA06331 except for the few Class A extras. What they altered over time is what lessens the compatibility with speakers, our NA6402 will be compared... The only difference 6401 to 6402 is a transistor changed as obsolete, one capacitor altered & 2 labelling errors noted on resistors if all are the same & one board labelling error, another error is on the power supply, a line missing no less & apparently preamp voltage is virtual as it's not connected to the power supply at all. We've upgraded ours a lot & fitted LEDs for the bulbs which suits well here, see the Mar 2017 blog. The harshness gone as it's been very opened up in sound, a very rich bassy sound with high detail treble is really all you'd ever want from an amp. But not quite... the Preamp having the Volume early on leaves a hiss that sounds on 95dB speakers. The CR-2020 solves this by having a five gang volume control including balance, so 2 volume controls at different stages operate together. The CR-1000 tries to de-hiss by putting the FETs on the Filter board. Some amps have the volume before the Power amps, this means the Preamps are running at full volume even with Tone which is hard to stop distortion. Our skills into a tricksy amp is the result, to review the upgraded sound is a little beyond an amp review. But there's always a catch, the Volume control comes early on in the amp stages so it has a background hiss that is slightly audible on 95dB speakers, but on speakers the sound is very impressive. 4mm plugs onto our plug-short wire blocks, never to alter connectors if they can be used in some way. Very precise sound one much upgraded, it's not a domestic sounding amp as the Realistic STA-220 sounds much more polite on speakers, the CR-1000 is an amp to annoy the neighbours with. To upgrade as we've done is a very involved job, but it's one we wanted to finally get right after learning skills with other amps. We suceeded. Now what? REVISITED 2018: We get one to upgrade, all goes as expected, if then trying on our Tannoys, this one matches very well. The CR-1000 was made from 1973-75, the one here had a "7514" code on the Tuner Box inside, 14th week of 1975. Others we've had vary through the run & initially we had written this amp doesn't match Tannoys but now does. even with Tone Off, the CR-1000 this time sounds right. The Power Amp board here is NA6608, quite later than the numbers above, if the board looks the same so what did they alter? Have we found The Answer here...? The later Manual with the Revised Phono still has the NA6401 or 6402 one. NA6608 has exactly the same resistors as NA6401, has the same transistors with TR602-603 as 2SA572 if 2SA763 has been used for earlier amps. So what's the 6402 to 6608 difference, just them finally updating an old number change. So much for finding out why these differ, could just be ones less used as the 1975 one with a dark case is. BUY-RAW RATING: Good if needs deep servicing to bring it alive. COOL RATING: 9 serious kit, high-class looks if rather daunting looking with sliders & switches aplenty. (2012--2017)


1974 Leak 2000 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 30w.
DIFF, FC. A capable, decent lively sound & much more reliable than the Delta 75 receiver, as with most Leak good midprice-quality value & readily findable. Also sold as 'Wharfedale SXP receiver' with a different fascia but same innards & back. This is the one we'd best suggest as a Good Budget Buy to start into vintage with, if the Leak 30 or 70 are similar sounding. It'll not better a Yamaha of the same era in any way, as the rating suggests, but for the price these sell for it's a wise buy. The only weakness are the silver paddle switches like on the Delta 75 that can break. Build quality is much better than the Delta 75 and after 40 years it has survived far better. As with the Delta 75 there are many design changes through the run including a rare black export version. Various fiddlings with protection & putting polystyrenes in the early ones as well as the DIN sockets being in a line or staggered. It has a strange bridging feature to make 30w stereo into 60w mono. An amp that tries to appeal to too many with the extra features. The display sometimes is too dark unless the blue plastic has aged darker with more use. The fascia bizarrely comes into many pieces, as not one piece. A basic phasey surround feature too isn't much use either. The silver paddle switches grow bigger as do the teak sides shrink as the run went on. REVISITED. Got one of these a few years later, 2015, just to see if it's worth upgrading more. We had a few of these early on but the "Recommended" rating as upgraded is quite old now as in 2012. We tried a Leak Delta 75 again so to try this is worthwhile. Still all UK made but looking inside it is well made unlike the D75 which is a random mess. Amp on top board, tuner on the bottom, preamp-tone on the front & modular in construction. TV grade capacitors as noted before if quite a few expensive polystyrene capacitors in the Phono stage do show quality. Of all the UK amps we've had, the build quality on this is in the league of the Sugden & to trythis one instead of a Goodmans Module 80 was preferred as the Goodmans is a bit crudely made. First try of a long stored one shows a good Service is needed to sort user issues. The sound is adequate if far from from Hifi after servicing but does show it's not bad either. There is a smoothness if a grainy sound too from low spec as is typical with UK hifi. The sound isn't too far different to the Delta 75 we tried a few months before as a revisit. It does have a bit of kick to it on hard transients but on Rock it's not got the drive, if few transistor amps can reproduce the Marshall valve stack sound well, this can only but suggest it. Probably why this one has had so little use. We'll bias it once it's run in as it gets a bit warm & this affects the fidelity. The main transformer is quite small for 30w into 8 ohms, 35w into 6 ohms & 40w into 4 ohms, so we'd not think it could be upgraded too far. Outputs are fully complimentary if the manual doesn't give the codes, the transistors show 'M 441 Z 189' and 'M 504 Z 188' which is unfindable, the manual shows '504.09' and '505.03' equally useless Leak codes, if these rarely are found faulty. Bias is way too high always so it runs hot, the manual actually states 90mA, we ignore that & it runs cool. It's still a very decent budget-midprice amp, it has enough quality & power to please many users, if not in the high league, but as we found before, doing too much to it outprices it, so we'll just sell it as original as it's reliable & tidy. Our previous upgrading was only recapping, so as it's not being upgraded to our current standards, we'll revise the ratings to what we hear today. LEAK 2200 AMPLIFIER is basically the 2000 without the tuner board & 45w supposedly, it looks the same board as the 2000 if maybe higher voltage for 45w not 30w. Looks a bit random on the outside as it tries to use as much of the 2000 parts as possible. HIGH POWER MODE. After getting the 1973 Marantz 4070 Quadraphonic amp in 2018, to learn how the 'Bridged' design works. The Leak is a simiar idea if a very different design where the output of one channel goes through a 820k ohm resistor into the input of the other channel, they clearly didn't know of the reverse-phase idea & this design doesn't sound a good idea. BUY-RAW RATING: Good, needs a good service for rough controls. COOL RATING: 6 some style of the era here on the teak ones, a bit Legoland with the buttons, but in all-black as export ones are, it looks very odd so only 4. (2015)


1974 Pioneer SX-1010 receiver ↑
AS-ORIGINAL (Once Serviced): Ours Not Useable. UPGRADED: Excellent. 110w.
FC, DIFF. This one we've known of if never found a nice one to buy. Great to get one to try & certainly a great amp to know. Here we get a Customer's amp & good to hear they got a bargain with it & a high grade one too. A USA advert prices it as $700 about £450, if once imported likely a £700 item. Advert with the tagline "The Finest Stereo Receiver The World Has Known". Will we agree with that once rebuilt? The SX-1010 is a 1974 one, in difficult years for Hifi in the UK, Strikes, Power Cuts & the cruel way 'Comet' heavily discounted good hifi. This arractive SX-1010 is the same size as the SX-838 with the neat row of buttons into the fascia line, the SX-1010 has extra controls for Tone & a 4ch & Dolby Adapter, in this era Dolby FM Stereo was talked of but UK never got it. Impressive looking amp & far better with the Real Wood lid like our 1969 Pioneer SX-2500 has, the SX-838 vinyl wrap cheapened the look. Lid off the top half has 18000µf 63v main capacitors which is very advanced for 1974. The upright power amps are towards the SX-850/950 style with 3 metal cases over the Tuner parts & Phono, showing this was clearly designed pre the heavier Cost-Cutting era. Appears in the 1975 HFYB if no price shown, we do remember seeing it get heavily discounted by 1977 in Comet, but that's the nature of old models once newer ones are out. Huge Transformer looks the size of the potted one in the 100w Sony TA-3200F. SX-1010 rated 100w 20Hz-20kHz if 110w at 1kHz which is the rating that matters to us, for upgrading. 22kg amp when the SX-838 was still 16kg feeling a bit light for the size. Big heatsinks take up the full width, they really spent on this when the SX-838 is on one smaller heatsink. To see where the SX-850-SX-950 got the design ideas from, if much cost cut making them seem oversized tin cans in comparison. Original plug, has a 13A fuse. 640w (640VA) rated so a 5A fuse should be fitted. The Tuner Knob undoes with a smaller Hex-Allen Key. Underneath Woes. This is where the issues of Overheating show, we've seen photos of this to see it's typically blackened, like the SX-838 was. Why the makers didn't deal with Heat issues better on Quality amps is a problem, Yamaha were similar. Not to alter it beyond putting 105°C caps in, to try ideas takes time & overlong wires to avoid. Front controls in the SX-850 style 'boxes' the SX-838 has similarly. The known tricky bit with this amp is the Overheating Power supply, in bright lamp light it's not as bad as others seen online, if it does show it's badly cracked as the dust line on the base inside shows part of the "L" shaped heatsink touches it & as it's all unsupported, it can bounce & break the board. This seems to be the 'Killer' on this amp why they get parted out, it should have been made more rugged. If this board was more smashed, where would you find a good one? This one looks repairable to a good standard & to add extra supporting pieces. Another is the rear AM Antenna is a new fitting type to the metal one as the 1965 SX-600T has as does the SX-838. This is quite fragile & the fitting is very tight, so it'll get broken midway on the flat area if forced. Design. The obvious difference are the large pair of Heatsinks with a total of 8 TO-3 transistors. Doubled Outputs on early amplifiers were more to cover the limits of there only being 50w transistors, if there clearly were 150w-200w ones in the late 1960s. Here the HT is ±54v which is a little low seeing 60v-70v+ on other ones around the 100w range. The 100w Sony TA-3200F runs on ±64v, the 110w rating is counted for Higher Current of the Doubled Outputs. Phono all transistors with a Differential. the board is on top under a can cover, the manual shows it & the 6 fuses board swapped. Tone-Pre aka 'Control Amp' is not a typical design, like the Pioneer SA-9100 it has a "Sub Tone" which adds Shades Of Tone to the Main control. This is like Tone for the more Extreme ends of the Tone, ±10dB at the usual 10kHz & 100Hz, plus a further added ±5dB at 50Hz & 20kHz. How useful this is to be found on speakers. The extra deep Bass needs quality big speakers as many small ones are rolled off under 100Hz for being small. 15dB of Bass & Treble is like some 1960s designs. Means 4 transistors per channel, same board the SX-939 uses if the SX-838 is different as still a FET input like the SX-2500 & SX-828. Power Supply a typical Regulators & Diodes design giving six voltages. Mains transformer from two windings with 6 tappings giving 6 fuses plus 2 more on the Mains side. These multiple fuses seem to be a UK requirement based on the USA-EU versions. To see the fuses intact shows it added confidence, if to get them to fail maybe not so likely to happen. The Manual tells proudly of it's features, this shows Pioneer designs were good but the Comet Curse already had Pioneer heavily cost-cut on lower models. Power Amp with the Doubled Outputs & a Relay. Design still a good one, not too many extra Diodes that became over-used in later amps. What's It Sounding Like? Can't try it yet until that board repair done. Would expect a quality sound & the Doubled Outputs giving a bit more punch. To only really know on first try once Serviced, so until then. The repair got it working, not sounding much as slurry & very aged, if just a glimmer of a good sound. Early Pioneer Design on this 1974 receiver looks familiar from the 1975 Pioneer SA-9500 & a similar Pre-Tone board plus the 1976 Pioneer SX-850 & SX-950. Lots of controls & boards done in a precise way the earlier amps don't quite have. SX-1010 is the same basic outer look like the SX-828 & SX-939 with proper wood veneer. The SX-828 transformer has 'ATT-172' & the SX-1010 has 'ATT-174' so were designed at the same time. Rebuilding This Amp. Shows how aged these Pioneers get, we found they were failing 10 years ago, if can work again. To do several boards not showing a clean sound is unusual in amps, depends how it was stored & used. This Sounded Really Bad until the Power Supply & Main Caps were redone. It was Rough with Uneven Slurry Treble. To wonder how many Rough Aged Pioneers are still being used, if generally the Relay stops it playing. Our Intention was only recently looking at the other Pioneer receivers we've had, the 828, 838, 850 & 950 with a more recent look at a SX-980 here. The SX-1010 being the next one up from the SX-939 & having the same preamp, Power Amps differ if both Doubled Outputs, Phono the same, Power Supply & HT differs. SX-1010 ±54v 110w, SX-939 ±48v 75w. To test with our 'Power Ratings' page ideas. SX-1010 uses 4x 2SC1116A & 4x 2SA747A 100w 10A transistors. Now Done & Run In. Give it an extended Run In as it'd likely been unused in Decades. DC Offset & Bias Adjust the Manual thinks you should do it one way, we ignore that & do it our way. Background not totally silent like later amps, Specs say Noise is "A-Weighted" which is not a true rating, it's not quite -95dB if not far off. Sound overall is of a tight nature if like Pioneer of the 1975-76 era it's not for playing 'Motorhead' & expecting a clean precise sound if few amps can. We've looked closely at the designs & can see it's limits, to experiment on an amp like this perhaps best not tried. Not grainy or gritty, if a 'papery edge' shows on Headphones. Stereo width is good if we've heard better. The Strength in this amp is the Doubled Outputs, Pioneer by this era made for playing Loud & giving a great Slam to the heavy Drum Beat sound. For a 1974 amp, this probably is the Best Receiver available with the design of the era. but compared to earlier amps, it's not one we want to play for Hours as some earlier amps can. It lacks the Smooth Effortless High Treble & Bass isn't as Sweet either. Good Amp to know especially for Wondering about Other Pioneer of the 1972-76 era & this being a good one. On Speakers. No noises in use, good Relay. Speaker connectors are springs which are only allowing thin wire, 110w amp needs bigger cable usually. Sound on TV shows watched just earlier is good, Midrange a little more 'up' than the 1969 Pioneer SX-2500. The Tone Shading extra controls do make a difference, subtle as the Ranges select. Not as Warm or Sweet as some, it's a drier sound that sounds as Punchy as the 72w SX-2500 does, the SX-1010 with Doubled Outputs to get 110w doesn't make a huge difference. The Transformer gets warmer than the Heatsinks, this may improve with More Use as we've noticed this before on long sleeping amps. To test it with our Power Ratings test. Puts out a clean 39v Sinewave at 1kHz, very equal both channels. Puts it around 80w, a true 110w as the Yamaha CR-2020 is puts out 43v. The Doubled Outputs to rate it 110w seems modest. BUY-RAW RATING: Power Supply Board underneath risk of getting overheated, it's potentially fragile as unsupported in the middle. Drops will break it & also the glass fascia. To wonder why a big 22kg amp gets dropped. COOL RATING: 8 good looker with wood case, a large sized receiver. (2023)


1974 Pioneer SX-838 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 55w.
FC, DIFF. The next one on from the SX-828 that we were impressed with. We'd never have tried these 1970s Pioneer after not liking the SX-850-SX-950 ones very much, but the SA-9500 Mk I has got us back into trying Pioneer & this is perhaps the last one to fill the gaps. A huge increase in size compared to the SX-828, this is nearly the size of the SX-850 if 4cm less deep. What a Big Amp for 1974. Shares some construction ideas with the SX-828 but mostly it's more like the SX-950 if less of a tin can despite being lighter, it is certainly a nicer made item. No power amp cage at all which is odd after the SX-828 & the Tuner board is right by the Power amp. Lilac tuner meters if sadly Vinyl Wrap not veneer loses it points on looks for such a big amp. Has metal casing on the pre-tone board, a few tantalums & the switches board is double sided with much ground track. At last those awful Speaker plug blocks are gone, now with bare wire spring connectors. From the progress from 1970 to 1972, this being 1974 betters the 1976 range so is very likely the Best Pioneer Receiver for sound quality, but the (initial) rating of "G-E" on the SX-828 compared to just "G" here suggests not so, as original, if both upgraded well. For the rough Economy of the year, not an easy one to find. Still a hot resistor on the power supply to sort out & some poor soldering there too. The SX-828 is the better amp of the SX-828 & SX-939 to us, the Transistor counts are (828:939) Phono x 3:4, Tone x 3:4, Power Amp x 7:10, the 939 adds a Differential in the Phono, 2 more gain transistors in the tone if no FET & Power amp has Doubled outputs if HT is 44v on the 828 to 45v on the 939 so it'll not play any louder for it's 75w. The SX-939 power amp circuit is remarkably similar to the SA-9500. The first signs of the Pioneer overdesign showing here in the 939 preamp, the 828 has more potential. This has audio qualities the SA-9500 has after much upgrading but looking into the Circuits, there still are quite a lot of deliberate weaknesses & spoilers, not as harsh as the SA-9500 but the sort to weaken the sound quite noticeably still in all ways. Upgrading was well worth it. The Sound of the Amp as unserviced if recently used was quite decent & after servicing to rate it Very Good is possible. But the many limitations in these Amps for us hold the real sound back quite heavily. With an eye to upgrading most amps we get now, we can see good potential, but these later Pioneers need a huge amount doing to make them the sound we demand from amps now. Upgrading was not easy but the results are excellent. This is the Best Sounding Pioneer of all we've tried with upgrades recently, a wide open sound with clean treble & extended bass is what hides in the limited original design. The SA-9100 maybe a more sophisticated sound if it's sound balance was a little wrong. REVISITED: We only had one of these a year ago (2014) & it was one we liked if difficult to deeply upgrade as is typical with the 1974-76 Pioneer. This one is a bit of a mystery. The first one was more used & darkened on the regulator board, but this one is like new. It works fine first try beyond a service so why was it lofted so fast? Odds are it was too big & they bought a "better" music centre as people often did. But 38-40 years left sleeping is often too. It'll clean up to look Mint & we don't even feel it needs recapping (in 2015) before servicing even as so little used. Time will tell. BUY-RAW RATING: Good. Power supply has a hot resistor & bad soldering on our first one. COOL RATING: overall it's 5 good looking amp with black tuner, purposeful if not scary looking but the cheap vinyl wrap case really lets it down on a second to top model, 8 for the fascia as it looks pretty if only 2 for the lid so 5 overall though if you veneered it in American Walnut or Teak it be higher. (2014-15)


1974 Realistic SA-1500 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 35w.
SC, DIFF. Not found any other worthwhile Realistic amplifier to try before, usually they are the 1980s receivers, one as reviewed below. So to find an amp, the bigger 60w one is the SA-2000 & later SA-2001, both seem less findable than the receivers. HFYB lists at £140 in 1979, more expensive than similar Trio. Realistic we only saw the very low power & PA amps by the mid-late 1980s, they only sold the more powerful STA- receivers. These are custom made for Tandy-Radio Shack by the same company Fostex that builds Rotel apparently, so well worth a try. The earlier STA 220 & STA 150 are made by Hitachi. First things noticed the smaller size 386mm wide, 120mm high & 287mm deep inc fixings & then the weight of it. Inside the oversized transformer is good to see, more the size of a 60w amp. TO3 transistors on an internal heatsink. The foil covered card over the preamp a bit cheap but the top lid is real wood veneer & many amps have no shielding. Looks are very like the 1973 Pioneer SA-9100 range & the Realistic brand isn't a cheap budget amp as proved, no ICs in this amp & the service manual findable. 400w is the VA rating which is double what other 35-40w amps state similarly. Impressive array of inputs that you rarely see until later years, 2x Phono, Tuner, 2x Aux & 2x Tape loops one as a DIN also. Speaker outs are less good, either DIN plugs or RCA phonos as outputs. The open grille lets 40 years of dirt through unfortunately so a good clean needed. The build inside & out is impressive though, better than we'd have expected. Design looks unusually good for 1975 also Phono x2 transistors, then a buffer for all input types, Tone x3 inc a buffer, Filters x2 as buffers. Power amp is the typical Differentials then just P-P driver & P-P outputs. One extra as a protection circuit. This a good design, adding buffers usually not seen until 1977 Yamaha amps to stop switch noises & gives a tighter sound for impedance matching better. Overall it seems to be a c1971-73 type design as Semi-Complimentary adding buffers. Pioneer & Sony never did this. From the circuit, sound should be clean & precise if bass is always limited to stop fools complaining. Lots of features on this: Overload light, Filters with 2 options, Tone is Bass, Midrange, Treble & is defeatable. Speakers out 1+2 and 'Quatravox' some sort of mock surround mode. On taking apart the whole long top board covered with the shield is the Phono & Preamp. No Relay, quiet in use on speakers. Does look a bit like Yamaha & Rotel amps in a few ways, if by 1975 many are more standard parts. All cleaned & serviced, to try it, plays music fine for the first time in likely over 30 years. Even aged & unused the sound is very decent, much like the Akai AA8080, no grainy low-spec sound here, sounds much better than the Pioneer SA-9100 or 9500 did on first play. For the overspec transformer & good sound, another unexpected winner here. To be recapped & upgraded, as getting a decent sounding Differential amp is not so usual by the post 1972 era. The amp has an unusually punchy & wide sound for a 35w amp, the sound is well presented if deepest bass is noticeably absent, but this is as designed & has that sort of 'retro' slightly tubby 'ringing' bass that will be real Bass to most until you've heard upgraded amps. Finding worthwhile amps that interest us instead of getting some boring post 1978 amp gets harder as less are to be found the more we get. Finds like this still keep it interesting, upgrading boring 1980s general quality amps has no appeal. Played it for over an hour, the played the 1969 Trio TK-140X all recapped & upgraded. Differences in sound, the Realistic is wider sounding & with the buffers it does seem more precise, deep bass is very different & takes a few minutes to get used to the Trio sound. Back to this one & the sound is preferred, but as we say elsewhere, once used to one amp, others will "not sound as good as they did before". The tubby retro bass is a little unwanted, instead of full deep bass & only by recapping-upgrading will we see how good this really is. On speakers it's interesting, the limited bass is more noticeable if the sound is very decent, plays louder than some amps if not really for use on 15" Tannoys. The Midrange control is a useful one that will solve speaker matching as too midrangey or too dull is the range it shows on use. The clean sine on this is higher than 35w suggests, 28v is more like a 50w amp. The HT is ±39.5v. The 35w rating is underselling this, 35w at 1% distortion 20-20kHz (if no ±dB given) & for the steep bass cut, once upgraded this will be a 50w amp or 50w at 1kHz as other amps rate. The big transformer confirms this. Some unusually advanced circuitry in here, as well as buffers stopping switch noise, the small circuit board tagged on the top board mutes the preamp on turn-off & discharges the main caps to stop noises. Other amps would do this via relay. This amp impressed so much we got a 1974 Realistic receiver on the way. A quick play of this after the 1969 Trio-Kenwood TK140X reveals a very similar sound in this amp, clean & precise. Still not fully recapped but for a supposed 'cheap' amp to sound this good was unexpected. Headphone circuit is not standard & explains why volume needs turning up higher than usual, so we alter that. Now recapped on all except the main caps which at 6000µf are still decent, takes a few minutes to run in & the bass to appear. Then it sounds like... the STA220 with a fresh punchy but tight sound. Sounding much better than the similar Pioneer SA-9100. Realistic early amps are seriously underrated, it may not look much & the lid grade isn't ideal, actually tided up better than expected, but the quality sound is here. A case of Good Amp innards in Budget Grade Build & Case, a bit more care in build quality would make it more worthy. As this has differentials, has to be the most 1960s sounding amp of this design. The sound is clean & detailed, Rock plays convincingly if not quite the grunt of more powerful amps. Not as sophisticated sounding as the STA-220, if look at the difference in sizes. This could take some redesign to better it further, if to be, er... Realistic about the sell price of it. It sounds like a 35w amp, so we'll not oversell it for a higher clean sine rating than usual. Interesting amp to find, we'd not have tried the mighty STA-220 without knowing this. BUY-RAW RATING: Will likely be dirty inside, open grille, but ours was fine beyond dirt. COOL RATING: 6 looks like a smaller version of the Pioneer SA-9100 if budget build quality limits. (2017)


1974 Yamaha CR-200 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 15w.
You're A Little One, Yes You Are. Time to get Cutesy with the Weeniest Yamaha, the CR-200 receiver from around 1974-75. The CR-400 we have here as of typing & it's 445mm wide, 158mm high & 300mm deep in the wood case. The CR-200 has no wood case as he's weeny with a metal wood-effect lid so just 400mm wide, 140mm high & 288mm deep. As on the Jan 2019 blog we saw this had a version of the 1969 Yamaha AA-70 power amp with Capacitor Coupling & no Differential which is likely the only other Yamaha to have this, certainly the only one past 1971. It's still well made as a 1974 amp if it's all on one board with the Transformer & Tuner part at the back. Front still has the 1973 style with the long tuner glass, small paddle knobs, 4 rotary knobs & 3 lever switches plus a Headphone socket. No space for awkward Filters or Filter Amps here which again interested us. Rear panel still Yamaha with no hardboard like some lower models, 2 speaker pairs, Phono & Aux input, Tape In & Out if no DIN socket, 2x AC outlets. 100w aka 100VA rating shows it's not junk also. Inside from left to right is Power Supply with 3300µf main capacitor & 2200µf Speaker Output Capacitors. Two bars on the PCB for support with the Preamp & Power Amp in the middle with Tuner & 2x IC Phono stage TA7122P on the right. 2SC789 x4 for Power Amp Output Drivers are 30w 4A which is decent for the 15w rating. The 1977 HFYB first shows this in the 1977 book as 15w for £100+VAT with a Damping Factor of 40. Tuner 2.5µv sensitivity shows the spec is slightly less compared to more expensive tuners with 1.5-1.7µv. Yamaha tuner boxes have date codes & this has 1975 as '7523' which may be the first year if info is limited. MK plug with browned pins & typical 13A fuse is 30x the rated amp VA wattage. Powers on, the Meter & Tuner pointer lights work showing minimal use, FM works in stereo with a finger on the aerial screw. Aux plays fine & volume on Headphones is Loud at "2" even. Tone is a mix of the Passive type with NFB for the Minus side as does the CR-400 & CR-600. Not thin or grainy at all, it's a very confident sound. Still have the Yamaha CR-400 as original so have a compare. CR-200 is the stripped down version, loses the CR-400 Mic Input & Level plus no filters if adds Balance. No Mono-Stereo mode switch is a pity on the CR-200. The CR-400 is a similar overall sound if more Domestic sounding & a bit of the grainy sound shows that blurs treble. The CR-200 in a Blind Test would be preferred as it sounds cleaner & a bit louder fills the sound out better & was £44 cheaper in 1977. The CR-400 inside has 3 boards & connecting wires, the CR-200 has all on one board with no connecting wires & is tidier inside than the CR-400. Totally different designs. Sound As Original. Punchy fast sound isn't what we'd expect from any 1970s 15w amp but the CR-200 is that & it's quite Bassy too with Wide Stereo, if Bass doesn't go deep it's not Boomy sounding. This is a crazy sound from The Lowest Model, the sound could upgrade more but as Original it just makes the other higher models seem a bit unnecessary. Onto Rock & the CR-200 again surprises as guitar is weighty & trying to criticise is difficult as it even plays 60s Ska well. A Remarkable Weeny amp that sort of puts the bigger Yamaha aside if you are looking for clean sound & not needing more power. After Servicing the next day it still sounds better than it should, quite a lot of ceramics in the design & the sound a little restrained & flat but compared to some amps once Serviced it's design does make it sound more like a 1969-71 amp than the usual 1974 design. Puts out a clean 15v sinewave which is less than the 18v of the CR-400. As with the CR-400 these could upgrade quite a lot to give more Wattage if the 15v would still be the maximum volume & any bigger Bass or Treble sound could get into clipping too soon, so as tempting as it is to upgrade more, to see it's limits are the 15v output. Sounds a lot better than a 15w amp should especially for 1974, it's still limited in sound as the spec is still low for the pricing if it's one to upgrade & see how it does. To Recap & Upgrade. For having all the stages on one board, space is tight & the ceramic capacitors don't have the space to use our usual ones, the reason why these are used despite them having no place in a Hifi amp, if a few Power amp ones could be done, at this level & costing to resell we'll leave them be. The electrolytics have enough space unlike some amps so it should upgrade well. But there is no parts layout & the board isn't numbered, so care needed on recapping. Now Recapped & Upgraded. Interesting sound still if now it's fuller with more authority plus a decent bass. Still with the 'Yamaha' sound as other models so Fast & Punchy with good volume. It's not the last word in Fidelity & could be upgraded more if at 15w it's best not to go further as it's 15w & we can't put a big upgrade into an amp that has a price limit. As upgraded, it is clean & smooth plus has enough grunt to sound convincing on Rock Guitar again this is far from typical even on 40w+ amps. Copes well with 60s Ska sounding clean with no bad face expressions on playing a busy track & to us on headphones it's a good listen as it sounds right. Another great upgraded one from Yamaha, the CR x00 series varies but always pleases. But this is the Only 'Classic Era' Yamaha that uses a 1969 style amp design with capacitor coupling, pity they didn't make earlier amps like this, the CR-500 & CR-700 from 1971 are a bit disappointing. On our Tannoy Speakers. Now ready to sell, see how good 15w is on 95dB speakers. Gives enough volume, Stereo is wide, clean sound. Not big bass or big dynamics but no slouch either. Surprisingly good amp indeed. See a mid 2022 Blog for more on this amp. BUY-RAW RATING: Should work fine after a service. COOL RATING: 7 unusual with the metal lid, if a cute smaller receiver. (2019)


1974 Yamaha CR-400 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 18w.
One of the lower range of the 1973-75 era ones. Appears in the 1975 HFYB for £148 new if the CR-200 also 16w must be a more basic version. 16w at 20Hz-20kHz if 18w at 1kHz, 18w to us once upgraded as most amp limit the extremes of bass & treble. What to expect from a lower model? The CR-1000 to CR-800 show a huge difference in build & sound balance. This CR-400 still has the nice looks, the fascia with the usual levers & switches, no filters, a loudness switch & 2 sets of speakers on 16w seems optimistic. Volume & 'Balance' on one control. Heavy vinyl wrap wood case is high quality still, compared to some feeble lids. The back has the usual Yamaha connectors, there is a DIN version also. No Pre out-Main in pair on this if Phono, Aux one Tape loop & there is a Pre Out only. Multivoltage with AM antenna, AC outlets & "80 watts" as 80VA power capability which is good on a 16w amp. Inside is easy to see it's Yamaha, a bigger preamp board than the CR-800, one board for Power Amp & Power Supply & one for FM-AM tuner. The power amp is the smaller TO-220 size transistors that many amps use & are 40w rated ones. Heatsink is a bent piece of aluminium with a small extra part screwed on, doesn't hide any IC block. Main caps are 3300µf 50v. A modest amp but it certainly looks good value for what we see & hear of it, not the cheapest as the 25w Sony STR-6046 is £120 & the 16w Sony STR-6036 now £76, but Sony ended up in Discount Stores, Yamaha stayed away & kept the quality. See the 1971 STR-6046A review, it was ok but STK amp blocks & lesser build quality & the 1971 STR-6036 was very poor quality. You get what you pay for. First play of it, apparently 'not working' but sounds fine, if needs servicing. Sound is far from what you'd expect, no soft 16w sound here, it sounds lively with a sound nearer to the CR-1000 & it does deep bass well, have we plugged in the headphones to another amp? Not so, it's the CR-400. Simpler design than the CR-800 gives a fresher sound & it certainly has volume. But at 16w it'll be interesting to hear it on speakers, can it drive them? Will be recapped & upgraded, a better mains cable & seeing a 13A fuse in the plug is foolish, 3A is typical & the amp uses a 1A on it's mains fuse. Has to be the best sounding 1970s 16w amp we've heard, the sound is way ahead of others. We can hear it could do with some upgrades, but the basic good sound, based on the CR-1000 sound makes this one a bit of a surprise. The punchy sound reveals the Pre Out would be useful on a 50w power amp as it's not got the small sound the Leak 3200 from 1978 has on using that as a preamp. The User Manual shows the intended buyer for this, one who needs telling all the Warnings that are more typical of today. The comments, based on complaints likely received, assume you barely understand anything as you only had a Radiogram. Odds are most buyers used cheap speakers & never heard how good this amp is on Headphones. The circuit of the amp is minimalist, not unlike some 1960s designs beyond the Differentials & could certainly upgrade well based on the sound, if to keep it within the power. Seeing the circuit it's a surprise it sounds good on headphones, a similar low-bass feature as in the Sansui AU-666 meant it sounded awful on speakers for the lumpy bass. So what's this CR-400 like on our Tannoys as all-original? The CR-400 sounded great on speakers as unserviced & original. A little limited & noisy controls, but if it was the only amp to use, we'd not be upset having to hear it for TV sound. Not bad going considering we watched hours of TV with the CR-1000 just earlier. Looking closer at the amp, it's still well built if the layout of the mains input & outlets so close to the power amp transistors isn't great. Now recapped & serviced, brings the amp to life more. The trouble with amps that have the main caps on the main board is to fit new ones neatly, in this case the amp at 18w wouldn't show much benefit uprating the main caps & making new holes just looks messy, so we left those be as they were good. You could upgrade the amp a lot more, but again at 18w to avoid being too dynamic to get into clipping too early. Puts out a clean 18v sine on the 'scope, 20v is typical for 30w amps if they have more current. Once Recapped-Upgraded. It doesn't sound like a 20w-ish amp at all. The CR-1000 we have & it has a similiar overall fresh balance. Sounds good with a fast sound that is not typical for the power. Bass sounds very decent for the power if not as big as a 70w amp else it'd distort if it does sound more like the CR-1000 upgraded than the softer sounding CR-800 from the same range. It certainly is better than any other under 20w amp past the 1960s. BUY-RAW RATING: Beyond needing a service, Good. COOL RATING: 7. Minimalist Classy Yamaha looks if still far better looks than 20w amps of the era. (2017)


1975 Goodmans Module 90 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 30w.
FC, DIFF. Early ones look Glam Rock cheesy-awful with white controls but still a surprisingly good sound for a budget buy & less need to recap this than the 80. A much better sound here than the looks suggest. But it is basic but the money was spent making it sound good. Later ones had tamer black buttons. But it's still all DIN connectors. The 110 & other higher number model we've not tried yet & they are later too. As with the Module 80, these don't make much money but do sound good for the trying. Not one we'd choose to fully upgrade as it'd outprice it. We found the pictures set we had when selling this. It looks very TV-grade compared to the Module 80 & the looks & build of it are truly hideous with the white buttons. spec looks better explaining why it sounded pretty decent, but the thing has no class lookswise. BUY-RAW RATING: Good beyond stiff sliders. COOL RATING: 2 to 3 the one with the white buttons looks truly awful if would appeal to a Teen Glam fan of the era, later with more sober black buttons but still only a 3. (2012)


1975 Luxman L-100 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Very Good-Excellent. 110w.
FC, 2x DIFF. Beware of buying a messed with one. Requires deep servicing to get the luxury sound with a calm refined quality & at a price. Beats a Sugden amp in similar mannered territory, as in it's not as fresh & lively as simpler designs so down a peg in ratings. But having looked at the circuits more recently than 2012, we can see upgrades to give it the lively sound it never had, what was there was clean & accurate, but the weak master volume was hiding the amp's quality rather heavily, just as the 1978 Luxman R-1040 receiver did. Not really an amp to party with despite the watts. Before servicing it was a very soft feeble sound which was surprising, after servicing it sounded lively but fine detail seemed oversmoothed from the inadequate volume though the bass was lively. We recapped our one fully & found it was just not as wide & open sounding as others for the gain issue if it had refinement in design elsewhere ahead of anything of the 1970s. Awkward 22-step volume control with no solid zero stop may cause problems, even after servicing it & making the zero stop more obvious it still felt unsure, perhaps this one needed a volume control replaced? The relays are important but hard to find if messed with as ours was. One amp we got just to see what is was all about & never really used it much for our reasons as noted, it just didn't stir the soul. It is a memorable amp for how heavy & stylish it is, but sound wasn't so hot which is the point of hifi. An amp that often has got fiddled with & the MTA56 connectors taken away & soldered which is bad. 3 old style relays may be risky too. The case is too thin wood for a heavy amp like this & with the odd collar piece it's a bit awkward. The phono stage sounded poor too. But this amp we had to get 2 missing relays & redo the MTA connectors as it was fiddled with. To us based on this high model, Luxman are a bit overrated & therefore very overpriced based on this amp, this one makes a good price & was high new at £680+VAT in 1979, but many lesser models get offered way too high, like Marantz do too, but we don't see sales unless realistically priced. On getting the R-1040 receiver later, the same sort of sound deal there too, but it was found to be weak on master volume gain unlike how loud other amps of similar power could go. What holds the L-100 back will be similar as the R-1040 as original needs volume past midway & still doesn't go loud enough. This is one of those 2012-rated amps that we may question our rating. The quality of it was apparent as the rating shows, but it was a fussy design & having tried the R-1040 receiver since & finding we weren't too keen on certain aspects, Luxman is a bit of an unfinished story. There are many Luxman valve amps & other transitor amps we've looked at on the 'Other Amps' page. 2023 Update. Not had one since 2012, the huge main capacitors may be past their best & hard to replace for the size. But the Overall sound of this was remembered: a Bouncy Bass Sound that really isn't in Hifi much. Never mentioned that before if remembered. 2023 awareness of circuits way ahead now from Upgrades just to see how far we can go. Above shows Gain was a main problem, the Phono was very off RIAA meaning it could have been faulty, despite the 'Phono Tilt' feature. Luxman in all we've had have Had Quality if always a bit too hidden, the amount the 1979 LX33 valve amp needed. All old amps are remembered & circuits checked over. BUY-RAW RATING: Good if needs good servicing & beware the volume control or bad repairs. COOL RATING: 7 slightly awkward attempt at classy style, the lever switches look strange & rosewood used on amp cases always looks cheap despite it being a premium veneer, it looks too try-hard on a thin case. (2012-2023)


1975 NAD 160 'a' receiver ↑
AS-ORIGINAL (Once Serviced): Recommended/Very Good. UPGRADED: Excellent. 45w.
SC, DIFF. The slightly updated 160a usually has a Bass limiting Low Pass circuit between the Pre & Power amps on the underside & the Power Supply still runs hot, if not all models as stated just below. Based on hearing how awful a similar circuit made the 1970 Sansui AU-666, odds are this will sound awful on speakers too, for the lumpy thick false bass. But maybe not all had the limiting, it's a pair of tag boards with small capacitors on underneath. Still Semi Complimentary too. Just for the Bass limiter, we'd rate it just less than the 1st version as all original with the bass limit circuit, but upgraded it can be as both are so similar, read more in the NAD 160 section above. NAD 160 has an FM Muting push button, NAD 160a uses the same as Loudness instead, a few minor differences inside too. UPDATE: We got one in 2016 with a 43xx serial that doesn't have the Bass cut circuit underneath. The 160 we had before as on the 'Solds' section is a 39xx serial. This 160a has larger value main caps, 13000µf 63v compared to 8000µf 50v, has to be the early run version before the lousy Bass cut circuit was fitted as it's untouched inside where it would be. BUY-RAW RATING: Beware failing overheated power supplies, else beyond that it's a good amp. COOL RATING: 8 as with the earlier version, cute looking amp like the 1971 Yamahas with nice reeded control knobs & a wood veneer lid. (2013-16)


1975-76 Pioneer SX-850 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: (Good potential). 65w.
FC, DIFF. **Updated** We had thought these were Cheap & Nasty things for a long time after having 4 of them, they always sounded Rough way too soon & quickly ran out of power which for their rating was pathetic. But Pioneer are seriously underselling themselves as we've found out upgrading the SX-838 & SA-9500 as the design once upgraded is very high quality. These two suffer from weak sound too, but our upgrades are getting serious now not allowing anything weak in these Pioneers. And does it pay off. Heavily cost cut is what these amps are & it looks on the surface that Pioneer were mass market price-cut efforts out for big sales, being priced £100-150 less than similar powered Yamaha & Marantz. It is very clear the 850 & 950 have a huge scope to upgrade. They sound very rough as the design is very limited with many spoilers & a severe lack of deep bass, so really as-is only deserve a 'Recommended' but upgraded right they do 'Excellent' not that we've had the 850-950 to upgrade yet so won't add this here yet. The power amp is similar to the SX-939 & SA-9500 so shows much potential as the 838 & 9500. The 1980 range including SX-980 are very different with ICs & even more cost cutting. The SX-850 & SX-950 have real wood trim & veneer, the SX-750 is vinyl wrap. We've not had an 850 or 950 since 2012, but have tried many other Pioneer. the trouble is they need so much low spec upgrading they take a huge amount of work, but as the SA-9500 proves, it can rate highly. the SA-9500 power amp board is actually very similar to the 850/950 one so with a huge amount of upgrading, they could do very well, but we'll leave them be for the while. BUY-RAW RATING: Good. COOL RATING: 6 oversized tin can with too much bling & cheesy looking wood veneer & trim to appeal to Ford Capri drivers, garish looks but there are many who like this look & it was the look for most hifi until 1980. (2012)


1975-76 Pioneer SX-950 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: (Good potential). 85w.
FC, DIFF, DT. **Updated** We had thought these were Cheap & Nasty things for a long time after having 4 of them, they always sounded Rough way too soon & quickly ran out of power which for their rating was pathetic. But Pioneer are seriously underselling themselves as we've found out upgrading the SX-838 & SA-9500 as the design once upgraded is very high quality. These two suffer from weak sound too, but our upgrades are getting serious now not allowing anything weak in these Pioneers. And does it pay off. Heavily cost cut is what these amps are & it looks on the surface that Pioneer were mass market price-cut efforts out for big sales, being priced £100-150 less than similar powered Yamaha & Marantz. It is very clear the 850 & 950 have a huge scope to upgrade. They sound very rough as the design is very limited with many spoilers & a severe lack of deep bass, so really as-is only deserve a 'Recommended' but upgraded right they do 'Excellent' not that we've had the 850-950 to upgrade yet so won't add this here yet. The power amp is similar to the SX-939 & SA-9500 so shows much potential as the 838 & 9500. The 1980 range including SX-980 are very different with ICs & even more cost cutting. The SX-850 & SX-950 have real wood trim & veneer, the SX-750 is vinyl wrap. We've not had an 850 or 950 since 2012, but have tried many other Pioneer. the trouble is they need so much low spec upgrading they take a huge amount of work, but as the SA-9500 proves, it can rate highly. the SA-9500 power amp board is actually very similar to the 850/950 one so with a huge amount of upgrading, they could do very well, but we'll leave them be for the while. BUY-RAW RATING: Good. COOL RATING: 6 oversized tin can with too much bling & cheesy looking wood veneer & trim to appeal to Ford Capri drivers, garish looks but there are many who like this look & it was the look for most hifi until 1980. (2012)


1975 Pioneer SA-9500 Mk I amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Excellent. 80w.
FC, DIFF, DT. From August 1975 says a sales brochure. Our pages were missing one of these big SA-9000 Pioneers, so we got one at last. The original amp once serviced has not much bass surprisingly & gets rough sounding too early, as the low spec & many spoilers catches it out explaining the medium rating as original. It's a way better built amp than the SX-950 type & is in a very different league to those mass market receivers. From looking at the circuits, we see the SA-9500 as the pick of the bunch with SA-9500II being a different later design, SA-9900 the 110w one in the 1976 range getting into overdesign & the SA-9800 being later but ridiculously having 23 transistors in the power amp, the 9500 has only 10. The SA-9800 is an awful design yet it sells for £k prices as people don't understand excessive circuitry sounds bad if the 0.005% THD is pointless as it's only for excessive design & heavy NFB. In 2020 one said we didn't like the SA-9800, we've tried the Marantz 2385 with similar huge amount of transistors, the 2385 sounded nice but for 185w was still quite tame sounding. 0.005% THD is of no use as the sound will be limited for Specs wars. The overdesign is obvious here. To get a better sound will be quite a job. The SA-9500 with 0.1% THD actually sounds fresher like a much earlier amp, very low 30 damping factor & minimalist power amp circuit beyond how dog rough it sounds until serviced & adjusted. This amp was plentiful on ebay, a real sleeper dismissed with the rest, but that can upgrade into something excellent, but it's stuffed full of 'spoilers' & low spec hiding what is an amp of high quality to stand with the Yamaha amps even. Only when upgraded do you get a kicking bassline as well as a very clean neutral sound like the best pre 1972 amps, but it's only for upgraders to reveal. It's the second-top biggest difference original to upgraded amp we've had. For the sound of it serviced but original it is hard to be fair to go higher than we've put, it isn't anything special. The Mk II version quickly introduced in Nov 1976 is a very different basic metal box design with less quality in design if dual mono power supplies. Our opinion is this amplifier only once upgraded has the potential to be one of the best amps post 1972, if the original version with a huge amount of extraneous rubbish circuitry to hide the quality is actually pretty average, the hugest difference Original vs. Upgraded we've found. But to upgrade is a huge job as we found out & still there are other amps that sound fresher post 1972 such as the Yamaha & Luxman. Others are naming the 9500-9800-9900 Pioneer amps as "The Best Ever", based on limited knowledge & lazy ideas of long ago. Clearly we are the only ones to know the truth by deep investigating to upgrade & see how hugely cost-cut & dumbed-down these Pioneer are, the ones 1973 onwards are a swine to upgrade. The 9500 Mk I is a Very Good amp to upgrade, but ultimately the switch board is the limiter. Upgraded the 9500 Mk I was decent but as original & unserviced, it was truly awful, and on both we had resulting in the switches making noises on use which needed care. REVISITED 2017: We get another of these to upgrade for a customer, this one is a bit different, a 220v model with 'kettle plug' socket like Sony used. 220v to use on 240v means the voltages inside will run a little higher, how reliable that is depends on spec & tolerance. Customer reports it cuts out which these often do as they needs servicing & a recap. The 'Tone' lever switch always makes a slight noise as it switches between 2 stages. This one isn't much used & doesn't sound as rough as the earlier two were, these amps do age badly if used heavily. Bass is still limited & it's a little soft sounding. The stepped volume control is useless, to put a rotary one is far better to use. The Phono stage is Phono 1 fixed gain, or Phono 2 which only allows gain cut if adds impedance alteration. The Phono is clean sounding & compared to similar it's a decent one. BUY-RAW RATING: Good, but unserviced it sounds absolutely awful if well used. COOL RATING: 7 a big chunky amp with odd side connectors, ahead of it's time if too stark for the domestic scene unless it has the rare wood case to tame. (2014-2017)


1975 Sony TA-3650 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 60w.
FET & DIFF preamp, FC, DIFF. Actually didn't expect this to be much good after the decline of Sony in the 1973-74 era, but this plain looking amp actually sounds very decent. Big ALPS volume control like Luxman is unusual here. Accurate, punchy & clean if not much on the Bass, but considering the TA-1150 only got average rated this was an unexpected improvement. Part of the V-FET series of 1975, this has no V-FETs & is better for it. After researching the Receivers, we've decided this 60w amp is the best one to try. Beyond a few nice touches it is still budget in the casework that leaves it looking a bit cheap compared to the earlier ones & the power supply is a bit pathetic just a board perched on top of a double capacitor. One we'd try again as the first one was a water damaged unreliable thing we broke up for parts as it'd never be good to sell, the perils of mean ebay sellers... BUY-RAW RATING: Good. COOL RATING: 5 budget looks of no real style at all, just another silver amp. (2013)


1975 Teleton TFS-70 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Very Good. 33w.
An amp that caught our eye for it's very 1977 kooky looks, if a 1975 design. By 1977 it was sold under the "Masti" (Matsi?) brand as HFN/RR adverts show, odd rename. It has a very decent sound for what it is. Sadly construction & soldering are very low Clock Radio quality & ultimately it will just end up being a failure which is a pity, unless yours is high grade perhaps. 33w of power with Elna capacitors, no ICs in the audio stages & proper TO3 output transistors. But it forever making bad noises even after recapping & more got us tired of it despite the odd looks & then finding proper quality in the Sony STR-6850. Looking at the 1975 Teleton catalog it's the best looker by far in their way with the plastic silver outer case & horizontal sliders. All DIN sockets & German wording means few made it to the UK if it's in the 1977 HFYB. The volume control loudness step from 4 to 5 is awful. It was worth a try but generally disappointing. Other seen online look neglected & despite the good sounds only one to buy in high working grade to get the ratings. BUY-RAW RATING: Very cheap construction & messy soldering will limit your success here. COOL RATING: 7 has a 1970s Space Age retro silver painted plastic appeal which is why we got one, but needs to be in high grade else it looks a bit sad. (2014)


1975 Yamaha CA-800II amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 55w + 10w Class A.
FC, DIFF. This is the II version of their first Silver range with alterations in the tonal balance, but not all markets got the II versions so they are scarce. The power amp is full complimentary & a 'Tone Jump' direct switch. After doing every upgrade trick the CR-1000 got to the CA-800II reveals the 800II as a slightly warmer sound if better suited to most users who might find the CR-1000 a bit overwhelming. If the 800II is this good, the CA-1000II uses the same phono as the later versions of CR-1000 & actually is a superior sound. One recapped & upgrade by us revealed Class A made no difference at all. Has high upgrade potential & we'd rate the CA-1000II similarly. Typical Yamaha too-hot power supply on this amp is an issue. BUY-RAW RATING: Good if overheated power supply transistors are risky. COOL RATING: 8 classy looking minimalist pro looks, well laid out, certainly a male appeal amp if too stark looking for all domestic use. (2014)


1976 B+O Beomaster 1900 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 30w.
FC, DIFF, Darlington outputs. Stylish & futuristic, sound is as good as the 4400 but an amp that is hard to buy a good one as they aged bad, unfindable sliders fail, visuals wear out so we'll rate it down a bit. For us to get one of these again won't happen as sliders go bad, those dark red caps go bad, too high risk. A real bastard to open & try to service especially for soldering, you end up with one large floppy board with all the components on. No real difference in version -2 or the 2400 remote control version. One we'd run a mile from trying again as it's poorly made & there is too much to go wrong with these. An interesting amp, but having had 3 of these to make 2 good ones from, it shows they aren't made to last. ANOTHER LOOK in 2017: Seeing this first advertised in the Oct 1976 HFN/RR the technology here is a Real First with the touch buttons that rely on you grounding the transistor the pad connects to to create a tiny bias voltage. The trouble was the Volume Control didn't have enough steps especially at low level when too quiet-too loud even in daytime levels could be annoying. The construction of the outside case is fine, but the insides are done too cheaply, the one large floppy board & difficulty in working. The bad capacitors & limited space plus the bulb often burnt out the sliders plastic window that showed the level. The sliders themselves were feeble & of a sort you can't replasce so as said above if you want one, buy 2 or 3 & cobble together the bits to get a working one. Sound was decent, but the money was spent on the casework & touch buttons. Deserves to be in a Museum as First Of A Kind, but to find one & use it daily for the weaknesses is not a good idea. Even recapped the risk of the sliders breaking or wearing out is the problem here. BUY-RAW RATING: High risk of parts noted failing & poor capacitors. COOL RATING: 7 very stylish on first look but a bit cheaply made & not Very Good in use. (2012)


1976 JVC JR-S 600 Receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. Mk I 110w Mk II 120w.
FC, DIFF. The previous latest JVC we had was the 1973 VR-5521L 22w receiver, still staying close to the earlier design quality. This JR-S600 is the top model of the range if we did consider a lower model until seeing the amp had the Tuner wheel missing, so did consider it interesting to buy one. This Large Receiver comes in two versions Mk I is 110w & Mk II is 120w, main differences will likely be Tuner related. We have the Mk II version here to upgrade. It's a large item 560mm wide, 405mm deep & 167mm high at 19.2kg puts it into 'Monster Receiver' territory if usually that's 150w+ ones as the Yamaha CR-2020 isn't considered a Monster at 110w. This is the Biggest JVC Receiver of the era is an interesting one. Plastic side panels with a metal lid & metal chassis, if looking rather Cool & Futuristic. 1979 HFYB lists it if no prices shown, if an online ad found says around $750 which was £380 at the time if UK adds 15% VAT so £440 which compares to other big names at the time. Very 1970s Retro looking, unique design with wide double meters for Tuner & Power Output, the Tuner scale underneath with about 2/3 covered with a perspex sheet held on with 4 screws. The other fascia part has the Tuning wheel, a slow job to run the scale, 25 'wipes' to get it the whole way. Gold coloured section with Volume & Balance horizontal sliders & below the SEA Graphic EQ much like the 1967 JVC 5040 type receiver. This is different to the early ones which had one transistor per channel, this now has one per slider too, so 10 transistors with CR circuits instead of the Inductor type early design. Far from the 1980-s Graphic EQ stuffed with ICs, this is still worthy. The SEA response as the back panel shows is different to a standard Tone, to get +12dB gain at 15kHz only gives +6dB at 8kHz etc so similar on 5kHz the full +12dB gain but at about 2.5kHz only the +6dB gain which we found doesn't quite suit as well as a Tone stage will. Top lid off with 3 top edge screws & 2 each side on the lower edge & the lid comes off with the plastic side panels. Metal is a little thin for the near 20kg weight. Multivoltage block under the fuses stage rear left corner. Inside is like the 1967 JVC, it's chaotic & looks a bit of a job to take apart, if few aren't. Large round transformer case if it's a single power supply, the label on top shows it's a toroidal type. The TAC 47 power supply board fitted on the end of the big caps is a difficult one, the ±46v supply is from here. Large Power Amplifier boards have extra sections, one for the Relay-Protection & the other appears to be a Tuner Power Supply. Tuner is on two layers midway & the Front panel is mostly the very long line of ;switches if the right side has the Phono & SEA section which will be a tough one to get to. A chaotic amp for sure, if it looks good now it probably looked very dated by the early 1980s & only Retro gets it cool again. Rear panel has 2x Phono, 1x Aux, 2x Tape Pre Out-Main in & 2x Speaker connectors, push button bare wire types. Surprisingly for 120w the Mk II only says "300w" which is 300VA max power. Phono is 2x FETS & 5 transistors, Aux goes direct to Switches & Filter Amp x2 transistors, The SEA is 5 transistors per channel, Power Amp has 2 Differential pairs if otherwise a straightforward design with Doubled-Parallel Outputs. NFB is very low on this Power amp which needs good design not to sound awful, the Power supply seems a bit lacking, but to try it out. JVC amps as the 1966-73 ones we've had do sound good, always the quirky build quality, if this into 1976-78 is more into their Mainstream era with the boxy silver amps, as the typist's Uncle had at the time. Power on, cool Blue meters & rounded lights on the panel all work, getting bulbs for those would be a job, they share the same power supply so Power on, Aux & then push Spk-1 the lights go dimmer. SEA REC appears to add the SEA to the Tape Outs as no different in listening. Sound as Unserviced & Original has crisp treble, the weight of the Parallel outputs is noticeable, if it does show that cardboardy crispy sound that is often the 1980s sound. Stereo width is average. It plays Rock with the idea the sound is good, but lacks the grunt & believabilty of some amps. The day before we played Max Wall 'Dream Tobacco' & this (upgraded) amp really involved you in the sound, here the JVC plays it, if lacking the will to keep you listening, we don't play it for long. But we've played lots of upgraded amps to listen 'from above' to pick up on what is lacking elsewhere if overall the JVC as a 1978 amp is more lively than the Yamaha or Pioneer of the era. The Design. Phono has 2 inputs & the circuit shows they are amplified separately if the specs show MM 2.5mV level. Aux goes to Volume via Switching, Balance & Loudness. Preamp after Volume has 2 gain Transistors & the Filters are passive with minor circuit limiting & some NFB. The SEA-Graphic EQ block is amid the Preamp & is bypassable as the 1967 designs if still the Preamp isn't bypassable as it adds gain. SEA circuit has 5 transistors, these are Buffers per stage that have the Frequency limited stages, no Inductors in the 1976 SEA. Signal to Pre Out-Main In sockets & onto the Power Amp with typical Differentials, an adjust pot on the Diff for AC balance. Doubled Parallel Outputs for the 120w. 71v 22000µf main capacitors with 60.3v. The amp itself is pleasing, a bit tricky to work on if the Power Amp boards unplug. The difficulty is the 2 large main caps have the Power Supply Regulators board for the Phono Stage & Bulbs is soldered on the end, read the Forums to see who broke theirs by not doing it right, if it's not hard to unsolder. The Sony TA-3650 amplifier from 1975 does similar, but for the size of the amp, it's a cheap-out. The front left inside board with big resistors & the Relay is a 'Power Switch Protection Board' much like the Marantz 2385 Soft Start board. Phono board is the right one with long plug blocks on top of the Tuner. The SEA board is on the back of the sliders & the 600-numbered board below it is the Preamp. Strange use of Power Amp boards, the L one has the L Power amp plus part of the Power Supply for Tuner if nothing to do with the Power Amp. The R Power Amp board has the Protection & Relay circuit. A chaotic design with the Relay board having an extra space for a 4ch amp most likely & the Fuses-Multivoltage lump just tacked on the side. Very bizarre design if JVC always were, look at the 1967 ones. The Brown Glue on some caps is a mess & dried out if can be tided easy enough. Upgrading. To do the Power Amp Boards with their additional sections first. This brings quite an improvement to the sound from the as-arrived sound we didn't think much of. More to do, but the Amp is now a lot more interesting to play. As Serviced & Upgraded. Not Run it in yet or Adjusted if runs cool. The Volume Slider on the top edge needs care not to knock it & turn on at Max volume, one to watch bewfore turning on. It sounds decent, tidy if not overly exciting. +1 on the SEA 40Hz & 15kHz livens it up better. Rock cranked up a bit Louder sounds solid as a low NFB amp will if the real gutsy weight isn't quite there. Clean but Dynamics a little restrained. The Jam "Start" is a test track we use often as it has a huge slam & the JVC does well with that. The sound punches but loses some focus if copes better than the Rotel RX-1603 did. Very Silent background on this amp suggests a little tamed to get the S:N ratios low, the Manual only shows Damping Factor is 50 if HFE states Line as -95dB noise. To Run It In next & test again, who knows how much use amps have had in recent years. Worthy of an Excellent so far, for the 1976 amp as 1978 Mk II version it's certainly a worthy amp. Now Adjusted & Run In, the sound is clear & precise if still a litle restrained in crispness if comes alive better past "2" on the Volume. If this was ours, we'd consider upgrading further, but previous Relay amps get difficult to avoid Relay difficulties & not for experimenting on a Customer's amp. Sound is a little on the dry side so to see what else it can do as it's otherwise a good sounding amp. Not really much else to do, the Power amp design is a little restrained & the low Global NFB is tricky to get the more Rich Bass sound from as we've found with other amps, often it's tamed to lose the edgy sound. Looking at the back panel, it says "300w", 300VA max mains Power draw, which for a 120w amp is quite lowm the 110w Yamaha CR-2020 says "690w" which is typical for a Multivoltage Amp. So to Try On Speakers as Headphones doesn't always tell the full picture. SEA Tone isn't the same as a regular Tone, so a little playing with to get your sound. The Amp matches 1967 Tannoys fine, an upfront if not mismatched peaky sound, the SEA gives a good range of variance. The Sound is a very tight one if the Parallel Outputs give Bass a pleasing extra to what didn't sound so lively on Headphones. Stereo width is good & the sound is very clean. The Tight Sound can veer towards dry as some male voices on TV sound were a bit flat & the SEA doesn't really have enough sliders to match our usual sound which we found with the 1967 JVC Nivico 5040 & others. It could do with one at about 8kHz which is left a little lacking as the graph on the rear shows. The 40Hz one for Bass by itself suits, to not need the 250Hz one if again a 100Hz slider may suit smaller speakers better, 250Hz is a bit 'thick' sounding if used with gain. A sound sounding more 1980s Tight than the more Open late 1960s JVCs sound, if the JR-S600 is precise enough to perhaps suit later speakers even better. Interesting amp to know & to wonder if any 1980s JVC may appeal. BUY-RAW RATING: Needs good Servicing to awaken from the soft aged sound if otherwise a good amp with no problems. Outer Case metal is a bit thin for the weight, watch the Power Inputs board, ours needed repair on an old repair. COOL RATING: 7 nice retro looks bordering on the Crazy as is the inside build, but we like it. (2018)


1976 Marantz 2385 Monster Receiver ↑
AS-ORIGINAL (As Unserviced): Disappointing. SERVICED (estimate) Recommended-Very Good. SERVICED & UPGRADED: Excellent 185w.
FC, DIFF, Triple Parallel Outputs. **Quick Opinion: These Amps are very highly priced aka overpriced, they don't sell. As original, aged & unserviced they sound slow & muddy, they don't sound good at all explaining why ours had 4 owners in 9 months. But Serviced they Improve a lot, if a huge job to do & then Upgraded they sound even better. Once done right you'll not hear much better, the ICs only limit Tone Gain when played louder, but the tired aged amp won't please. Review: For our 175th Amplifier Review, we get a Marantz 2385 huge 26kg 185w Receiver. We've wondered about these Monster receivers since being frustrated by the Sansui G8700DB that we only got to Service if not Recap-Upgrade. Our 174th amp was the Marantz 4070 so it was a hint on which to try next. We've blogged about Monster Receivers before & will Blog further about this on The Blog to not have this section be too long, if relating directly to this amp. For the huge size & weight of this amp, after 42 years they are going to be aged, dirty inside through the metal top lid grille & the risk of bad ld rep[airs is your gamble. Ours got an aged one but from taking it apart to get to the preamp stages, it looks untouched & the output transistors as well as the Power amp board look untouched. First repair we done was the rear mains Fuse as this type seize & break on trying to open, we had an exact same one with a 30mm fuse, if this is a UK model with the 20mm fuse, it'll do. Sound Quality as Original & Unserviced. Opinion on All-Original & Unserviced. Interestingly the same sort of sound as the Pioneer SX-1980 we heard in 2002, it has a rich weighty sound, treble lacking with slight grain, deep bass lacking & a lack of depth & not much Stereo width. Not 'Audiophile' sound at all & 'High End' means little. It sounds slow, tubby & after a while the rather flat soundstage got a bit tiring, if we can hear it would service, recap & upgrade well. This is playing with Tone set to Off, with Tone switched On the quality noticeably lessens, as the Tone is a poor design & led to the false marketing idea that 'Source Direct' was better when the Tone is made with sodding ICs. But read on... The Design. HT is ±75v with Two Transformers in the large can with Double Main Capacitors of 6800µf each, which isn't so high. We know this has Tripled Parallel Outputs, we know Doubled Ones sound good to give more weight to the sound. The minus to this amp as we knew from the circuits before getting, is despite the size the Preamp-Tone disappointingly has 4 ICs the common TA7136P, instead of using 2 transistors instead per IC, we get some overdesigned Class B push-pull junk plus a stack of grainy Ceramics all over the Tone. IC & Ceramics to us is budget price, not Top of the Range £977 when New gear. Fascia off, front off leaving the board tied upright & boards all loose isn't Service Friendly, you can see why no-one bothers service these. Lots of boards & cable plug ins with the risky wire wrap that breaks away easily. As this is a 1976 amp, risk of smokers nicotine inside is our issue if the grease from nicotine helps stop corrosion, maybe it's not so bad but lots to clean. Double Relays inside, plus a Power supply in true 1970s style that gets very hot, one resistor we read 120°C on & it has several capacitors nearby. all the Main boards do unplug, one has a wire to unsolder if to label all is important else you'll have no idea as one board for Selector-Mode has a remarkable 11 plugs all of the same size. All those aged connections to service too. For the type of wrap wiring used, be sure you'll find a loose one or more, so care needed. This amp is insane & be sure some have tried to service & then realised they didn't note the plugs which fit either way round & got too many loose ones. We tell this to warn of what can happen, it's advanced stuff. Several boards removed, no point in just servicing, best to recap too in one go & be sure the boards are all mucky too so the amp all needs a proper clean & then it looks fresh again. Even if yours was clean inside which is unlikely, a lot to do just to Service this amp properly. The huge heatsink with the Power amp board comes out in one lump so not hard to work on. The NPN x6 on one heatsink & the PNP x6 on the other. The rear fuse seizes & to unscrew on Bakelite cracks it if we had the exact one spare from amp parts. The top lid originally is Black with three rows of grille holes & 3 side screws per side plus ones at the top. The Volume control as noted below is a solid aluminium one & the fascia mid part has a groove over the buttons, beware missing or repro bits on these. Appears the vellum paper yellows with bulb heat so it should be Blue lights, not Green. The 2500 & later 2600 with the different tuner, both have the 'Scope display have noisy fans, plus the glass CRT tube is like an old TV one & these can go low emission. The 'Stereo' light stays on as you’re playing Aux, Phono etc in Stereo, not just to do with the Tuner, set to Mono & off it goes. Some 'unsafe' design is the resistor by the Relays that is visible through the top grille has 240v AC on when on & still 185v AC when off. A paper clip or kid poking around could short it to the case easy enough, it may be Off but it's directly on the Mains. Upgrading & Recapping. Best to Service & Recap in one go, the wraparound wires & many plug blocks are too much to do twice. We're going to do all but the tuner boards, the large left one, the left fllor one & the left small one, plus the huge 6800µf main caps are actually 2 caps in one can & as these will still be good, to leave be if the values today are much higher. Tracing the circuit to see what sections do surprisingly, or maybe as expected, there is quite a bit of dumbing down, even on a 180w amp. Treble is limited & so is Bass explaining why the sound wasn't that appealing on first try. But who will get their 2385 or the bigger 2500-2600 upgraded, sadly the 'Boy Racer' types only love the watts not the quality so here we might be creating an amp that no-one wants as they don't understand it needs bettering. Beware of Board or Circuit errors, CT24 is marked "-" yet that side is the "+" side, oops. Power Supply & Relays. Power Supply is modest for the 180w rating. Very Hot resistor on the board. Fuses are for the Preamp-Tuner Power Supply & interestingly the right of the 3 is for the Bulbs which are DC so good for modernising the 8 hot bulbs to LED bulbs with no flicker like most earlier amps do. Small Relay is for Speakers. big size one like Cars use is the Mains-On one with a Protector circuit. A big resistor in a heat shield is 'R003' on the mains stage, the EU circuit shows no value if the 110v version & Parts List puts 22ohm 10w on it & it appears to limit Mains voltage for some reason. The big relay is a 'Soft Start' probably to stop a huge thump on turn on & the 22ohm resistor on mains to reduce the mains surge on turn on. What Do The Tone ICs Do? A look at the Marantz 2330B circuits shows the IC replaces a Differential pair and a gain transistor with low NFB. The IC instead needs 11 transistors & the Class B push-pull stage instead of the single transistor. To replace the IC with 3 transistors & the circuit would be nice, but the HT is ±, the other boards aren't or are higher voltages & sadly too much would need altering. You can apparently upgrade the TA7136P IC with an adapter board to put another type of IC in. Once Back Together after Recap-Upgrade. Now back together right which is probably the toughest amp for how it comes apart & all the risks of it, it finally pleases us. Thinking the ICs mangled the sound was blamed, but actually past the taming they need as it can pick up Mouse noise of 27MHz, to tame the ICs just enough is the skill. For 185w it's not as much on the Deep weighty bass that we know from other upgrades, if the Power Amp stage we didn't do much yet beyond recap to purposely hear what it'd be like, similar reasons to buy an IC preamp amp & a Monster 185w one. The obvious comparision in power is the recently sold 130w Sansui AUG90X. One test track that tells how much a higher power amp can kick is Marvin Gaye 'Sexual Healing', the first beats are hugely dynamic & the 2385 easily bettered the 90X on that test. Stereo Width is way improved from before. The amp has good Bass weight around the 70-100Hz level but it falls short on the real Deep Bass 30-50Hz which doesn't give enough weight to Rock Guitar. But it does give life to the Acid House era tracks, so perhaps the 2385 is more a Dance amp than Rock. It's not been Biased yet if set much like the marks on the adjust pots show & we're giving it a workout on Headphones heat builds up showing bias isn't adjusted right. We did try the Marantz 4070 as a preamp on the 2385 power amp & the 4070 pre bettered the 2385. The 4070 power amp is upgraded to the same level as the 2385 for these compares & the 4070 2x35w mode was found sweeter if the 2385 sure has the volume. Louder treble tracks do catch the 2385 as a bit harsh, if similar on the 4070 were sweeter. The Sansui AU-G90X amp was an 'Exciting Amp' for the 130w of Bridged Power the design actually is, but it always seemed a touch too dry. The 2385 goes further with the 'Excitement' & is more Musical than the 90X if could take some more finesse still & a proper Deep Bass like no Shop Bought amp will give you. Some of the previous ideas we had on Monster Amps were Spot On: They sound dull aged & thick sounding, because they really need a Service & Recap, they've had 40 years of use unlike many we get that got 2-5 years & stored away. The opinion on the ICs will take more to see how they affect the sound. Playing it Flat the Tone On or Off doesn't affect it at all on playing louder music. the 4 ICs used means quite different to what you'd believe, all 4 ICs are in Circuit always, it's just the Tone controls that get bypassed, there is no Bypassing the entire Tone Stage as it adds Gain. But we've changed the spec of the Tone board which transforms it. The Bassy sound of an Unserviced Monster Amp is mostly as the treble is so dulled down accentuating the bass. But how many buy Monster amps wanting Hifi, they just want the Watts. "Monster Amps" are considered "Not Audiophile" Amps, but based on our unique upgrading, that's not true. How many of these Monster Amps sold? 1977 £977 is about £6000 these days meaning probably a 'handful' sold & the rest were discounted to clear by 1980. Biasing The 2385. DC offset measured on the Speaker Outs with no speaker connected & the two middle pots R729-730 are spot on set midway as original. Bias-Idle Current is too awkward & risky to use the J7xx pins as was soon realised, too cramped so can't get to the right one, so to use the middle two of the 0.68R resistors which have hooks bent into the lower ends is far safer. Either way reads across two resistors so not strictly true bias reading as double circuit. Our L was 38.3mV & R was 42.5mV explaining why it got a bit warm. Manual says 25mV if opinions will vary. Looking For 2385s On Ebay. On UK & USA sites there are surprisingly 5 of these as of Aug 2018. Some are 110v-only versions & at 700w max power best avoided unless you have a suitable step down TX. The problem then is Originality, Repro Fascia part as detailed below plus some seem not to have understood the Volume has hex bolts so did foolish things so the volume has the wrong knob on, not that you'll be told of this. UK one has repro fascia & wrong Volume, German £4650 overpriced one in £400 repro case has repro fascia, USA $2500 one looks original & is multivoltage, $3160 has the wrong volume & is 110v, very nice $2800 one is 110v. Another 110v at $4000 has Gold fascia edges & buttons. Beware Repro Fascia Parts. The huge fascia is the outside frame with the centre raise part with the tuner window, buttons & LEDs as a separate piece. Four Aluminium Hex bolts hold it on as with other Marantz of the era. Note the two side bars to the central part, these are separate pieces too & rear screws hold all these on, as in you can undo the fascia into 4 metal pieces. Repros are the mid part & side bars made as one piece & tellingly lacking the long groove between the row of LEDs & the buttons. The original centre panel is lightly brushed horizontally, the two side bar pieces are brushed if vertically once fitted. Easy to spot Repros now. Check out the original Sales Flyer-Brochure on HFE to see it as original. As you see on 'American Pickers' it takes one knowing the original to spot the repro. Repros are fine if it tidies a damaged one, but not fair to not tell it lacks a major original part. LED Bulbs. The 12v ones aren't bright enough so you need the 8v ones, on ebay. Parts That Get Problems. For the size of the amp, these have usually been used since new, not 2-5 years use then stored away. The fact repro fascia parts are made tells, the Balance control is vulnerable as it sticks out beyond other controls, a drop or hit on the face will break the balance & could break the fascia part & glass. The aerial part at the back also gets used as a handle & ours had the clip part on the wrong way if was fine. The rear fuse seizes with age so easy to break the bakelite parts. The Volume Control needs a small hex wrench to remove explaining why these are missing or damaged. The 4 hex bolts on the fascia show signs of not using a box spanner & the 2 bolts under the knobs are just too awkward too. Then the problems inside with the electronics from damage can be a big problem. Huge thin metal lid gets tatty, original tall feet missing or damaged, correct screws for top & base covers missing. It's like buying a Used 1976 car, it needs a lot to bring it up to standard & amps have no MOTs. A Further Listen after we get another Balance control tells the amp is in the league of the 1971-72 amps for a clean precise sound which with ICs wasn't expected. The Dynamics are Huge, Treble is tidy & detailed. It could be sweetened more & despite 185w with all those Parallel Output Transistors, Lower Bass is not as weighty as it possibly could be, it's a Tight Mid Bass but doesn't give that pleasing Deep Rumbly Bass that we can upgrade other amps to give. See the Aug 2018 blog for 2385 vs 4070 to really tell the sound of this amp as the above isn't the full story on more listening, to get used to the amp & compare it with others tells a lot more about it than one-amp listening sessions. We'll test the Preamp to see how the ICs cope & when they start to clip in relation to the Volume control setting, Volume comes before Tone to not run Tone at 0dB if that'll be on the Blog about ICs in Tone Stages. 2385 on Tannoy 15" Golds. A 185w amp on 50w speakers needs careful use for obvious reasons, to really only use speakers of similar power if with 95dB Tannoys you'll not need to turn it up much which we didn't using it & loud enough around "42" (-42dB) on the volume. Big sound as you'd expect, not heard the speakers like that before with more mid bass sounds really coming alive, it has lower midrange-upper bass weight that may be too rich for some even if the Treble as upgraded is crisp. Big sound with huge dynamics is what it plays even fairly low volume, if again Deep Rumbly Bass is absent. Listening further to TV Shows with familar tunes as tested on with other amps, the 2385 is a loud amp appearing a little flat sounding meaning it lacks the sweetness & sophistication of other amps. This is actually as the amp has no NFB stages & low Global NFB, other amps are more Domestic sounding. UK BBC shows they make don't limit the high treble & we heard this distorting with or without Tone Gain which some amps, if not all, can play cleanly. This needs testing, it may be the BBC sound that distorts as hear wider range? Not heard that treble distortion since, could just be the Broadcast. We used it with -1 on Midrange which made it better for the volume used, not a mismatch just because of the upfront sound. Matched the Tannoys spot on though as the 4070 did. It's not really an amp to use often for TV sound as you'd annoy others, if a large room in a detached house is more it's owner. We'll try to sweeten the sound further. If you need that 185w power in a large room you'll probably never want for any other amp, but only as upgraded which is the tease this amp keeps bringing. See more on the Blog Pages from July 2018 as this section is too long already. BUY-RAW RATING: These huge 26kg amps have been used all their life possibly & will be showing age & old repairs. dirt inside could be bad as the open grille lets it all in. SERVICE & UPGRADE RATING. This is highly advanced to take apart & if serviced right you can still get problems with breaking wires on the wraparound pin plugs, even if you're the first one to take it apart. An amp you'd need to be crazy or very well planned to try to redo after having done ours & be sure it'll need or have repairs. Probably why these sit sounding dull & slow as who would work on them like we did. Would we do another? They certainly deserve bringing to life. COOL RATING: 8 after looking at it for a while, the fascia is typically nice Marantz, the huge footprint of the amp is too big to use without planning for it. It makes amps we thought big look 'funsize'. You can get various Repro Wood cases if then the Cooling is limted if adjusted right unless you crank it up high on inefficient speakers, heat isn't an issue. (2018)


1976 Marantz 2235B receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 35w.
FC, DIFF. This is an update to the 1975 '2235' if beyond the rear mains cable placing & 1 less Tape related socket pair, it seems much the same externally. 35w power here a good seller. For a 1975-76 amp still has those small square speaker springs, here they are nice if they age badly. The Tuner bulb section is often a worry on these later 1970s Marantz, not too much plastic if repair needed. LEDs go well in Marantz so it'll stay as we fix it. We had the later silver tuner panel 2265B below 8 years ago, now the Marantz are aging & getting unreliable. This still has the wood effect lid, the 2265B had a boring plain one, if the styling more towards the 2385 with the bigger speaker connectors. Top inside one cage over the FM front end if the rest on 4 boards. Small power supply front right with a relay if a possible hot resistor right on the bigger capacitors. Main Amp Fully Complimentary with Differential, Driver, Splitter-Bias-Protection, P-P drivers & output drivers. Phono on 3 transistors per channel. Preamp with 4 transistors with the Bass, Mid & Treble Controls on the usual Marantz NFB. Bulbs on AC if the LEDs work well usually. No ICs in this beyond the Tuner will have a fresher sound amp here. Tuner has an IC for the MPX stage only, 6 ceramic filters. Date stamp of '1976 525' says it's a 1976 amp. Underneath the Phono & Preamp-Tone. As typical, the Power amp board is tightly fitted, making Marantz harder to work on. Proper TO3 outputs on this one, in a line of 4 midway on the heatsink, Marantz (2S)A757 & (2S)C897 marked. Inside top has the Power Amp to the right, Power Supply front right is a bit lacking for all the space underneath, three Tuner boards & a small 'Level Set' buffer board on the front left which is Tuner related for Dolby FM that never was used. Underneath has a Fuses board, Phono board part under a screening panel & front with the Preamp Tone. Always a different design on Marantz, only a few in the same range are similar. Well used amp as the top inside lid marks show means it was a liked amp. What's It Sound Like? First try when it arrived, the Power Supply seemed vague so only to try quickly, at least it worked. Basic service & try again. Not useable, yet again a badly aged Marantz. Sound uneven if wakes up but an obvious hum gets it Off fast. Seems the last 10 years has made a lot of Marantz be too far gone, if well worth the rebuild. This is a Pro opinion, it's knackered, shows what people are using still & not realising it could get worse. A M2270 here has got worse & it blows a main fuse, that to be worked on still. How About Now? Some work later, always good to hear it near Original. To see why it got a lot of use, decent sound in here. Far from done, slightly grainy if a crisp clean sound. Bass a little Retro Bass as designed, if on Headphones it sounds Rich. This is a really nice sounding Marantz. Now Done If Not Run In. Trademark Marantz sound obvious. Bass is sounding good on Headphones & not too thick or too thin, the Retro Bass is done well on this one to sound fresh. Treble is decent without Grain. For a 35w receiver from 1976 it's tidy sound beats quite a few. To Run in next. Bulbs All Done. This does look nice with all the Bulbs done. LEDs won't fit right so you get the original type glass bulbs from non UK sellers. Now Run In. More Confident sound now, a bit vague before. The Retro Bass on Headphones sounds a little lumpy if not obtrusive. To try on Speakers as this was made for Midrange Speakers that would suit the Bass sound. On Rock it's needing volume turned up much more near midway on Headphones, for 35w it's not bad though & a tidy sound. A good value popular receiver with a decent sound for it's power. 25v Clean Sine output. Tuner in FM Stereo is decent, crisper than the M2385 one. Phono similarly clean sounding. Speakers to try next after checking adjustments. On Tannoy 15" Golds. Speakers way ahead of a midprice amp is a harsh test, to hear the Retro Bass the customer chose it for, after trying others. The 2235B sounds clean with a clean midrange, but the Retro Bass isn't for these speakers at all. It sounds 'Boxy' with a limited full Bass, using Tone to try to get the best sound leaves it 'wanting' to us. As expected really. The Bass created to make small speakers richer probably suits 6" drivers fine as they'll not play under 50Hz anyway. Our Tannoys play full range including Sub Bass which the 2235B strangles. Horses for Courses. It can be possible to lose the Retro Bass in upgrading, the amp otherwise is capable. Rating As Upgraded. Depends what size speakers you use, match it with Bookshelf speakers it'll be it's best to get 'Excellent', but not for Big speakers with the Retro Bass in place. Retro Bass Updated. The Owner got tired of the Huge 50Hz Bass Boost that Retro Bass adds & sent it back to be Updated. They originally liked the sound on the amp as made as more Bassy than usual, if our upgrades add a proper bass making the retro one excessive. It sounded great when we tried it & on speakers, as good as a Marantz usually is. The 2270 has this awful Retro Bass too, we took it out if asked the customer. BUY-RAW RATING: Marantz getting too aged now. COOL RATING: 8 Classic Marantz looks best in the wood effect lid. (2021-2022)


1976 Technics SU-8080 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 74w plays 55w.
FC, DIFF. A higher quality Technics, the Panasonic 80A with the new trade name, if no 80As exist. Still based on the high quality National-Panasonic as ones above show, this amp is the Top of The Range answer to what Pioneer did with the SA-9100, giving a 'new breed' of sophisticated amplifiers where higher power but still good quality, before brands cheaped out. This has Double Transformers, an idea sometimes used as in the Harman-Kardon HK930 above that doesn't really add much in reality, much like Class A, but gimmicks sell. This you could be mistaken for thinking it's a 1984-86 amp for the Gunmetal Grey finish, LEDs & solid controls, the fascia is aluminium if thin but it feels more solid than the 1984 Sansui below & on taking it off, it's actually a solid cast piece of some weight, quality. Two LEDs on the amp switches & a bulb on the power if styled as an LED. The build of this amp is very pleasing, if the front on two layers wil be fiddly to work on as was the Pioneer. The power amp section has a crazy 11 adjust pots, the 'Technics' can shields 6 transistors, it's not an IC, it's a double FET. Sadly the Tone is a generic 7136P IC which is bypassable, but be sure you'll use Tone if you have it on Speakers especially. The sound on first try of one we got to work on for a customer, after a little servicing, is showing this is a Quality Amp, a precise clean sound, Treble isn't as extended as some & deep Bass appears a bit restricted & lumpy if maybe not awakened from enough use yet, if Stereo width is very good. Using the Tone stage with the IC, the quality loses focus, if it takes a trained ear to hear this & on Speakers it'd barely show, but on Headphones it does. We've played it part Serviced, the sound isn't rough like the Pioneer SA-9100 was. This is a bit of a "Sleeper" amp as are the earlier Nat-Pan ones. For 72w it has a punchy sound & has good upgrade potential as well as being a good looking amp before things got plasticky. We'll compare it to Sansui AU-G90X next, we keep that as a latter-day Reference Amp. The 90X has a very tight precise sound that some may think is Clinical, the Technics isn't far off in Fidelity if has a different 'softer' sound if is a good listen even as original. Looking to upgrade, the speaker sockets are hopeless, it tightens thin bare wire only onto a poke & tighten way that by the chew marks shows it's no good. To refit better 4mm sockets is possible. Phono stage is unfortunately into overdesign with a complex P-P design like Yamaha & others used. The Tone stage is sadly mediocre with a common 7136P IC instead of putting a few transistors. It has a heavy bass filter in the stage & really doesn't want you to enjoy deep bass that a 74w amp craves, as noted by the first play above. Both of these stages are a case of 'see what it sounds like upgraded'. Beyond that, construction is very pleasing all well labelled & nicely spaced, making the Tone IC unforgivable really. On trying after recapping the front stages, the Tone when switched in does noticeably deteriorate the signal, but played flat it's of high quality. For Speakers you'll usually need Tone. The front panel board aren't too well supported inside & putting the fascia back on is fun (tilt the unit upwards). With our upgrades the Bass is much improved, tight & deep. It does sound clean & punchy but does lack a little realism, if the power amp needs doing next. Interestingly for a 72-74w rated amp it only uses 80w rated transistors, but has a 'power limiter' aka soft clip circuit. Seems unusual as higher power transistors are fully complimentary & at this time the specs were only this for matching NPN-PNP pairs. To use as it stands rather than alter seems wisest. For a 1976 amp this is early days of this type of design & will explain other unusual design. An interesting amp, going for a radical new design that Yamaha took note of for their 1977-78 ranges. The power limiting & Tone IC isn't good, it is a compromise, but for what it is, this is a pleasing amp & an important one in the development of Hifi into Fully complimentary design, if perhaps a liitle early. Not like us to say a later amp would be better, but an 80w Technics amp with improvements in parts spec may indeed better this, if the trouble is by 1979 cost cutting ruined the quality. SU-8600 is a 76w one in 1978 or SU-8088K at 85w in 1980. As Technics are National Panasonic, there is the 1967 SA-65 reviewed here. For the power limiting, to consider it a 72w amp won't really give you the right idea. Consider it a 50w amp & the clean sound will certainly please. But compared to a 40w amp like the Akai AA7000 from 1966 as we've just done, "where's the bass?" will be a question. For the 1972-77 era, this is a quality amp with a precise sound, if not as exciting as you'd want it to be. We've recapped & upgraded this with our usual quality parts & it's certainly a high quality sound. Midrange is accurate, treble is punchy if some vagueness is noticeable on busy tracks. But it does sound too mannered, a little restrained. Playing deep bass Reggae it does bass well with a tight controlled sound suggesting the design is a good one, if it's just a bit tamed, compared to the fresher sound of the 1965-69 era amps. Differentials always seem to be the cause of the safe sound & for 2 sets of diffs rather a lot of pf caps are needed to contain it. The fresh high treble seems to be softened on known tracks which trying the IC tone stage can alter this but the fidelity is way off on this tone. If this was our amp, tempting to get rid of the power limiting stage but with the IC tone stage it'll still be there. Certainly some good design in this amp if ultimately to try a later model without the IC & limiters is our advanced view. A more down-to-earth view is it has enough grunt for Rock & Reggae & will please. We'll play it for a while then try the Sansui AU-G90X. The 90X sounded a bit like this did before we upgraded it. The 90X has a tighter sound but is so detailed it shows a far deeper dynamic range to the sound. Adjustments done it gives 32v clean sine output, 72w isn't what you can expect in reality, a 48w amp can match this, so treat it as a 55w-60w amp in use. On our Tannoy Golds this actually sounds as good as the Trio TK-140X from 1969 if both set flat, the only difference is the 8080 doesn't really do much on the Tone as rated ±7.5dB gain, the TK-140X is ±10dB and gives a far better match. Our rating of "Excellent" is the highest we'll give to keep it realistic, certainly excellence is here if the Tone Stage is really only 'average' & can't be improved. BUY-RAW RATING: Good if the open grille means it'll be dirty inside. COOL RATING: 6 the origins of early 1980s non-silver amps solidly made with well sized controls, you'd think it was more 1986 by looks until the heavy build quality is noticed. (2016)


1977 Akai AA-1030 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 30w.
FC, DIFF. Adequate silver fronted amp that could upgrade up well, but it was just nothing special at all but certainly not bad either & well enough made, not just a one board job. A higher powered model would give us a better idea. Is that all we wrote? Construction was typical for the era & midprice type but overall just another general amp of good enough quality. Just not very inspiring, we didn't touch Akai until the 1966 AA-7000 above & now see the brand as underrated, as were JVC & Yamaha before we wrote how good they were. These were commonly found in the Discount stores as the mag ads reveal. •UPDATE: Not had one of these since, but we've since got three earlier Akai from 1966-72 & these show where the quality in this amp started out, but this one was despite 30w the lower end model. Didn't fancy upgrading this when we had it in 2012, the construction looked less promising as do most 1977-79 amps & the sound to only get this rating will have been fairly unexceptional, if Mid Priced still & the AA-1050 was the 50w top range one, pity they didn't do 75w-100w ones to compete with Pioneer & Yamaha, we reckon there is still quality in these Akai, despite the later 1980s gear not having much cred & getting mixed up with Aiwa doesn't help, Akai quality as the 1966-72 ones prove, Aiwa appears a cut-price brand today & by the 1980s, but seeing impressive 1976 ads for their cassette decks, once again early Aiwa may be worthwhile. Maybe we should get an AA-1050? The AA-1175 is a 75w one & the Akai AA-1200 is a 120w from 1978-79, no ICs & looks a good design. BUY-RAW RATING: Good. COOL RATING: 6 typical product of the era as undistinguished as the amp itself if smart enough. (2012)


1977 B+O Beomaster 4400 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Very Good. 50w.
FC, DIFF, Darlington outputs. A more recent look at this amp since the ones we had early on reveals this is a superior amp to the Beomaster 3000(-2) & 4000 with higher power. Sleek looks still in the 3000 style & at last better buttons that are lighter to use. Construction is still quite crude & a lot of circuitry is crammed in quite insanely on the preamp stages. But having recapped one fully, the sound is much more punchy than the 4000 we recapped too with a good loud volume less restrained. But the cramped design does quite limit how we can upgrade & the amount of tiny ceramics was a job too far. The phono-preamp board still has spaces for Phono sockets but the 4400 never used them. Build quality is better than the 3000 & 4000 with lighter levers & the sliders are metal encased. Some odd construction such as axial caps up on end with the wire bent over as space was too low to use all Red caps, which are usually long past their best. B+O are very overrated beyond the 3000, 4000 & 4400. But as is typical with B+O, you can't say they don't look smart in nice grade with Rosewood or rarer with the Teak lids, certainly the best looking of the early design ranges. The sound all original is based on one with good capacitors & of little use, as with the 3000 the quality can vary once used more though there are no BC147s to affect. Once fully recapped & serviced the sound was much improved. It's not going to better the Big Brands for ultimate sound after upgrading but does do better than we expected so gets a nice rating. The Tuner is good on these Beomasters & the 4400 goes the full 88-108. The 4400 betters the 4000 on using Aux inputs, but the Tuner sounds quite similar. A 1978 B+O ad for this amp is a little bizarre "The transistorised receiver for those who still prefer valves". Yes it really suggests it has Valve capabilities in it's design, as well as misleading those who think it does have valves. The ad goes on about technical spec, ideas some put forward in 1976 about lack of musicality in audio & the 'transistor sound' yet only suggests the 4400 is as musical as a valve amp with the doubled output stages. Our less than excited verdicts above shows B+O are talking out of their behinds just a little. BUY-RAW RATING: Good but beware faulty ones as it's awful to work on & the Red capacitors are usually past their best. COOL RATING: 8 based on the Beomaster 3000 if bigger, has a certain look of opulence & confidence. (2014)


1977 Marantz 1090 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Very Good-Excellent. 45w.
FC, DIFF, FET. The one down from the 61w 1122DC reviewed next below is this 45w version. Marantz always different designs in each amp, 1090, 1122DC & 1152DC so different. Just to try another 1977 one after the 185w 2385 one. 1090 is built on 2 main boards midway in the case with the Tone sliders board on the front panel. Front Panel Fascia has the nice symmetry if not the extra panel depth as the 1122DC. This style goes back to their 1960s Preamps. Big Controls are nicer to use than the 15mm rotary ones, the Rotary for Tone is Tone On or Off plus Loudness when Tone on. Sliders not as precise in use as to always overshoot the setting you want. Rear Panel has 2x Phono, Aux, Tape 1 & 2 as Phono sockets or DIN. The 1977 type bare wire connectors on bigger push buttons & the Multivoltage block. Inside. Two main boards midway in the case with 6800µf 50v main capacitors oddly perched on the edge of the Preamp board & it uses TO-220 type power Transistors, if with side flanges. Ribbon cables from connector board to selector-preamp board must be a first in Hifi. a 1977 amp showing what became the standard Hifi build by 1979 & still is, beyond today's surface mount tech. Ribbon cables connect pre & main board & also Pre to Tone, only short pieces, if a step away from Traditional amp build. Marantz did lead the way with minimising cables with Track for Audio Signals, if the 1972 Luxman FQ 900 used long track on it's inputs side board. Updated but still the Marantz 1977 quality boards as in the big 2385. whether we like it is to be found. This typed after seeing the Marantz 4230, very different style. Heatsink as a box shape around the big Transformer, looks 60w+ size like the 1122DC one. There's Not Much In It. No complex power supply or Relay here, a big step away from the 1122DC style. Design looking at the Circuits is much simplified compared to the 1122DC & 1152DC. Simpler is better on some amps, if this looks very lacking inside, part of the Power Supply is half hidden under the Tape Monitor rod. Phono on 3 transistors, to Volume & Balance, then Preamp with Tone on 3 transistors. Beware the pdf adds Marantz 1050 pages to confuse. NFB on the Preamp, if as a Midprice Model to give a certain sound by 1977. Rather a lot of low value pf capacitors on both boards is how design was by then, to tidy corners left by cost cutting. Sound As Original. Clean but Bass Light sound as the insides suggest. This one has fascia corner damage plus the Multivoltage took a knock so we had to solder it as 240v only on both sides & glue it to keep safe, if an owner could still replace the part as screws hold it to the case still. To get a replacement Fascia for $25 from USA could have been ours a week before we got this, if to search for another. Behind the fascia is fine as we'll show on selling. Not so keen on the Design as a type of build used into the 1990s until Surface Mount tech arrived, but what it Sounds Like Upgraded to be discovered, it's what matters. The boards are not unlike the 1122DC if the construction on limited space is a bit away. What To Do With It? It's like Later amps for the Build, track & ribbons instead of longer wires, which is best? The design looks decent but the Budget type spec of the amp isn't good, if to better it to a degree if space limited. NFB on 2 stages beyond the Power Amp not our Sound if done well they can still sound Good for a Domestic Sound. But Marantz have a certain Look, a High Rating by others but to see £800 on a raw one, overpriced for sure when £300 is typical. Ours just needs a Fascia Swap & Recap-Upgraded you'll have a much better one, so Fascia knocks won't downprice ours much, as $100 would get you one someday. Upgrading. To give it some Upgrades to see how it does if to keep it at a price on this one. What it sounds like probably is much like other Marantz if how Bassy & Punchy it is to be found out. Not so sure on this one, it's a bit Alien in design. Try as Pre & Power Supply done. Sounds pretty decent, bit of Bass now. Marantz never sound bad, the later build style doesn't lose the 1977 range sound, so play a bit longer as the sound is decent, well crafted & our upgrades much improve it. Rock sounds good with a confident sound. Pleased for the Sound so far & still the power amp to do. All Recapped & Upgraded. Much improved from the thin original sound with no Bass, now it is with a Fuller sound. The NFB keeps it tidy if not squashing the sound, still a lively sound. 45w in 1977 a Medium Power. Fits in well with the other 1977 ones, not their highest model but a Good Taste of Marantz. Better than Expected, probably not one to Party Hard as not got the high power weight of sound as you'd not expect. These sold well at the time if as Original it's a bit weedy which has us not being too sure initially. This Upgraded does well & could go better for higher fidelity taking a lot to be that, our Ratings fair for what we've heard & a lot better than other post 1974 amps. On Speakers. Test for DC offset which is spot on, not adjusted before if Recapped now. Sound is decent & matches our Tannoys as the M 2385 did, sounding much the same once just Recapped to a similar level. Better sounds than it looks inside for sure. BUY-RAW RATING: As with any 1977 amp it's now over 40 years old, may work right & then not next time after a long session. COOL RATING: 7 smart looks improved with a Wood Case Repro one. (2019-20)


1977 Marantz 1122DC amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: See Text. 61w.
FC, DIFF, FET. Based on the 1152DC review below, why are we trying this, you may wonder. We wish we hadn't bothered is the final verdict, if we gave it a chance. We'll leave the review, if 1122DC is best avoided, in terms of Upgrading & even Servicing. Review. Buying Marantz needs care, these were often used their whole life, so to beware damage & repairs. The 1977 Range are not all good if 1090 & 2385 we had no issues with. Sound As Original & Untouched. We can hear the better Preamp without the poor 1152DC type Filters. The amp sounds smooth, treble is crisp if Bass is rather lacking. Sounds fine in a typical "Cardboardy" way that amps usually do from limitations. Far more crisp sounding than the 2385 as raw & original. Still a nice sound, wide stereo with a smooth sound balance without lumpy Bass. Depth in the Sound is lacking, making tracks sound a bit samey when we know them with more Detail on other amps, tracks are rather flat & lack the True Wide Dynamics other amps can. Design. The Power Amp has Doubled Output Transistors, not TO3 size, these are a variant of a typical Medium Power Transistor TO-220 with side flanges, 2SD588 & 2SA618 are 80w 7A if the datasheets don't give them a case style number. Horrible way of Push-In Fan-Type connectors on Output Transistors, these are the big problem. Doubled Outputs as 61w working on ±46v HT seems underrated on power. The Power Amp has what looks like 4 differential stages per channel, why is probably to get THD down very low, IM distortion of 0.03% is quoted as is a Damping Factor of 60. Slew Rate isn't quoted if the amp sounds a lot faster than a typical Stodgy Marantz sound. Power Supply is not good, cramped narrow board right by the Power Amp seems sloppy, an early hint the amp isn't so good, but we have to try it. The Board itself has parts underneath & added-altered parts which is lousy. Transformer is as big as 100w ones, 10000µf 50v main capacitors is typical of the era, if the rest is just 2 regulators. The amp needs totally taking apart, a lack of thought for a tech to repair. The Gimmicky "DC" feature is just adding a 10µf coupling capacitor after the Filter stages, which come from the Preamp which has it's own Coupling Capacitor so it's a pointless idea. The "DC" feature is actually not a good idea, it makes zero difference to the sound & with "AC Coupling" adding the capacitor it's safer for the amp, let alone using the Power In from a different amp that may have stray DC to cause problems. Playing It As Original & Now Serviced. Wide Stereo, Bass still light as nothing else done if adding Bass Tone helps. To hear the Treble a bit grainy is typical 1977. Beyond Deep Bass & High Treble the Sound is unusually Good for an Original amp which is why we continued. First Try after Redoing all except Power amp. Played it a bit, sort of a very low mainsy-hum noise as appeared after using it once, if this didn't totally go also it's a bit blurry sounding with very low Bass. Tried it Pre Out to another amp to hear it was fine. Do The Power Amp. Not much to do on the Power Amp if to take it apart revealed the horrors of build. The power amp board so cramped with weak track & the horrible plug in Output transistors says to not try more with this one. But then to Repair it once, twice, three times & lose the awful Transistor plugs got it going right again. What's it like on Speakers? Initially to think it was Great was short lived as the bad output transistor contacts failed in use, the sound quality faded away & it started to run very hot, Transistor plugs failing. It Matched Tannoy Golds spot on, no need for Midrange altering. Crisp sound with very lively Bass so it sounded promising. But still some low Background noise. Further Listening tells too many Differentials, the sound is clean but too flat. Move it on to cover costs, don't like it to put on this site even, so get rid. The Marantz 2385 & Marantz 1090 were good amps to work on & in use. We'll stick to the Earlier Marantz, the 1977 ones are not so good on some. The Receivers have more space, if 1122DC spacing was lousy, big space on the left yet the feeble power supply, just poor design. Had many 1977 or later amps, this just felt a wrong design from seeing it first time. From the 2265B review below... "The construction is a bit budget in places compared to how well made similar age Yamahas & Pioneers are made." By 1977 Marantz were more cost cut than Pioneer as they were Comet Discounted. BUY-RAW RATING: As with any 1977 amp it's now over 40 years old, may work right & then not next time after a long session. Construction Issues may cause big problems. COOL RATING: 8 smart looks improved with a Wood Case Repro one. (2019-2020)


1977 Marantz 1152DC amplifier ↑
AS-ORIGINAL (Once Serviced): --. UPGRADED: --. 76w.
FC, DIFF, FET. Revised 2013 Opinion based on 2012 owning. Not Really A Review, so until we get another one, this will stay. We have previously put this amp down based on bad experiences with one early on that clearly was faulty. Ignoring the messed with amp we got & based on the ideas of receivers on this page being pretty good there are enough similarities to ignore the bad amp we had in our ratings, but to point out the issues. The oddly low-volume sound is otherwise decent, the volume before clipping on headphones for a 76w amp is pathetic & we couldn't do much with it in our earlier exploits. Bad construction design loose fully pinned boards & poor soldering throughout make this our least liked amp ever & it wasted much time & money. Looking at the circuit on adding the FC, DIFF notes, the circuit is awful, multiple Differentials in all stages & other excesses explain the poor sound. Ridiculously overdesigned in search of meaningless specs, and musically void. We noted it had a deep bass on recapping it, if the midrange was 'cardboardy' and the treble was rough even once biased right. Not one we'll try again willingly, but horses that threw you need a new ride or it spoils you. Overall, based on the 2 receivers, Marantz have a big name but the sound often isn't as good as others from the era & Marantz always seem overpriced therefore. Would we try another Marantz amp to update the 2012 opinion? Yes, if not this one. Many are findable, but are very overpriced for the power rating, this 76w one is rarely seen if the 10w-30w ones are. 2020 Opinion. This Review is based on a faulty amp. Volume Gain was poor. Maybe we'll get a 1152DC depending on the 1122DC opinion, if this review as 2012 isn't much use really. 1090 is straightforward, 1122DC has quite a bit of overdesign if good Filters. The 1152DC filters like the 2385 are not good. Seems Marantz used very varied designs on their ranges. BUY-RAW RATING: Risky due to bad soldering & poor connections on top board. Complex amp as is the 1122DC above. COOL RATING: 7 always better in the wood cases, has a certain confident look, without the case dips a point. (2012)


1977 Marantz 2265B receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 65w.
FC, DIFF. Sweeter sounding than the 2245 & a bit of an exception to the rule that later is worse. Compares well with the Pioneers & Sonys above even all original & certainly surprised us. But we sold ours on quickly as others bettered it. Are they worth the money they sell for today? yes, as others are too cheap in comparison,, but many of the low power ones get overpriced & go unsold. Ours was damaged on one channel & needed a lot of parts [16] replaced showing there are no fuses or much to save almost trashing the amp which is a bit of a worry as is the useless plastic on the bulb fascia which will break away as aged from years of bulb heat. The circuit is much better than the awful 1152DC amp above & see how the ratings are better for it. The construction is a bit budget in places compared to how well made similar age Yamahas & Pioneers are made. BUY-RAW RATING: Good. COOL RATING: 8 in the wood case, a bit plain without it so 7 if the blue lights on silver look smart to take it above the Pioneer looks. Later ones now with the cute hex nuts but Marantz stuck with this design for so long as it is just so right. (2013)


1977 NAD 300 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Recommended. 80w.
FC preamp, several DIFF, DT. Appears a huge impressive & classy amp with useless Dolby stage let down by a less than acceptable power amp stage & odd wiring routing, FET preamp { 2022: can't see FETs in a more recent circuit diagram...? } delivers a fine if un-upgradeable sound but the power amp section is just not very good and keeps it's ranking lower than the 22kg bulk of it suggests. Sadly it has the overheating power supply with hot regulators hidden away with no ventilation that mess up the PCB even. It also doesn't play very loud, the NAD 160 plays louder than this easily. "Going past the 1 o'clock position it's not very loud and the stupid thing starts distorting, yet it's 100w." we wrote originally. A disappointing buy after the NAD 160 quality & the NAD 200 big amp version we hear is similarly low on the volume. Only one not-very-good way to get more volume & that upsets the output severely as the power amp is a poor design as evidenced by the last minute chops to the design. This should be a winner, but several things keep it down, overdesign is the problem very noticeably. Probably our most disappointing upgrade. For the big classy unit this looks, the inside technology is just not very good at all. Would we get another one to revise the opinion? We can now see why it plays so low volume, the Luxman R-1040 has the same issue & solution. It or the NAD 200 amplifier are rare amps to find, but in light of new knowledge, perhaps it needs another look. Seeing another on ebay 2017, it just wasn't very good compared to the NAD 160. Volume was weak, the Dolby could be problematic, bad soldering on overheating power supply & all FET preamp {??} didn't allow much upgrade, FETs have no place in a preamp as the spec is too limited. Huge 22kg amp looks impressive, but it had poor cabling that picked up hum as audio went right by the power supply. We last had one 5 years earlier but found it frustrating. Knowing the problems with amps stops us wanting to try another one. BUY-RAW RATING: Good if power supply overheats like the NAD 160 does. COOL RATING: 8 classy looking huge receiver with glossy black lid, no wood case on this one, still with NAD 160 friendly looks. (2012)


1977 Rotel RX-1603 Monster Receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Very Good-Excellent. 180w
SC, DIFF. We Blogged about this on the Sept 2018 blog & a Customer sends us one to upgrade later that month. Our Opinion of it was cautiously positive as not really seeing enough of the insides & the Service Manual is too Blurry to read values, if Rotel are usually very worthwhile even on their more Budget-Midprice amps from the early 1970s. We've not opened our one yet & just put it on the desk which shows how Huge this is 60cm wide, 18cm high & 48cm deep. It's Big. It weighs 33kg with the main weight at the rear. It's Big. The Tuner Knob is 55mm wide & the other control knobs are larger than any other amp we've had. This cost £701+15% VAT by 1979 so £806 if was £570 in the April 1977 Hifi New/RR Review of it. the obvious comparison is the 'smaller' 185w Marantz 2385 that was £977 +VAT so £1123. Both hefty units for a hefty price. The one we have was owned by a Hard Rock guy who must have been doing well in 1978 when in his late 20s to buy this & one-owner grade on such a big amp seems unusual. Wouldn't say it got a lot of use by the grade & by the dust around the screws, it's not been opened before. All complete which is what a high grade one brings. Original Owner played Records if the 4 Phono blanking plugs are still fitted so will have used DIN cables for phono & Tape. The rear Power Amp section is full of dust & realy shouldn't be plugged in until cleaned & serviced for the risks of damage, it might not have been used this century for all we know. Speaker Sets x3 are on a Hole & Screw type fitting. better grip than Springs if still only for thin wire, to use 4mm cable blocks, to put 4mm connectors on an amp like this not needed really, if they could be done. Plug wired well if still a 13A fuse, a 5A one is correct. UK model with AC outlets blanked out. 144m round Transformer with 2 secondary windings for 5.5V AC for Bulbs & 2x 55v AC for the ±HT. Two large main capacitors with heavy duty screw connectors, 22000µf 80v is very high spec for 1977, outdoes the Marantz 2385. Output Transistors are Paralelled with 4 transistors per channel, the Marantz 2385 uses 6 per channel. The Rotel works on ±72.5v DC if the Marantz 2385 is ±75v, with both 180w-185w if double & triple outputs. We'll compare both amps on a Blog. Why is the amp so Big? Beyond the need to compete with Maranntz & Pioneer, the rear Power amp stage is well packed. The Front Tuner-Preamp half is quite spread out with enough free space to store £20k Cash if you needed to. the Amp splits into Two Parts, if only for Servicing, a few plugs & cable plugs will free it somehow. Rear rubber feet are more for stopping the amp going too close to the wall if not really for standing it up-end on. Underside covers off, the rear one only has dust in it & the side grille bits are part of the frame. Front part has the Preamp & Tuner parts plus the Power supply with a big Heatsink for two Regulators. The usual 'bits' for 1977 that Pioneer & Marantz use, as well as knowing these start failing by now. Power supply board is untidy with big 10w Resistor with Capacitors right next to it, not enough room? Beyond that it's all very nicely made, not unlike the 1971 Realistic-Hitachi on the Preamp Board, as good ideas got made standard. The Fuses & Relay are put on an upright board between the TX & main Caps, not very Service-friendly if the whole thing will come apart once being sure enough that it's safe to Plug in. The Preamp Inputs on the top middle won't look neat with stuff connected, if 2 thin DIN leads was not so bad, to use phono leads of today will be untidy, if better than some that put Connectors on the side like the 1979 Sansui G-8700DB or underneath like the 1982 small Luxman L-2 amp. Hi-Fi News Review. April 1977 has a Gordon J. King review, not a great reviewer we've found reading his other ones. It's reviewed with the NAD 300 & Pioneer SX-1250, we mentioned this as a "boring review" on the "Deciding..." page, it just reads the User Manual info almost plus saying it sounds good & drives speakers well if no mention of ESL ones, tells you nothing really. The tables show '11.5v/3µs' which likely has a "3" typo? Our listening will reveal as unlikely it'll be only 3.8v/µs. The review is hopeless, going on about TID Transient Intermodulation distortion, that was later revealed as not existing. Don't bother with the Reviews, avoid the NAD 300 as we didn't like that. Rotel or Pioneer by looks, Pioneer more reserved looks, Rotel with the handles probably more Bloke Appeal & both the same price it appears. Taking It Apart. Once in two parts it's at least going to be workable, some thought into this huge beast, if it could have been made smaller, but where's the fun in that? It Comes apart Into Two Pieces, but how? The side Heatsinks have a line of three big screws on the edge nearer the front, undo them, it comes apart. We did it with the amp on the side as the screws are almost seized so need a bit to undo without chewing screws. Then you find 5 connectors, two are Mains as M/F connectors plus three plug-in ones of 6, 9 & 10 pins. The Fascia has 10 screws, hex bolts for the control knobs, the Tuner has 2 inside only visible on the right edge & the Mic Mixing one has a smaller hex to undo. The Fascia is a hefty 4mm plate weighing 1.5kg with a perspex window. Build Quality. With the preamp half by itself minus the fascia, it's a little surprising to see the 410mm long preamp board is backed directly onto the Tuner & Switches board above it, metal casing would be thought needed to shield both of these, but not so say Rotel, if a small shield plate is soldered over the IC area. The top switches board is rather floppy in the casing, nothing to hold it secure needs sorting as it'll bounce with a Courier, other amps put a bit of rubber foam. The Preamp board also is rather thin with no support beyond the controls when fitted in. Tuner Pointer is vulnerable, tape over it to not break it off. An amp that needs care in handling when apart for sure. Penny pinching on the 4 screw holes for the front lever switch pairs, put just 2 screws, but this was 1977. If this was built with thick steel like Yamaha still did in 1977 then it'd be about 5kg heavier & with screws & covers done up it is still rigid, the start of the build quality you see today really. the selling point is the huge size, huge main caps & huge transformer. For the huge size, it'd be better designed as a Pre & Power Amp & go into a 2-Unit type of pricing. First Play Of It. Not as original as the Preamp front board was faulty, so we just recapped the lot as fault finding is pointless when it needs a proper recap. So to hear it recapped with our upgrades if nothing else changed beyond a service of the preamp half, power supply & power amp is still dusty as arrived. Sound of it is agreeable, but nothing special beyond it's fresh sound, Bass is nothing much, Stereo isn't very wide & the Soundstage is quite limited. Sounds no different to the cheaper 45w RX-603 below from remembering it. More to do on the amp, but it's rather modest sounding, compared to the 185w Marantz 2385. Turning it up a bit louder on Headphones, that Low Spec Pioneer sound is here too which is a bit disappointing. The Doubled Parallel outputs give a bit more Bass Grumble if the Midrange & Treble aren't well defined like the Marantz can do. Trying Rock Guitar it plays the sound on just the Guitar Riff fairly well, but the Bass weight isn't here at all & the treble detail of the rest of the track just is messy, playing Joan Jett 'Crimson & Clover' as the start has the hard Guitar. An amp to be played loud to hide how it mangles the finer sound, just like Pioneer SX-950 type amps, the cost cutting is noticeable & a bit of a pity really. 1960s Ska is harsh, Roland Alphonso 'Cleopatra' is not good on this amp & off it goes. All other known Test Tracks just don't deliver & fast treble is undefined & splashy. It doesn't even get down into Heavy Sub Bass, just plays it with no emotion. Why pretend it's any better, it's not unlistenable but it's no pleasure either. The Circuit Diagrams on the only Service Manual there seems to be are unreadable, A4 photocopy scanned too low res & incomplete, making upgrading tricky, you need circuits knowledge to make any sense of this & trying to repair one will be difficult. But ManualsLib has a far better version of the same Photocopy, so to get that. First Play Now Upgraded, Recapped & Serviced beyond Amp adjustments. Stereo width is much improved. Sounds fast & clean but Bass is still very weak here, it's 180w it should be rattling the Headphones, but even on known Bassy tracks it shies away. To even use the Bass Tone control on the 200Hz setting even at +10. To use the Soundcard EQ to add +8dB at 31Hz, +5dB at 62Hz & +2dB at 125Hz gives it what it's missing, some kick & to match how we remember the Marantz 2385 sounding, if adding EQ is never as good as having the Amp do Bass properly. This Bass gets the Heatsinks a little warmer to 34°C if we've not adjusted it yet until run in. With the EQ it's actually pretty decent, on Rock the 125Hz is better set to 0dB if the 31Hz at +10dB & 62Hz at +6dB, which is a full Bass Tone gain if it's still not quite right it's nearer to the 2385 & it needs altering on other tracks. To not play too long to listen to as the sound is EQ altered which can upset the hearing as we'bve found before on less-than-neutral amps. It's nearly done in reality to the paid job, but in the interests of getting an 'Excellent' from Upgrades if possible, to try more with this is needed. On Tannoy 15" Gold Speakers. To try it out, we take it in the other room in two pieces still for ease. It didn't like first turn-on & went straight into 'Overload' light mode after a noisy relay click, hardly reassuring on our speakers. To suggest you let the amp settle before switching speakers on which was fine on the next try. The Sound. After how thin it sounded on Headphones, on Speakers it's a lot better with a decent bass & wide Stereo. But that's all we can say good about it, it sounds awful is fair comment even after Servicing & Recap-Upgrading. It's overloud, it's flat & cardboardy sounding with high treble sounding untidy. We only just played the 1967 Pioneer SX-1000TD-F on the same TV shows & the Rotel gave an impression of what sounded wonderful on the Pioneer then mangled it. But That's Not Good Enough... So to get heavy with it, to Run It In for 6 hours one day, adjust it as it became warm on one heatsink & then run in another 9 hours the next day. Just tried it on the Tannoys again & the sound is hugely improved, the bad sound is gone replaced with a sweet if upfront sound that we play for more than 2 mins as before. Deep Bass isn't the strongest here, but it's worthy of a listen now instead of being disappointed with it. The thing is this particular amp was owned by the brother of the guy who brought it to us, he was at least 70 & his brother possibly older. By the high grade of the amp if very dusty inside, odds are it's sat not working in 30+ years by a radiator or in the window sunlight as Dust inside was like a Hoover Bag from heat-air circulating. It did have a fault with the preamp only working on one channel. The large capacitors will have sat unused which doesn't do them much good as with Cars left sitting over 10 years. What we have done with 15 hours running in is to 'Reform' the capacitor & here it's now good. Usually the Power Caps we upgrade but these are so huge to replace them could be over £150 plus to actually find suitable ones. Certainly unusual for an amp of this power to sit unused for so long if all amps we run in for at least 6 hours to be sure they are woken up & running well. This was an extreme example. The question is as the main caps were 'sleeping' they could be still below par & it's for the customer to either use it or spend heavy on more main caps to ensure it stays good. Only by cutting open capacitors can you really see how aged they are, some go dry & grow crystals to go crusty. Other Difficulties in this amp from the weakly supported Push Buttons-Tuner Board. Note Relay on the Fuse Board if 4 more on the Spealer Sockets rear board. The Rotel label at the back with Security screws hides a Multivoltage plug. New Main Caps Bought. Not as expensive as some this size can be, cutting open revealed the rear one was almost dry if the other was still wet. Running in 15 hours reformed a Bad Dry Capacitor. To replace therefore was needed. On our usual Clean Sine Output test it rate 52v on both L+R putting it with the 160w Sansui G8700DB, if the Marantz 2385 manages 56v. BUY-RAW RATING: Risk of failed preamp capacitors on our one, if the type used are typical 1977 era like Pioneer & Marantz. Needs a good long running in if left unused, the most extreme example of this we've had. COOL RATING: 5: The casework is neat & looks good cleaned up, big control knobs if that big tuner lit looks a bit less cool. It's far too huge, it might score high on Beery Bloke Appeal, but it's not an amp to consider lightly for the huge size & weight. (2018)


1977 Rotel RX-603 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Very Good-Excellent. 45w
SC, DIFF. Looks more 1972 inside from the design as the SC proves, pity the cheesy plastic front & handles, but a very good sound here. Pity Rotel didn't go higher power on earlier ones as they are decent sounding. The higher ones in the range have the similar looks & overbright display losing appeal to some, but the sound is pleasing. Cost cut as was typical, but still a nice design & for the decent sound one that would improve well & hints the bigger models will be worthwhile if the looks appeal. REVISITED: The last one had fascia condition issues so not worth upgrading, but the design was decent quality with a good basic sound, so another one just about Mint externally is worth upgrading. Still looks years earlier than 1977 inside if nicely made with no ICs beyond the Tuner. Not sure why a bridge rectifier needs a heatsink, it's not even warm as we'd expect. Transistor count per channel is Phono x2, Preamp is x3, Power Amp x8 with 4 extra as L+R protection. This is impressive for a 1977 amp. We didn't bother much with the earlier one as condition wasn't nice, but this is so gets more respect. 45w RMS min into 20Hz-20kHz if a 350w max VA rating shows spec is good here & upgrade potential is good. So to try & it is clean for the decent circuitry, wide stereo with no grain at all. No slouch on the bass either which is unusual, again a high grade amp with little use is a better amp on first try. As with all amps, the sound reveals cost-cutting on spec but for a raw amp, Yamaha don't sound this precise & detailed. It could be a case of 45w is the perfect wattage to get the cleanest sound unlike the higher power ones with more complex circuitry. As all original, it plays Rock guitar pretty well if lacking the ultimate weight of valves, it's not a blurry mess either. Playing it louder on Rock does reveal the low spec as it becomes a little harsh, but compared to some it's still very impressive. The Luxman R1040 was nothing like this for example. The Power Amp is oddly only Semi Complimentary, by 1974 most were FC. Big amp with boards well spaced inside if the power amp board is quite tight. Recapped with our upgrades brings it alive further, a clean accurate sound with much quality. It's not the most weighty sound as is typical of Differential era amps but bass is still good. Still one of the better post 1975 amps though if you like the looks. BUY-RAW RATING: Good if plastic handles intact & plastic fascia is good, else it looks tatty. COOL RATING: 6 on revisiting a Mint one without condition issues it looks so much smarter. The tuner lighting is a bit plain as are others in the series & the rack handles aren't everyone's taste but mint they are unoffensive. Not classy all-metal like Yamaha though. (2015)


1977 Sansui G-301/G-3000 receiver ↑
AS-ORIGINAL (Once Serviced): --. UPGRADED: --. 26w
SC, DIFF. Finally remembered which amp this was, G-301 same as G-3000. One we found by The Side Of A Road, as in a backstreet behind shops that was a quieter cut through to the Post Office. It sat waiting for the Binmen as it was their day probably. Not done Hifi for a while as busy with Vinyl, this maybe in 2001, time for a 2023 review. Picked it up on the way back & externally it was decent & complete, if typically filthy for it's bedsit status, but it was an old amp. Looking inside showed burnt resistors & a time before you could find Manuals online. A 10kg amp so considered worth picking up & the price was nice, free. Set about testing what was wrong & bought the parts. Got it going & it sounded good. Not one we had use for as had the Valve Amps & other ones around then, but the idea was fix it up & sell it as a working amp just for the trying of it, only worth about £40 at the time & it sold. Today we'd recap it properly & understand why it was like it was until it was on for a minute. Typical 1977-79 looks with the square buttons. Inside in that typical style, one Tuner board & one for everything else, to see online photos now it's not a bad amp for a 26w 1977 one. Ebay shows bids £100-£180 if other oddly high prices that are best not considered real. Shows it's in the typical Auction Price for better vintage amps that are original needing a recap. The rear panel with the dust collector 'shelf' for the controls as they are soldered direct to the PCB & more plastic casing. A litle cheesy in style perhaps, has the ribbon connector cables instead of better shielded cable, but the fact we spent to get the parts it was seen as worth the effort. Used to buy amps at Car Boot Sales in the early 1990s, some are now Money ones but always £20 for nice stuff like Marantz & Harmon-Kardon. Remember getting a blue Meters Pioneer amp one found in the bin as the volume control was loose, too much for 'Cash Converters' to tighten it. One of the IC output block early 1980s ones. (2005-2023)


1977 Yamaha CA-1010 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 100w + 20w Class A
FC, many DIFF, DT. Hefty 100w Yamaha amplifier. Offers Class A in the Power Amp & nice meters. Looking later as we go through the FC, DIFF notations, Phono is Push-Pull with 9 transistors, an IC for MC & 2 differential pairs, Preamp-Tone is 10 transistors, push-pull with 3 differential pairs, but this is a challenge to see what we can do with it, as we didn't like it much before. Power amp is 21 transistors, 2 differential pairs & doubled output transistors. Getting one back again, it's an impressively large amplifier, the faceplate is 460mm x 150mm. The front with the big needle meters & well placed controls is a nice amp to use as are Yamaha usually. The user manual shows a different wattage of 90w+18w but the Service manual states 100w+20w. A well made amp as the one on the Solds page shows, the CA-810 lacks the class of this. In terms of build quality, this is what we like to see & apart from the power supply hidden underneath to get hot, blackening it undeneath. Very first play is nothing like the earlier opinion, the total opposite actually. The sound for an unserviced original amp is balanced & clean. Bass is certainly here with known bassy tracks doing deep bass very nicely with no sign of brightness or bass-lightness as we always got with the previous one, no thickness or unnaturalness. The way it plays deep bass is a bit of a joy actually, not heard many transistor amps sound like that. There has to be something to getting high grade little used amps as the latest CR-2020 proved too as it sounded very different. Trying Class A was interesting. Starting off in Class A it was cleaner & more precise with the same tonal qualities, flicking back to Normal (Class AB) was noticeably reduced & back to Class A was an obvious tightening of the sound. But we've had Yamaha Class A amps before & once we've upgraded the amp, the difference becomes almost impossible to tell apart, as per the CA-800II above. Well after playing this high grade amp, it's rubbished our earlier opinion of the amp, but that is sometimes the game of Hifi, needing another one to be sure of the opinions. The last CA-1010 we couldn't play for very long as it was so rough sounding, this one we can play for 30 mins easily even unserviced, even the CR-2020 as original we found a bit edgy. But even in Class A, we can hear there is weaknesses in the sound, ceramics are always in Yamaha amps. Trebly Rock reveals this more, but listening through that, the sound is still balanced. This is a loud amp, a kicking track like Jam 'Start' on 3 on the volume doesn't quite hit 10w but is as loud as you'd want it on headphones. We'll service it & compare to other amps before we rate it again, but this is unexpectedly good. The doubled output transistors add to the current to give more kick & the circuit is designed to take better advantage of this. Got to try it on the Tannoys to see how it matches... thankfully they match very well, leaving the 1971-75 Yamahas possibly not a good match to earlier speakers. Compared to a recapped CR-2020, which is crisper for the upgrades, the sound is as wide on Stereo with a lively sound. The Doubled Transistors add an extra solidness to the sound as does the 1965 Sony TA-1120 that has doubled outputs. Class A makes absolutely no difference on Speakers though. Looking inside, the power amp board is neater than other Yamahas but has 14 ceramics per side which add to the rough sound as it ages, but we upgraded them on the last one & it still sounded rough. 2SA745B & 2SC1403B output transistors are 70w rated, an odd choice, if doubled they'll give the higher wattage. After servicing it sounds crisper if the nice bass is still there. Now it's rather like the CR-1000 for the louder Pro-Sound if this still sounds very clean on Class AB mode. We did have trouble with the CR-1000 on the M20 headphones too as it was too harsh & thin, the CR-1000 has got revisited already. It appears this is more the reason why in some way, but this one is cleanly focussed on treble, the previous one was raggedy. Of all the 1973-77 Yamahas, this is the only one not overpacked on small boards. The preamp-tone has what seems like a lot of transistors, but it's nearly all direct coupled, 2 FETs, others are not so obvious, but likely 2 power supply, 2 drivers, 4 push-pull output-buffer stage, complex but a very clean sound for it. Power amp shows high impedance is used here, with 21 transistors looking excessive, but again it relies on many of these for regulation & Class A use, ignore those and doubled output transistors adding to the count & the circuit is actually fine. But understanding what many do likely is the basis of what we see put into later ICs with Current Mirrors etc but done in transistors. Phono has MC input with an IC & the MM stage has another IC, these are 1G164 (or 00164) and Y-K100 67, total unknowns though we suspect they are a differential pair in an IC instead of transistors, an odd choice as space isn't an issue. The design once unravelled more is actually a very advanced design yet it still sounds like the CR-1000 if noticeably cleaner. No Loudness setting to tame the powerful sound on this amp. To rate this less than Excellent now Serviced would be wrong, the Pro-Sound volume & it can sound 'Clinical' on the wrong sort of small speakers as you need 15" ones to do the sound justice. Buy it to use right & Excellent it is, but it could be too good for most speakers is the caveat here. It was taken on by the 1984 Sansui below that seemed 'better' but as with all testing, it goes back & forth a few times, but now this Yamaha beats the Sansui with ease. The CA-1010 upgraded is awesome. In comparison to the CR-2020 upgraded at the same time, they are obviously quite similar, if the CA-1010 is more neutral. BUY-RAW RATING: Good, some minor overheating underneath though if not as severe as the CR-2020 so no issues here. COOL RATING: 8 again the blokey minimalist looks but classy, pity these only had the flush lid, the CA-1000 type bigger case looks nicer. (2012-2015)


1977 Yamaha CA-610 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent. 40w
FC, DIFF, DT. **See below for a Warning** Decent 40w version of the CA-1010 above, £142 in 1978 HFYB. First thing we noticed was the Circuits have a sensible Preamp, none of the OTT design that makes the CA-1010 thin sounding, if we last had that one 6 years ago. This nearly the size of the CA-1010, no Class A stage if looks the part. Seems the 45w CA-710 replaced it as others in the range lasted until 1980. ICs in this CA-610 if not the CA-710, much used TA7136P ones, the huge volume control knob like the CR-2020 tuner one looks more purposeful & a better layout on the CA-610. The CA-610 II swiftly arrived with 'Aug 1977' dating, no ICs & 'Direct' ideas to keep up to date. HFE has an (incorrect) comment saying the sound is 'clinical' which from knowing the CA-1010 means bright balance with not much bass, the receivers were better sellers as a richer sound. Lid off it's like no other Yamaha, transistor outputs on a large heatsink plate. Transformer & Phono stage with long rods for the selectors. For such a big amp, the Preamp, Power Amp & Power Supply a bit cramped if predates the 1978 Marantz 1072 for the '1979' style boards. 45v 6800µf main caps is decent spec. Phono & Pre ICs typical designs, NFB tone, no Pre Out-Main in unusually, into Differential Power Amp, with NFB on the Diffs as seen on a few amps now. It sits in front of us as we type, smart looking unit with Vinyl Wrap, a bit bigger case than it need be. Power Amp can be fitted smaller for the new 1977 size driver transistors so as with the Marantz 1072 it's still a decent amp. What Does It Sound Like? Turns on fine, meter bulbs to replace maybe with LEDs? Sounds reasonable, not Clinical at all, there is a rich sound here if a little artificial sounding. Narrow on Stereo, a little compressed, if we've been playing much livelier amps in the last week, this is a little 'domestic' sounding. On Rock it's got detail if rather flat & cardboardy sounding, dynamics kept neatly boxed. The treble is a little soft, if all created to sound good value when new. Compared to the Marantz 1072 & 1090 it's a little less fresh so dips half a rating, if otherwise fairly similar. What's Inside? Front off reveals 1977 Yamaha build on more Budget Amps, made by the CR-2020 factory if things just done 'more economically' if some are not possible to cost cut. PCB is 2 boards with joining wires soldered. The front stage is divided into named sections which we've not seen with Yamaha. The left side is a very cramped Power Supply-Relay stage if Meter & Main LCH & RCH are more like the Marantz 1072. Save a few screws & bolts so the selectors wobble free if circlips to hold steady. Phono on the rear PCB part has lots of space if the Tone-Pre is tucked right at the front with the ICs. Build style more like the CR-820 than the CR-400, us knowing the Top Range ones if it's priced to a point as by 1977 so much competition. We know the CA-1010, there are CA-810 & CA-710 above it. 40w in 1973 was higher power, by 1977 it's midprice. Interesting to see how they did the lower models which are without the overdesign of higher models, if the cost cutting is a bit harsh, it has a lot of ceramics in this amp, if beyond the upgrade job level we're doing here. Sort of has the feel of the Marantz 1072, it should sound good upgraded for what it is. Now Upgraded. It plays, if surprisingly upgrades show it's a bit lacking. The Sound is rather flat & the Ceramics grain sounds, if Headphones are very revealing. It'll suit Midprice Speakers if we'll try it on our Tannoys once adjusted. No Heat on the Heatsink, quiet background & Relay on with ease. 1977 Hifi isn't our Bag for having so many 1966-73 era winners. IC phono & preamp-tone were updated to Transistors with the CA-610 II. The similar Marantz 1072 from 1977 not so unlike this if the Marantz had a fresher sound with similar upgrades. Still it cleaned up nicely & has a smart look. To run it in, test & try more. Run It In thankfully brings a better sound, bit worried this wouldn't be so good, after all amps past 1977 can be too cost cut, if this is a Yamaha. The flat sound now improved & the grainy sound is now far more listenable. The Treble is very crisp & precise which actually isn't a usual Yamaha sound, the ICs are no problem in the Preamp. Bass could be better, as in better deep bass power, if with many Yamahas here to never get the 1969-era type bass in them. Punchy Fast sound, if +1 on Bass suits us. Wide Stereo. Rock with the usual JJ tracks is surprisingly good, +1.5 on Bass gives a solid sound & again precise punchy sound not blurry. For a 40w Yamaha, it's better than expected, not as weighty as higher power ones if far from a junk IC amp, if ones of later years can be hideous. A Lower Model Yamaha. Still a good amp, cost cut to a degree if the ICs aren't a problem. First use on Speakers it was rather off balance, as in Balance '2' to the right. To test it to see 28v clean Sine is a healthy 40w. The meters have no adjust, only the DC offset has a pot. Meters within Tolerance as is the Power Output. To be ultra fussy Balance is spot on matched with Balance '0.25' to the right. This is actually typical of most amps. You pay more & get better matched Volume Controls etc. A good amp to know & go be fussy about. On our Speakers like most Yamaha, not the best sound match to 1968 Tannoys if a 1977 amp of this status would never see such speakers. **Warning: This amp is very cheaply made, the CA-610 II replaced it very quickly the same year. The problem is Construction is weak to the Point the one we had got Courier Damage twice resulting in Broken Links & needing repair. It's held together only by soldering instead of a proper frame. The CR-820 we found a pain similarly in 2014 so never bought any later Yamaha. Weak Soldering is very poor to see here. For the fact the Customer or Us wouldn't expect this from a Yamaha means this amp is best avoided. You too will get a terrible customer who blames you for their bad amp choice when it causes problems. Yet it sells for £400 as it looks decent outside but crap inside. BUY-RAW RATING: Generally good, runs cool. High risk of Damage if sent by Courier as poorly made. COOL RATING: 7 smart fascia ups the score, neat vinyl wrap looks like the higher models. (2021)


1977 Yamaha CR-820 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 55w
FC, DIFF. Very like the CR-2020 if less power, one of the sweetest sounding silver Yamaha as in playing all-original ones, with the CR-800 just ahead & a Very Good buy as they seem to have sold well when new. The CR-800 & CR-820 are wise buys with fine sound if you don't want the bigger models. The 1977 ranges were cheaper made than the earlier ones, but this was how Hifi was by then. Not one we'd try upgrading for the one tightly packed board layout is only really optimised for the spec used & there are a few regulators that are a bit hot as was usual with Yamaha. Don't even bother with the CR-840 as it has a glut of ICs as Yamaha unwisely relied heavily on for the next range. BUY-RAW RATING: Good. COOL RATING: 7 typical Yamaha looks if the silly row of buttons loses it appeal. (really?) (2013)


1977 Yamaha CR-1020 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 70w
FC, DIFF. Less powerful 70w to the CR-2020 if really no obvious difference in sound to the CR-2020 beyond power rating & will have similar upgrade potential. As found much used it is clean & punchy but usually warm & soft on fine detail that is a bit disappointing keeping most 1020s as a 'Very Good', if not always. Only a high grade little used one rates the higher 'G-E', if these are rare. These sold well but often got used to excesses, look for dark marks on the top grille for the party-hearty ones though all can be rebuilt. We've never upgraded the CR-1020, only having one in 2012 that was like new, but it is so similar to the CR-2020 the same rating will apply. See the CR-2020 below for more on this fine amp. Don't even bother with the CR-1040 as it has a glut of ICs as Yamaha unwisely relied heavily on for the next range. So similar to the CR-2020, read further there. REVISITED: The CR-1020 is usually multivoltage, the CR-2020 is usually only one voltage as the transformer would be too big. Having a 1020 here at the same time as the revised 2020 opinion one, the sound really is no different on a high grade one & the 70w to 110w difference would only be noticed with very inefficient speakers. The CR-1020 looks a little bare, or more minimal, as it lacks all the CR-2020 buttons such as Tone variants & defeat & the FM blend, muting & OTS features, as well as a few extra LEDs for them, but are they that important anyway? The 2020 is found more readily than the 1020. Phono just lacks the MC stage leaving the Phono section at the back of the Tuner board partly empty, else the rest is the same. We had a CR-1020 bought in Singapore that was multivoltage & in the big USA style case, probably this was the Japan home model. It had a bill of sale for early 1981 from the Yamaha shop & the buyer got it for a remarkable S$645 which was just £135 as an end of range item by then, oh how wrong Yamaha were. The International Guarantee card gives 12 months warranty with exceptions on fragile external parts as wood & glass, items usually long lost but in the original box of this one, a huge 67x51x29cm sized box with 2 large polystyrene clam parts & hard card square tubes in the corner, neat. Sounds the same as the CR-2020 on the Tannoy Gold speakers. BUY-RAW RATING: Risky as power supply overheating will need repair with no exceptions. COOL RATING: 8 more smart Yamaha looks, a big impressive amp & even better in the big USA style wood case. (2015)


1977 Yamaha CR-2020 receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 110w
FC, DIFF. Has to be the best ever of the post 1974 receivers for sound & 110w is a powerhouse but always in need of work as it overheats on the power supply. Sound is sweeter & richer than the CA-1010. First appears in shop ads by Sept 1977. As found much used it is clean & punchy but usually warm & soft on fine detail that is a bit disappointing keeping most 2020s as a 'Very Good', if not always, see below. Only a high grade little used one rates the higher, if these are rare. It can be upgraded into something much better than the poriginal sound, in 'Excellent' territory. Build quality not quite in the league of the CR-1000 though this is a 1977 design but is one of the best post 1974 receivers after upgrading. The phono board on the tuner board is a bit of a cheapout, but for 1977 perhaps these are the best receivers for realistic prices. Other brands were using ICs even on top items, Yamaha only uses an IC for the MC stage. Looks even better in the big USA full case, though the USA model adds Dolby FM input but is 117v only. We had a CR-1020 bought in Singapore that was multivoltage & in the big case. The CR-1020 is usually multivoltage, the CR-2020 is usually only one voltage as the transformer would be too big. An amp often found in lesser grade as well used & usually failing sooner or later is the risk. REVISITED: Getting another one after being without one for a while, to try this afresh. The usual overheating issue, even on a lightly used one that got stored away very quick by the looks, maybe a year light use tops as the lid is dark still. Always nice getting a 2020 as it's so big & classy in it's 1977 cool styling, put legs on it & call it a Coffee Table, after all it's on our Best Looking Amps page. But from having upgraded three of these over a few years it certainly does usually hide itself under the typical limited spec, though to a user just using one raw it still is Very Good or better, but they are still going to get the overheating failure. We'll try it on the Tannoy Golds later to see if it matches, hope it does & it does match very well. But... we've had the 2020 before & thought it was dull & muddy "soft" as noted above, but this one with little use isn't like this, on a second try after it woke up, treble is much crisper than a 2020 usually has & the thick bass isn't here. We've found before that Yamahas vary in sound on others of the same model. How Yamaha never noticed the overheating is remarkable though, the top regulators read a remarkable 83°C with the lid off & nearly 100°C with the lid on we read before. The extra kick of the 110w doesn't really make it much louder than an early 45w amp if it does it with more authority, this amp certainly has some kick once turned up a bit. Even after upgrading, it's a good but not perfect match to Tannoy Golds, bass & treble are Very Good but the midrange is just a little too forward. On Headphones, it has a punchy lively sound, the 100w gives it enough kick as well as having enough to fill out some hard guitar riffs. Still a more Domesticated sound compared to the CA-1010, but one that is listenable for hours without user fatigue, as usually later 1970s amps get for being too hard sounding. Sadly Hifi News doesn't review this amp, only the CR-620 & CA-810. These seem to have sold well & prices being offered at on ebay for ones untouched & still overheating can be unrealistic, but for a 1977 amp it's certainly the Best Receiver we've tried, with other brands using ICs in audio stages & cost cutting, the Yamaha still retain a quality, if by the CR-2040 range from 1980, they lose out for ICs to excess. ONE MORE... Got another one with the least use ever seen on one of these, for the usual aging seen, but even with probably a few months' use before shorting the outputs & having a joker fix it with not a TO3 but a TO264AA which is ridiculous & never worked so we can see one with such low use. Remarkable how a top amp like this would be treated this way, but thinkers aren't all of us. This one is still original. not recapped it beyond sorting the power supply. To hear as close to what it would have sounded like at the time, before it ages & the ceramics are noticeable. The sound is rich & full but treble is crisp & clean, we've heard more used ones sound muffly & a bit harsh, We actually played it after the 1984 Sansui in testing a few others but this is unusually good. Stereo is wide & detailed, not as dynamic as an upgraded amp but one we can enjoy. We've had a few CR-2020s & they all seem to sound different from dull & too rich to unexcitingly lifeless & edgy sounding as original. The serial number on this is high 2xxxx if others were 0xxxx series. Beware the current "internet misinformation" that the Power Switch "tends to fail" this is totally untrue on all those we've had. REVISITED 2018: We seem to get one of these a year, if with ebay overpricing & the amount of work in this amp to bring it up to our standard, it would be getting over 4-figures for us to sell on & that price does limit the market. The one we get Jan 2018 is a rarity, one owner since new, original box, lots of dust inside the open grille but non-smoker so the power amp wire cloth piping is bright white. This one needed the Power Supply rebuild, there is no way out of this & we expect there are loads of these amps sitting around not working for this. It needs our redesign & for the age of the amp it needs a full service too which is a big job as the whole fascia section needs taking apart. Once the PS rebuilt & amp serviced, to try a high grade little-used one is a rare chance. the customer didn't want the Power amp recapped which we see as a wasted opportunity as that brings a good improvement to the sound. On softer music the CR-2020 sounded pretty decent, a solid sound with a neutral quality, bass was acceptable if not to upgraded spec. But the treble on playing 80s rock & synth we found rather unpleasant, a splashy blurry grainy mess that lets this amp down heavily. Of course the CA-1010 sounds like this too, but flick on Class A, the CR-2020 doesn't have Class A, and the roughness disappears leading some to think Class A is better. But as the CA-800II & CA-1010 both upgraded reveal, Class A then makes no difference. The CR-2020 may sound acceptable on Loudspeakers that aren't too detailed, but on Headphones & our Tannoys it just doesn't please as original. Interesting to hear what Original High Grade amps sound like, but we'd not like to play it with the rough edgy treble. 2022 Update. Interestingly we get one that Sounds it's Usual Soft Blurry Sound but redoing the Power Supply brought a much better sound than we've heard on a 2020. Again the varying sound amid the production run. It's a UK 240v model. Sounds good on speakers, this one a clean smooth sound. Not the widest Stereo or Deepest Soundstage for the amount of Transistors the Signal goes through, if still one of The Best of It's Era. BUY-RAW RATING: Risky as power supply overheating will need repair with no exceptions, beyond that it's very reliable, but a big issue to overcome first. We see these making good money now as they deserve to, but yours won't last long as the design overheats on all. It'll start turning off on the relay & maybe won't start again.**We offer a power supply upgrade on this amp, our own proven design that keeps it reliable, see the Upgrades page. This is best done with a Service also for the age of the amp. COOL RATING: 8 more smart Yamaha looks, a big impressive amp & even better in the big USA style wood case. (2015-2018-2022)


1978 Luxman R-1040 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Very Good. 40w
FC, DIFF. Part of the Luxman 1977-78 receiver range L-1030, L-1040, L-1050, L-1070 & the earlier L-1120 of 30w to 120w. They done few receivers & the lower ones in this range seem to have sold fairly well so we get one to try, if 1978 is quite late, we've only had the L-100 100w amplifier above. The L-1040 was £330 in the 1980 so more than a similar 40w B+O or 38w Marantz. Inside the design is pleasingly different to the typical era with a unique heatsink & big gap in front of the power amp with boards on a beam chassis. Main caps 50v 10000µf is high for the era too. But being 1978 flashing red power output LEDs are a bit naff but Pioneer & others had this by 1980. It sounds controlled with a clean accuracy. No treble grain, certainly listenable with no 'eeks' on playing several tracks & after using & trying the next day it has woken up to sound even better. Power amp is a nice design with just 8 transistors. The looks are a bit busy looking with the LEDs always on. Oddly it has no Relay. The Power amp board has unused components spaces but no other amp or receiver uses them. Looking at other models to see Power Amp Transistor counts reveals the L-1050 has 10 with an extra differential pair & has a relay, the L-1070 needs 16 with 3 differentials, if the L-1120 only 12. The L-1040 therefore is potentially the sweetest sounding one, if all have a similar preamp. Preamp & Phono are 4 and 2 transistors each. This has enough quality to upgrade further than we went with it's tight clean but lively sound. Unlike the overdesigned 1975 L-100, this has similar qualities of finesse in sound if with a lively sound the L-100 couldn't give even after recap-upgrade. The volume on playing rock isn't as loud as others in the power range, but the sound is very clean, but as with the L-100, master volume is too soft on these amps. We altered ours to play louder (in a correct way) than the rather soft original volume & sold it like this. It sounded Very Good on the 1969 Tannoy Golds with the better volume upgrade. In comparing our part upgraded one to the 1969 KA-6000 & TK-140X this has a fairly similar smooth detailed sound which is unusual for a later era vintage, if it's not in the Yamaha CA-1010 league. But the low volume of the original will put many off, turning it past midway is wrong & then no more volume much past that. This sadly knocks our rating back as we try more differential amps. The amp can upgrade well, if not to the best. We found it a bit budget in several ways & to take the tuner window off to clean will try your patience. BUY-RAW RATING: Good. COOL RATING: 4 gaudy looks, annoying LED meters, naff rosewood & plasticky fascia, if very 1978 that will have high kitsch retro appeal as no other amp range looks like this, thankfully. But you may like it. (2014)


1978 Luxman R-1050 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: n/a. 50w
FC, DIFF. Details much as the R-1040 above. We have the rare "Luxman Lifestyle" version as a L&G R4000 which has a more classy fascia than the very 1978 looking original range, quite like a 1976 era Sony. But oddly it only has walnut effect vinyl wrap not the usual Rosewood veneer. It is the same power amp board as the R1050 & seems a much better made amp than the midprice R1040 for just the extra wattage, much heavier item & a less jokey looking heatsink, the preamp is one big board not two tiny ones. The extra weight is as the transformer unusually for a Luxman is multivoltage 100-120-220-240v & it has a relay unlike the R1040 which was £330 when the R1050 was £430. Getting this one working & serviced for a customer means we can rate it. It plays louder than the R1040 which was a bit feeble & the sound to most will be a lively punchy sound. But to us, it strongly lacks the finesse of amps from the earlier 1970s even as original, the sound is that typically thin underfed blurry & not too focussed sound, which is a shame. We didn't upgrade it but knowing how much the R1040 improves, if not to Yamaha qualities, there is potential in it. It still is made like a typical 1978-79 amp lacking the quality of earlier years as cost cutting was severe by now. On the basis of these two, Luxman seem very overrated & overpriced, the 1975 L-100 above wasn't too exciting & even the 1979 LX-33 valve amp below need a lot to bring the best out of them. But as there is a R1070 70w & R1120 120w the quality will be higher on the top models. BUY-RAW RATING: The one we had needed servicing to work even which is unusual, if beyond that the rest was good. COOL RATING: 5 the looks on this are much more mellow on the R4000 version than the UK R1050 but with only vinyl wrap it loses points, would be at least a 6 to 7 with veneer. (2015)


1978 Marantz 1072 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 36w
FC, DIFF. Continuing the 1977 range with a 36w model in the 1979 HFYB as £111 new. But it's a Far More Modern Build as we find out. One Marantz site says this is Rare, if by the Rack Mount handles, that version is, the standard front one is the one we have. Amp the usual width if depth less at 242mm compared to 300mm of the Marantz 1090, if will still fit in their standard wood case. By now Marantz were long into Comet so will be priced & built to a cost. Not doing too good with the 1152DC & 1122DC if the 2385 & 1090 were well behaved so try this. Decent grade one if missing control covers on the front if we have those, so worth getting. Seems the glue dried & they fell off, nobody thought to put them back on? Opening this one as typing to give opinions direct, the underneath Hardboard panel is a 1978-79 thing & it is what it is. Top lid the black vinyl effect with the grille over the right side only. Still lets the muck in, Attic dust in this case. One main board, finned heatsink with 4 transistors larger than the TO-220 type. Selectors use the more modern metal tape sliding way instead of bulky rotaries which makes the 1072 more sanely made, All those capacitors untidily fitted at an angle instead of neatly, we had a new c.2000 Rotel with the IC at a jaunty angle & soldered in barely fitting in, but that's Quality Control. 6800µf 50v main caps if no Relay. Needs a clean to look further. Uses the PCB mounted Phono input sockets as the 1978 Yamaha CR-2020 does, which came first? No Pre Out-Main In here. Phono 1&2, Tuner, Aux, Tape as Phono & DIN. Standard 1977 style speaker spring Push Buttons, Multivoltage, UK 800mA fuse is very low for 36w. Mains cable has an extended cable grip if it's not a plug. The build beyond the Harboard Base is a Standard used today even, no long wires makes building easier, some of the 1970s ones were so complex. The 1090 For Sale Currently & comparing both the 1072 is a tidier design & we like it better for that. Marantz are different every amp. The 25w Marantz 1050 looks much the same & is their lowest power model. Surprised to be Pleased with this, the 1090 not so well built but this in the '1980s' build style from 1978 without ICs is better than expected for it's level. The 1072 is 8kg, the 1090 only 7kg. Build is without the 1090 strange rods for button control, better ones fitted here. Underneath is the Hardboard with no Grounding Foil as it should really have. Just a few wires for HT, Shielded Cable to Balance & Volume, a short 'Computer' type cable Volume to Loudness, a wire duplicates the Track from the selector to the Preamp In, if twisted together not good. Tone has the Computer cable & Speakers selector runs front to back. No 'Old Fashioned' Hex Fascia screws on this one if still on the chassis & the 4 larger knobs are thinner made on the 1072. Construction hugely simplified here, does it mean Better Sound than the 1090 was as Raw? The Sound As Original. Needs Servicing first. Checked the Fuse, some idiot puts tin foil around the fuse. This makes it a 20A fuse or higher so ridiculous to do. Inside fuses are fine, they just plugged it in without even checking. 800mA fuse doesn't allow a Turn-On surge & aged amps can 'complain' on first turn on. But Serviced Up it plays Stereo fine. Sounds clean with Bass more obvious than the 1090. Modern Build with The Vintage Sound still. Why did it get abandoned? Sound is nice as Original, if thet probably bought a Flashing Lights CD system by about 1984. Shame it was put away if the CD era by 1983-84 forced the Plastic Horrors with all sorts of IC based junk. Plays Rock cleanly if lacking Bass weight, Stereo is fairly wide, has a punchy fast sound if does reveal it's limitations so might not have driven speakers too well, if on Headphones it certainly is better than expected & betters the 1090. Would rate it The Best Sounding Marantz as Original if just as by Headphones & we've had quite a few now. Circuits. A better .pdf scan is found online on the AK site. Aux to Selector, Balance & Volume, direct to the Preamp. Which of the 1050 or 1072 the circuits are is a mess, so compare to the blurry one. Phono is 3 transistors per channel inc a Buffer Stage. No Nasty Class B circuitry here. Preamp similar if what QN21-24 are for makes no sense, a Buffer in the Tone stage if no resistors? Power Amp is like the 4070 4ch one, it uses NFB around the Differential which gives it a 'nice sound' as we heard, a sort of 'T' Bass Filter too if not so honest sounding once realised. Could be dealt with by a bit of redesign if required. Board Layout is done well here & the PCB track is still thick, unlike hair-thin modern Tech. Output Transistors are 2SD718 & 2SB688 are early versions of ones still used & available, 80w, 120v & 8A suitable for 45w-50w amps. What a Step Up this 1072 amp is. What To Do With This. Initially just got it to use the 1122DC fittings as it looked worthy, if now seeing the Design & Build quality, this is a Rare Chance to find a Later Amp that could upgrade well just to see how amps past 1977 do. They've not pleased before, this one interested as you can read. We've really not tried any except the 1984 Sansui AU-G90X if that needed a huge amount done, it was for experimenting. This One Too? How Good Could it Sound? An Unknown here. Upgrade & Recap. Give it The Usual & see How It Sounds the only way. Then try it on Speakers to hear if it's As Good as the 1973 Marantz 4230 was in Bridged Mode, just done that early Dec. About 35 Electrolytics in this amp, the Quality from the Upgrade & tidying all the wonky capacitors, looks much better all in neatly renewed. Recapped Now. A few tracks to wake up the new caps. Betters the Marantz 1090 easily. 1980s looking build, if it's The First One so still has decent design if typical limiting. Bassy if Precise Sound for the Power Amp input stage, a little treble tamed but it Shouldn't Sound This Good. All on One Board beyond the Tone Sliders with passive components. All the Years we spent on 1980s amps looking like this Build, if with ICs & Op-Amps they never pleased. Yet this one sounds Great. Played Reggae so far, if now the Rock & copes well if brings out where it could upgrade further as Detail can be bettered & Treble is a little rolled off to sound tidy & be sellable at a price. A lot better than expected though. Imagine this sound in the Bigger Models, but it's overdesign there. Specs say 0.05% THD which is meaningless as Harmonics are way down unless the amp is poorly designed. Damping Factor of 45 is still 'Vintage'. This Amp certainly shows up most of post 1977 amps yet it's just another medium power Marantz as Sound Quality usually is better 40w or less. Rock needs more than this amp gives, if we're playing the same Tracks on many amps to hear what it lacks. Marantz 1072 for a midprice buy is impressive. BUY-RAW RATING: Good. COOL RATING: 6 smaller size as in usual width if less deep. (2020-21)


1978 Marantz 1050 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 25w
FC, DIFF. This is the 25w version of the Marantz 1072 above. They are Identical more or less beyond the HT Voltage & Power Output. This was a great buy at £84 in 1980. A standard Marantz width if ;less deep. Still a good design & Upgraded to a level to sell it sounds Clean & 25w outputs 22v Clean Sine. Seems we didn't note the 1072's rating though it could just be 25v for 36w, explaining why they are so similar designs. This one we got with it 'Not working' & finding some awful messing by an amateur, to the point anyone else would be annoyed at a bad buy, but skills don't come easy to sort it. The Power Amp worked, the Preamp was Faulty if they missed a certain thing plus messing with things some newbie errors, the LED they put in the wrong way & 'clouded' it. These Marantz deserve more respect, the 1050, 1072 & 1090 don't seem to have been sold to 'Hifi' buyers, more to Comet bargain hunters. All tidy & working now, the Sound is clean & smooth. Bass & Treble are more mannered, it could upgrade far more if not one we'd try fr ourselves & outprice it. To us, Treble Tone up a bit fits our Sound & it's still tidy on higher treble which isn't usual by 1978-80 era. To have bought 3 of these type of amps a case of bargains but also ones that are Worthy & to buy again if seen. The metal fascia still looks like earlier Marantz, the less deep case on the 1050 & 1072 would fit in a Marantz wood case to make it look classier & the extra depth of the wood case would still have it useable. Budget-Mid Price but still of a quality. "Not as good as the receivers" one said which is true, the pricing is very different, the Marantz 2226B in 1979 was £204 compared to just £84 on the 1050. Perhaps Marantz underpriced themselves on these & the later Marantz into the 1980s doesn't have the same Cred until the CD era mid 1980s 'PM' ones. BUY-RAW RATING: Good. COOL RATING: 6 smaller size as in usual width if less deep. (2024)


1978 NAD 3030 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: See Below. 30w
SC, DIFF. The Next Generation of NAD after the brief NAD 200 & 300 amp & receiver after the earlier NAD 160(a) & less convincing NAD 60 & 90 amplifiers. The NAD 160 was a good one as based on the earlier Sherwood S-7200 as we found & the amps were unrelated designs. So to try the NAD 3030, available in 'silver' initially if a black fascia shows it was around past 1980, if the HFYBs totally miss the brand by this time. These are Multivoltage if resoldering connectors is required on the 3030. Rear has all Phono inputs unlike some of the earlier NAD which had DIN only for some inputs, if DIN duplicates the Phono Tape Loop. Has the Marantz style bare wire spring sockets. Odd to not be Fully Complimentary by 1978. 6800µf 35v Nichicon Gold Print main caps suggests a certain quality & ours tested fine. Inside one main board with Input Selectors, Tone & the Power Amp & Power Supply with extra boards for Volume which is the Preamp-Tone stage & 2 small ones for phono as L+R on separate boards. No Bias Adjust if it's done by soldering in different resistors underneath which isn't user friendly when an adjust pot does better. The upright board to the left inside is the Meter board with adjust pots. From a look at the Circuits, no nasty Aux to Phono stuff here, all transistors if a few limiters as 30w would suggest but overall the circuit is a decent one & we'd expect it to have a fresh sound which would be untypical of later 1970s amps, which is good to see. But Servicing any amp will cost more than you'd get for it is the reality, so it's a gambler's game. sound is as expected, a fresh sound with very wide Stereo. But a slight hum on Headphones that'd barely sound on speakers, if we tried everything to sort that as stated below. This is much better sounding than the earlier NAD 60 & NAD 90 amplifiers. In terms of Rise Time, this as original is a Fast Sounding Amp, 15v/µsec is the spec which is unusually high, with Fast Recovery <1µsec so no sign of grainy treble played Flat. Bass even on a long-unused amp is decent, not as deep as a recap-upgrade but no limited ringing sound. No harsh sounds on dense midrange. Rock does better than many amps as original, if not quite having the weight it's uncluttered sounding if for 30w it's not bad. Overall a bit of a surprise for how '1960s' it sounds. Recapping this reveals the same sort of edge-soldered boards as Yamaha CR-2020 first used. The 2 small Phono boards are too small at 5cm square to have 5 transistors & 5 capacitors on, plus the other small caps. Difficulties in this amp are the awkward biasing system with soldering resistors not adjust pots. We done a lot to upgrade this, but we got caught out by the construction. Sadly it has unshielded cable for Audio inside, so it picks up a slight hum as played on speakers, it'd suit lower sensitivity smaller speakers & sound fine, but not 15" 95dB ones. On headphones the hum is more obvious. It is what it is, but instead of getting a nice price for it, to move it on to cover costs which is a pity. It's a Budget-Midprice amp & by 1978 things got cynical, we've seen unshielded audio cable in other amps. We try these amps just to see what they are about, if the post 1977 era can be unpredictable for the tight pricing & cost cutting. It does sound good, worthy of an 'Excellent' based on just the sound quality as upgraded, but the inside cables pick up Hum that is perhaps more hidden by the original design, so it's not rated higher. Later testing as Upgraded on our 15" Tannoys shows the amp matches very well & sounds great with deep bass. The Hum in daytime is barely audible, if on Headphones it is a bit much. To use like any amp & for late-night silent outside listening, the Mute button is there as designed to lose the Hum & up the Volume control a bit. The cost cutting of the era sadly, if we'd have expected better. to rewire all as shielded cable would be many hours work if it'd give a far better S:N ratio, ie losing the background noise. For the one main board with no ground shielding there is likely some Earthing issues in the design as wrong earthing brings hum in the most unexpected way. Because we can't get the expected price for this, we sold it off explaining the issues. You don't win them all in Hifi, if surprised at NAD, if maybe why it's not a known one. We'll look for HFN/RR reviews. BUY-RAW RATING: Good if top grille lets in all the dirt. Mains switch has a suppressor underneath that is likely to have failed so one to be cautious of if unchecked as it's right by the Headphone socket. COOL RATING: 6 pleasant enough if pretty generic looks if meters add interest. (2017)

1978 Pioneer SX-980 Receiver ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent 80w
FC, DIFF, Relay. The Last of The 'Monster Receivers' range by Pioneer as by 1980 the Marketplace was very different. The SX-1980 270w & SX-1080 120w were the two higher models. The 1975-76 SX-850 & SX-950 seem to have sold well if these 1978-1980 ones aren't so easily found. Since first getting a SX-950, we've found Pioneer are good designs but so heavily cost cut as Comet got hold of these, the Dec 1978 HFN/RR ad has SX-980 RRP £473, Comet £390 & SX-1080 RRP £555, Comet £450. Compared to similar, the Pioneer are much too cheap for similar Brands & Power, if prices are findable, eg a 52w Marantz 2252 RRP £495, Comet £365 shows you an 80w amp is probably underpriced by £100-£150, if here's where Pioneer cost cut to get big sales. Lid off, it's very different to the SX-950 & for a 1978 amp it's still impressive. it's Big.. 527mm wide, 175mm high, 390mm deep if 436mm deep inc fittings. Base lid off shows it's big for the sake of being big, like the Sansui G8700DB was, space to put about 1.5 house bricks under the tuner section. Front controls & boards similar to the SX-950. Huge transformer for an 80w amp. The fascia is quite like the SX-950 with a pleasing look with 4 black meters unlike the SX-950 & enough knobs & lever switches to look the part plus an odd tiny Balance one. Rear panel is typical if well laid out, 2x Phono if only 1x Aux, 2x Tape inc one DIN, Pre Out-Main In loop, AM Antenna & screw connectors for aerials, Multivoltage & Two speaker Pairs with push button bare wire holes that only take 2mm cable plus a 'Kettle' mains socket. The speaker connectors let it down, if all amps of this era are similar, but so far cost cutting isn't too obvious. Main caps are 18000uf 63v that are very high spec for the age. Improvement over the SX-950 is having the Power supply on the top to cool better, only the Relay is underneath. The lights section is a large perspex piece with 3 bulbs which are push-in blade types so unlikely any LED of that style & probably not easy to find replacements either. Power amps with an oversized if quite thin heatsink with L+R boards at either end looking very different to the SX-950. Build quality for a 1978-79 Monster receiver is better than the Sansui which had some poor ideas. Now for seeing where costs are cut.. The Phono stage sadly is an IC, for the huge space underneath this isn't good, the SX-950 was all transistors. Aux goes to the Flat amp after the switching sections with a FET into Tone with just 2 transistors per channel. Filter is a passive one unlike the messy ones some 1970s amps have with Filter amps. Protection by 1978 is more sophisticated with an IC, much like the 1984 Sansui AU-G90X has. Power amp is only 9 transistors, far better than some very overdesigned 70s amps. The output transistors are a new NEC type with 4 pins. 2SD 746 & 2SB 706 which are findable on ebay as of typing, Bipolar ones if not fully used as one pin isn't used. "200w Silicon Triple Diffused Transistor" if the datasheets are so blurry hard to tell what the extra pin is for. First Play of Sound Quality after a bit of a Service reveals it needs a full service, the sound is rather soft too. The stepped volume control as with the 1975 SA-9500 is a bit coarse, if to see what type it is once apart. Very quiet background, not totally silent especially using Treble tone shows it's not tamed too heavily like more modern amps that must have -120dB noise floor. Playing it a bit louder on Headphones, it has that 'flat' sort of low spec sound with a slightly Surreal Bass that does go deep if not totally convincingly & Treble-Upper Midrange a bit too edgy to please us, typical Pioneer sound & this is where the costs are cut. Bass sounds a little 'Retro' as not fully extended, it has some kick to it but the soundstage is very average, Stereo isn't too wide & depth is limited. On the usual Rock tracks the sound isn't very convincing, it's blurry, weight isn't solid & it all sounds a bit confused. No doubt as with Pioneer selling more to Rock buyers it'll get cranked up loud so it'll give the noise but not the quality, grimaces aplenty on playing Rock or high treble Ska & deciding it's best turned off as it's just too imprecise. Oh Pioneer... you make good amps with good designs but really crap out on the required spec to give good sound. But so do other 'Comet' brands. The 1973 range was first noticed with this sound as 1971-72 Comet got Pioneer. Looking on ebay, another one of these sold Feb 2018 for £785, the seller write-up shows we are on a different planet for describing sound quality... "The sound quality this machine delivers is absolutely sensational. It can handle an infinite range of music from jazz to rock and sounds exceptional with something a bit more laid back. The sound can be described as 'warm' and 'silky', Bass is handled with ease and the treble shimmers with such a perfect clarity." Well it shows from our Valves & Upgrading we are much higher up the Listening Ladder to tell what we hear it as. It's a huge learning curve & to most listeners, that description probably is what they'd think. Is an unserviced one worth that money? Would it upgrade well & be worth upgrading fully to see how good it is? Well we're recap-upgrading this one if not an extreme upgrade that we'd do if it was ours, so read on. It's a great looking amp, great facilities if only 1 Aux, but the sound is still that cost-cut Pioneer one. It's a big unit & needs a sideboard to sit on, no shelf unit here at 19kg. The Tuner picks up FM Stereo easily & a typical ICs one if it sounds lively if with the usual 'fizzy' sound on treble as all Tuners with ICs have. Why anyone would use muddy AM on a Receiver like this was at the time, many Stations were AM/MW only. On taking it apart to see the front panel boards, it appears a simplified version of earlier boards with not much on them, even the Power Amp boards appear sparse, not what you'd expect. The Volume Control is a proper stepped one like the SA-9500 uses, not just a rotary pot with indents. The Phono stage HA1457 IC, a 6 pin single-in-line type has an internal diagram in the manual, it's a complex if typical differentials & push-pull amplifying IC, if it contains 15 transistors & 8 resistors. But where is the Phono board in this huge amp? Tucked away on the Push Buttons right side panel meaning a lot to take apart. The rating as original taking in consideration what Servicing brings, we rate it rather low as you see, this may shock some, but it's the reality of the Pioneer cost cutting as well as aging of the amp. Mostly Recapped now except the Power supply, including Servicing at the same time, the Recap-Upgrade makes it sound a lot better. To re-read the initial opinion, the average soundstage & Stereo width is far better & bass is improved from the limited original sound. Rock is hugely improved from the disappointing original sound, the grimaces of before are gone on the testing session, it's not fully upgraded yet but it is far easier on the ears now. At last it delivers the sound it should, we were wondering seeing the boards & untidy wiring, but again the Pioneer cheaping out can be improved on. As with the 1975 Pioneer SA-9500, the first try mostly upgraded makes a huge difference. Playing more heavily Bassy tracks, it really doesn't have the weighty bass an 80w should be capable of, this is where we'll 'fine tune' the upgrade to give it a bit more, if it's possible to do within the job pricing. It's a fast sounding amp with strong dynamics, if not the weight & richness that other amps can do. At lower volume it still sounds a bit flat & cardboardy, if turned up louder you'll get more pleasure, explaining why Pioneer are more Rock amps than Classical-Jazz type. Phono Stage despite having ICs has a decent sound with a lively balance & sounds better than several other Transistor Phono stages. Now Finished to the Upgrade Level paid, the sound is a huge improvement over the weak & grainy original sound. Bass does go as Deep as you want, if further & complex upgrades which are actually our redesign would bring the sound out better. Is it worth spending more? Probably not for how hard the Power amp boards are to work on & surprisingly for the size of the amp, a lack of space to do it neatly. But to remember we are comparing to amps with a huge amount upgraded to look to see what this amp brings & to give the best upgrade for the money, some of the stuff we do is very time consuming to not bring enough difference for the cost it would add. To try the SX-980 on speakers, we've got the Sony TA-2000F-3200F much upgraded pair as the reference from listening just earlier. Here the SX-980 matches Tannoy Golds well giving an open & lively sound, perhaps better than the SA-9500 did. Handles a deep bassline from a TV show as good as any amp. The overall sound is surprisingly very like the Sony pair, if not the overall effortless & richness, but a very decent sound & remembering the slight mismatch with the SA-9500 it done better than expected. Therefore after a few more subtle upgrades, it does rate an 'Excellent' as upgraded, which is where we aim for in Upgrades, but it could do better if need a lot more work done. BUY-RAW RATING: Typical Pioneer cost cutting & needs a Service, if ours was little used. COOL RATING: 8 of the 1970s Monster Receivers that could get a bit too flashy, the SX-980 is purposeful & classy. (2018)

1978 Technics SU-C01, SE-C01 & SH-C01 preamp, amplifier & power supply set ↑
AS-ORIGINAL (Once Serviced): 110v version Recommended. 240v version is Too Dangerous. UPGRADED: n/a. 50w.
FC, DIFF. This is part of a very innovative micro Hifi system, 'The Concise', also you can get a ST-C 01 tuner, though a cassette deck would be too large at this time still & no CD yet. This is the Origins of all the cheap micro systems of today. 1980 HFYB lists SU-C01 preamp £153, SE-C01 50w power amp £296 though there are two versions of the SE-C01 power amp, the usual one has the external power supply & multivoltage. The rarer one-box SE-C01 is stereo amp or is bridgeable to a 100w monoblock, maybe it's 117v only as no room to fit the extra parts for the 240v in it. The size will surprise, it's about the size of a big UK city phone book, typically 297mm wide, 210mm deep & just 43mm high. So where does the transformer go? The preamp SU-C01-XN has a small one for just the preamp, but the one box or two box uses a switch mode power supply, again a design common in modern electronics. We looked at the Sony TA-F5A from 1980 that uses the same pulse supply though the rest of the amp was mediocre. The pre & power at £450 in 1980 is far from cheap as our Amps listing page shows. So what's the deal? Firstly, the power amps & power supplies don't age too good & we hear to find them not working sadly is the usual way, so this one needs repair before we can hear it play. The preamp, as are all the parts, is a heavy cast aluminium case like early CD players were, with the base lid removing. Construction of the preamp for it's size is excellent. Phono is MC with 4 transistors into MM stage with 6 transistors. Tone amp sadly is an IC as the Phono stages take up much space & isn't defeatable. Beyond the M5213L Tone IC full of the usual excesses, the rest is nicely made using typical quality controls of the era. The power amp of the two-box version is nearly half as a heatsink to fill it out. Only a meter range switch, headphone & the power output LEDs that are well graduated yet go to 160w on a 50w amp. The IC by the meter switch is for the relay & 2 ICs for the meter display control. The rest is all transistors again all is very neat with quality parts. The power supply box is the one with problems, so to take it apart & look. Nearly half is a metal can that hides the pulse power supply, the left is the power switch & voltage change with the power supply in the middle. Loads of screws undone later, looking inside the pulse supply. For the age & voltages here, to recap is a must. The one-box power amp we have here is a 100v Japan only version, and has a smaller pulse PS & caps as well as a bit cramped with two board layers & lots of wire. Similar to the 1979 Luxman LX33 valve amp, it has text on it telling you how good it is, the Power Amp has a graph on it showing THD... "This power amplifier is a "personal component" for audio enthusiasts, and incorporates the Technics' latest technology to make sound reproduction even better". The design of the 110v version of this amp is ahead of it's time but the 240v one has some very strange design features involving remarkable direct to mains connections, no way would that be allowed just a few years later. A case of being very clever in design but too clever to realise more obvious things just aren't so good or are reliable. Ideas actually used today with many non Hifi items not having mains transformers now. But as a design to make the tiniest Hifi system in 1978, it succeeds, but it is a bit insane on the design. The 117v version. On getting one of the one-box 100-117v ones working, the sound on just using the Soundcard volume is still the quality Retro sound with it needing a higher volume than some direct to Power Amp, so more gain will be in the preamp. The sound is balanced and detailed if nothing too special about it, if we'll run it in next. Now biased right the sound is much improved, the basic high quality sound if a lack of spec in the small case, it has a punchy sound it's not got the kick of similar 50w amps, but for a Lifestyle product as this would be today, be sure it sounds better than any of those things could dream of being, this is still proper Hifi, not just a gimmick item. The Power Amp by itself rates 'Very Good'. But there is a Preamp so it gets a try & the sound is not pleasing, much thinner sounding with bass almost absent, if the treble & mid are still much as before. Very Bass-light preamp therefore fairly knocks the rating, but it could be upgraded. The 240v version power amp-power supply we gave up on getting it working, as we'd not want to sell such a dangerous item. It uses 240v mains direct to a regulator, the relay & a big resistor. How it passed even 1978 safety standards is ridiculous, This sort of dangerous rubbish will have influenced early 1980s safety standards. These get a Review in 'Hifi News' in March 1980 together with other Micro systems. It says how hot the Technics gets, the 117v version runs pretty cool, but sadly they don't take it apart or even mention the insane power supply. But it getting too hot to touch explains why the old capacitors are so bad, as well as all being stacked so closely with little ventilation. Typically THD is mentioned but nothing about how Bass light it is or how it is a bit grainy too, to assume this sound was considered normal or the amps being new sound better than decades old. the only opinion is they sound harsh played loud if they read 60w, but having seen the basic power supply, the sound isn't surprising. **BUY-RAW RATING: 110v ONE BOX VERSION: This is still a risky amp working direct from 110v mains but is repairable without much bother as we found. 240v TWO BOX VERSION: AVOID Ridiculously High Risk & Unsafe, Lethal & Dangerous, if actually working. Live Mains goes direct to two points & must be put together to even try it as grounding is via casework, not wires. If this doesn't work, it can be considered too dangerous to try to fix even with a workbench isolator & we'd not be happy selling it so got rid. If it does work, get it recapped fast but be very careful of it for the 240v reasons. Uses high voltage capacitors that age like valve amps, really not recommended as it could be lethal. Do not buy this amp is our opinion. If-when it fails, it'll not go live, but just too risky in many ways. COOL RATING: 7 very cute tiny micro system, the purposeful yet miniaturization makes these a bit special as the first ones, need to be high grade though, but awful dangerous design is best avoided really. (2015)


1978 Technics SU-7100 amplifier ↑
AS-ORIGINAL (Once Serviced): Average. UPGRADED: n/a. 40w
Bottom of the range IC power amp, but not as bad as we expected, it's better than a lot of the sub £50 amps you see by the ton. Laughable hardboard base if the fascia looked more impressive. Still very much entry level to vintage hifi & not worth upgrading. This is what 10 years of progress does: 40w used to be a high power now the lowest one is 40w & made very averagely for the mass market to lap up. Sadly this cheap Hifi got worse as in 1979 so many identical looking gear of no real quality including from brands that had quality early on. To consider even buying this when the page is full of Very Good amps is a wasted effort, but it will still sound better than some £100 new amp off Amazon. Not worth upgrading a entry level model & finding higher models worth upgrading this late is not easy. BUY-RAW RATING: Good. COOL RATING: 6 smart silver fronted amp of plain but functional looks, with the tuner it looks rather appealing, unusual on base range gear to look like better quality. (2012)


1978 Leak 3200 receiver ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 25w
For a 25w amp this is surprisingly good if obviously power limited & sadly the last year of the popular Leak range, made in Japan by a non-brand company who manufactured Rotel & others but still a UK design with DIN sockets. All transistor era Leak we'd easily recommend except the early Stereo 30 with germaniums & the risks of the Delta 75. Phono stage is an IC which isn't Very Good, but of the era & price range. The 80w Leak 3900 is part of this range & we'd expect it to be decent too. Pre-out connectors mean you can use it as a preamp though the sound from the preamp is still kept modest in dynamics for the 25w rating. Still a semi-complimentary design showing Leak was using 1972 technology still as with the Leak 2000. But no Mono switch was a miserable omission. Not worth upgrading a entry level model & finding higher models worth upgrading this late is not easy. BUY-RAW RATING: Good. COOL RATING: 6 rather plain looking in the grey vinyl wrap case & the Leak wording a bit too big, a touch of the Yamahas here though. (2012)


1979 Consort CA 4000 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: n/a. 40w
Oddball amp UK brand made in Japan, looks budget goods but a pure lively enjoyable sound quality in a simple circuit that deserves it's ranking for it's good sound, copes well even with peaks tipping 80w on the meters, just limited by what you could upgrade into, a very rare amp though. Looks a bit empty inside with the main board facing down out of shame if it was all transistors & not much else beyond the basics. Not one we recapped, but it's sound was pleasing for what it was. Minuses are DIN connectors & an IC phono stage. We did contact the Consort guy who remembered it well but perhaps it was a costly failure & they never replied back, read on for why. We appreciated the amp though it's a bit too basic to be trying to upgrade it further, but we liked it in 2012 to rate it highly when we got Bang & Olufsen amps. The mystery of the Consort range unravelled further by a Jan 1980 HFN advert by Laskys, who we remember being in their Brent Cross branch as it closed in the very early 1980s. Their ad shows the CA4000 40w amplifier making the slider balance control a key feature, the Consort CT4000 analog tuner that boasted 'a Stereo beacon' & a Consort CD4000 cassette deck, as a job lot for £180 discounted from £200. Odd that CD meant 'Cassette Deck' for Marantz too, if not for long. The ad has similar midrange big name items totalling £300 so this was touted as budget-midprice, but as it was 1979 some sense of quality was there. These were exclusive to Laskys who were a big name in the 70s by their adverts but Consort never made this quality budget gear again, a pity as it bettered the Panasonic 1979 effort below. BUY-RAW RATING: Good. COOL RATING: 4 cheesy looks with a grey fascia a bit like later NAD, it looks budget gear if sounded Very Good for what it was. (2012)


1979 Harman-Kardon HK 560 receiver ↑
AS-ORIGINAL (Once Serviced): --. UPGRADED -- 40w.
Feeling the need by late 2023 to try more Later 1970s Amps & Receivers. From our 'Other amps' page & Blogs since, many post 1977 are Just Not For Us with ICs in the Preamp, Power Amp & Power Amp Output Blocks, much of which is Obsolete. The Build quality by 1979 gets a bit lacking compared to 1975 Hifi. Harman-Kardon didn't do much in the UK, we've only had the 1972 HK930 which wasn't the quality of one we had as long ago as 1992, a £20 Car Boot Buy in Our Early Hifi Days. This seems to have been the 40w Harman-Kardon 730 from 1976, the one with the Phono Board in the top at the back. One sold just the day before typing this as a Parts amp in USA for $300, seems just a typical aged one need of work rather than a wreck. if these 1970s H-K aren't easy to find. The HK560 ours is a 110v version, the 1979 version of the HK 730, there is a 220v version & UK HFYB lists this so a 240v version will exist too, all Rare though. To get one for a Cheap Price & see it needs New Outputs & the Power Supply Rebuilt at least gets one. It's like the Luxman LX33 below, 110v versions you can find, maybe a 220v but our 240v one is very rare. UK just didn't buy some brands. HK560 is a smart looking unit, better looks than the usual Samey 1979 ones. 425mm wide, 150mm tall & 320mm deep not including fittings. A 40w receiver with just One Windng for Audio & one for Bulbs, maybe another 240v TX could be fitted, if to use it on the usual Step Down TX unit. No Relays in this, but it does have Circuit Breaker Buttons like some other amps like Nikko use. Inside it's got a large tall heatsink with the MA-100 size Output Transistors, ones with a flange & £35 a set if you trust buying from China. We don't so will just fit some similar ones with a bit of minor alteration. Left unused most of it's life, someone badly tried to Repair it years ago, leaving no Output Transistors on the L channel & the Thermal Paste had gone hard. We find it Remarkable the Seller actually just Plugged It In on a suitable TX without seeing what's inside. One we'll fix up to get it going before any Recapping. It has a Version of the Dual Power Supply, one TX but Two Diode Sets to Two Pairs of Capacitors with the Complimentary Outputs. Harmon-Kardon post 1980 in the Black Cases are more findable, if they seem like most early-mid 1980s ones & likely lots of ICs. Circuits. Manual shows Circuit in Two Parts then in One Part below it, far more understandable in One Part p23/38. Phono all Transistors, the last two being that 'Class B' IC type design that was Standard by now. Preamp-Tone all Transistors, Tone after a Differential Input & a Bypass Option that's not Direct. Tone is the Passive Design with Ground References, not the Baxandall Circuit with NFB, which does give a certain Freshness to the Sound if done right. Voltage Regulator & what looks like a Buffer Output if this is for the Subsonic Low Bass Filter. Power Amp is the typical Differential with Balancing Adjust. Bias adjust too with some Circuitry to keep Impedance matched suggesting the Amp will be not the usual thin grainy 1979 amp. Inside shows the 1979 type build if better uality than some we've seen. Main Power Supply is the HK style Dual Power Supply for L+R Power Amps from one Transgormer winding, the other is for Bulbs. The 4 Main Capacitors look very small in the Case & other parts look a bit Modest, but this was The Trend by 1979. 4700µf 50v main caps is surprisingly low for 1979, if there are Two Power Supplies, one per Power Amp. The Preamp Voltages taken from the +B1 & -B1 HT supply when really they should have a Seperate TX winding to not Unbalance. This Cost Cutting again is typical 1979. Output Transistors are a 'M100' size like a TO220 with Side Flanges. To Buy One Set is £35 from China, we don't fancy trusting that or the price so will do it our way. The tall narrow heatsink does the job, we do prefer the TO3 earlier style transistors, the Original Ones to rely on Overpriced 'Maybe Originals' isn't what Hifi Rebuilding is about, to make it Future Proof makes more sense. Looks-Wise the Fascia shows more Style than the Generic 1979 look, Silver & Grey if Grey Print on Silver Brushed Aluminium not the most visible. Looks smart lit up with White light lines & the Mirror mid line. With Button lights too it does look smart, pity that HK didn't do more Higher Power ones, The HK670 is their highest power one then at 60w. HK670 has 16 power amp transistors of varied use, HK560 can get by on 12. HK670 on 10000µf Main Caps from Two TX Windings & uses TO3 outputs. Not much 40w to 60w in reality. HK560 on ±38v & HK670 on ±43v. The Reality Of Working On This. The Preamp is on a thin section of the large board right at the front by the controls. It's totally hidden by wires. The power amp stage is very small too & that was hard to get fingers into with the tall heatsink. To get to the Preamp board to need to take the Tuner Cord off & undo a lot of casework. Tuner Cords can drive you crazy for even following the loops it's never right & it's too cramped up. Ours a 110v one on a 1979 40w amp, it may sound decent, but ours still has 4v on the Speaker outputs, a fault that could be anywhere. If it's in the Preamp how can you test it easily with the Amp in bits. Sadly this one goes 'Unrepairable' a 110v one recapped won't do the £500-£600 price a 240v one should, it might do £450 or it could sit & only go for £300, making it not worth the job & the job it's already had. The last 110v amp we had was the smart KLH 27 & that only sold for a small & too-cheap price. Take It Apart Anyway. Just to see what needed doing. Tuner Cord off, all front panel parts off, unscrew the main board & leaving a loose mess. To know what to undo is The Guess & see what you break in trying. Really not worth bothering even if it was a UK 240v Mint one, it's clearly designed not to be repaired, which is early for 1979. Harman-Kardon can be seen as a Poor Brand for not even making it easily Serviced. The Preamp transistors were a bit hissy here so you need it apart. BUY-RAW RATING: If it works, just use it, it's not one to Rebuild. COOL RATING: 7 looks nice but zero cool for not being worth the huge job to rebuild or even repair the preamp. (2023-2024)


1979 Luxman LX33 Valve amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Very Good. UPGRADED rating is difficult, read on. 30w EL34 Valves.
See the end of the 'Valves' page & 'Other Amps' Luxman section for more on this amp. This is a 1979 30w EL34 Valve Amplifier, a more minimalist version of the SQ38 range that started in 1968 & had several versions by 1978 & was even revived in recent years. The LX33 is a version of the Luxkit A1033 without the option of switching output stage between triode & pentode. OY15-5KF output transformers appear the same as the earlier versions if only 8 ohms on the secondaries, earlier OY15-5 had 4, 6, 8, 10 & 16 ohm output options. The LX33 is a hefty 19kg amp with an open top grille that lets all the dust in but lets you see the valves if behind a regular amp type fascia with small light panels. We have one of these to service & upgrade to what we want it to be & are still altering things over 3 years later, so we can tell you our learned opinion: It's sadly just not 'very good' as the original design. The basic idea of the amp ticks many boxes as we list on the Valves page, but despite the hype written on the front, there is some very poor design in here from our knowledge of how it should be done & us re-building the TT amps below. On the good side it uses regular valves EL34, ECC83 on preamp & 2 of the power amp plus an ECC85 as the mid one. But the worst thing to us is the Heater circuits for the 7x ECC valves: it has AC heater on the mid power amp valve & an awful way of getting DC heaters for the other 6 valves, would you believe it uses the negative voltage Bias circuit daisy chained across 6 valves? The transformer hasn't enough current to do 12v regulated DC properly & space is tight to fit another TX. There is a remarkable spoiler in the circuit too. The speaker connectors are awful as per Luxman 1978-82 type ones, plastic head screw bare wire things that are usually chewed up as they don't tighten up well. The 3 valve shields on the preamp are actually for only the Matushita 1979 smaller glass case size so useless for modern valves. Pic online shows the first Phono one & last preamp one of the 4 plus the mid power amp side one have these. The sound as all original & serviced is very polite, limited, safe & just not very interesting if hints of valve quality, we can see why the one we saw got put in the loft for 30+ years. It sounds way too soft, like the 1978 Luxman R1040 but even less lively. The design is aged & lazy with tired old ideas accepted, very likely not much away from the 1968 SQ38 first 30w one, that never gets updated even seeing it in the 1993 Tube Technology amps. We're not here to massage egos after all. Our 1975 Luxman L-100 review above tells a similar tale, the sound just doesn't please. It makes us wonder how amps with this uninteresting sound get so hyped, but after all the Naim-Linn gear came shortly after. Knowing the better pre 1970 amps this falls way short of even a Rogers Cadet III for sound enjoyability. We find the other pre-power CL32-MQ3600 Luxman made was designed by Tim De P, a noted valve 'guru', but we've already said the circuit has some poor design in it, is it possible he designed it properly & Luxman dumbed it down? BUT... after all we did say this ticks a lot of boxes for Valve Amp Perfection & has a huge scope to be in a much higher league than the boring amp it was. If you buy this amp & use it as-is but serviced, you'll be disappointed in it is our opinion & it could be made hugely better, if the work involved to do it will be as involved at the 'famous' Trio WX400U we mention above. To the level we upgraded the one we had, it improved hugely, but needs full DC heaters & an advanced amount of redesign to be it's best. Sadly with valve amps, the designs are poor all too often, but the idea is to gut the thing out almost & rebuild it properly. Then it'll be much nearer how great valves can be. One for advanced buyers only. BUY-RAW RATING: Beyond deep servicing, re-valving & fools fiddling, it didn't have an Alps Blue as original, it should be good. Be aware most are Japan 110v versions, the 220v or 240v ones are elusive. COOL RATING: 8 the looks are unlike a usual valve amp, but it oozes class with the line of valves & big transformers, 19kg of amp here. (2015)


1979 Luxman L 2 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Very Good-Excellent. 33w. Looking very much like mid-late 1980s-today gear, this slimline minimalist Luxman looks pretty generic, but it has a decent weight 7.5kg & still all 'proper' hifi components, no ICs or double main capacitors in one can like a 1975 Sony one has. Getting the lid off is impossible, but to save you trashing yours, the top of the transformer at the rear right has a rubber foam pad that has stuck to the grille, so by loosening each hole the lid will slide off once unscrewed, if still far from easy as you'd expect & there are 4 rubber pads on the sides that will stick too. The inputs are strangely hidden underneath which may suit 1979 cables but thicker ones need taller feet by the pads a previous owner added, we put taller feet on & also the nasty Luxman plastic screw connectors are hopeless so to fit 4mm sockets can be done neatly. We have this one to recap-upgrade & to decide what is worth doing, if already knowing the lack of ICs which for the year & power is unusual. Power Amp board at the rear & one of those amps to take fully apart. Main caps are only 3300µf 50v which is Budget spec like an Eagle amp we got just for the Tx spares. As with the 1978 Luxman receivers, it's a strange built amp for where sections are put. On first play we are rather surprised how pathetic it sounds. On a positive side, it has a smooth sound that would Upgrade well so on that basis is Recommended, if needs a lot done to better it. But what we hear is a flat sounding boring no-bass amp. Very little to please here, no depth or 'friendliness' to the sound, it's Boring. Only just before trying it. we'd played some Vinyl on the... 1979 Luxman LX33 valves & that amp as original despite valves sounded as boring too. Once Recap-Upgraded it sounded a lot better but as a paid upgrade we didn't think it was quite good enough, so went back to do some more upgrades. This brought the sound quality into focus far better. Upgraded we rated it cautiously as on Reggae it could party along well for 33w if on Rock, the design couldn't quite deal with fast detail as well as other lower power amps can. 24v RMS clean Sine output puts it into 35w-40w league. On the Tannoys it matched pretty well, enough power to give a decent bass & treble was too. Not a perfect match as a little tubby in the upper bass but that's what 15" speakers will do, on 6" speakers that will likely fill out the sound better, as in speakers way outclassing the amp, but we like to try them all. BUY-RAW RATING: Good if getting the lid off is a struggle. COOL RATING: 5 actually looks very contempary to today's amps, rather plain but purposeful looking & not cheap looking for the tidy fascia print. (2018)


1979 Panasonic SU-2800 amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Hopeless. UPGRADED: n/a. 40w.
This & the matching Tuner was £20 delivered so a cruel try was worth a go. Budget IC power amp STK block thing that was true crappity crap budget gear, but it did have the 70s magic sound in there if you didn't expect much volume from it's 40w where it descended into quite awful fuzz of distortion on clipping. Worth a try to see what it was like & to sneer it & put a salty review online. It was mediocre. The 40w amp of 1979 is the low budget model, yet 12 years before 40w was high power. Reveals how cost cutting & giving more as lesser goods was the deal. This is utter junk. BUY-RAW RATING: Good. COOL RATING: 3 boring slimline looks that were common in 1980-82, even the tuner doesn't give it any appeal, but might do to those who remember it in the future. (2012)


1979 Sansui G-8700DB receiver ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 160w.
The largest amp for physical size we've had on our desk as of this 2017 reviews if we've had bigger Receivers since. Others were higher power & heavier, this is one of those Monster Receivers. 560mm wide, 203mm high & 475mm deep in total, just slightly less than the 35kg Pioneer SX-1980, if this is 21kg. Unusual for 1979 it has a Digital Display for the tuner, if still the analog tuner as the tuner pointer suggests. The fascia is very nice, classier than Pioneer or Rotel did, nearly symmetrical with Dolby FM decoder, much as the USA version of the Yamaha CR-2020 offers, but Dolby FM never happened if Wikipedia explains why this has Dolby FM. The lid has a sticker on saying 'simulated wood grain' if it looks very like the real Rosewood veneer Luxman used. The rear has the heatsinks for the 8 output transistors, if a little surprising to see a skinny 2 core mains cable on this. The side has a 120v sticker, if it's multivoltage. For UK use this really should have a more substantial 3 core mains, the 1975 Pioneer SA-9500 UK model used a thick 13A mains cable. The speaker connectors for 2 pairs again are a surprise, they are those awkward screw posts like the Luxman 1978-79 range had, even our LX33 valves had these. The idea of those was to use basic spade-fork connectors, but ones you see today have all metal cases & for the vagueness of how these connectors grip, you'll probably short the amp out using those & risk similar using bare wires too. Not ideal. It's good to keep original features, but when the original parts are not of a quality you'd expect, to make the amp more user friendly is an alteration that buyers & owners are happy to get. Be sure you'll find those who'll untidily cut a big hole for a kettle plug socket, only subtle suits our ideas as our Amps Gallery shows. The Inputs are on the right side panel, matching similar of the era that for some reason are able to be split into 2 parts. 2x Phono, 1x Aux & 2x Tape loops. This must have been a USA model as the 75ohm FM antenna is the bare coax cable screw & bracket type. Inside it's got the appeal of 'well made' like the 1973 Realistic STA-220 has. 133mm toroidal transformer, 12000µf 100v main caps. Power supply board not dissimiar to the Yamaha CR2020 in some ways, the other 2 boards are the Power Amps. The IC-looking thing is a double FET which is no problem. The large cast heatsink is like the 1971 Heathkit AR-1500, things like that show quality that is usually long gone by 1979. The big risk with these high power amps is who's fiddled with it before. Base cover off reveals a pre(amp) power supply & relay-protection board. At the front a decent sized Preamp board & the Dolby board. Powered on, a subtle warm lighting, unlike the garish Rotel range. Peak power meter is always on. The tuner display is only on when the tuner is used, so it'll not fade like VCRs did. We've been working on the Trio TK140X just earlier so have an 'ear reference'. Bearing in mind it's unserviced, the sound has some kick but not the most exciting sound if not particularly rough. The bass isn't too realistic with the design proving where, a tubby slightly 'retro' sound does seem unusual for a 160w amp. The soundstage, on tracks we just played earlier on the day of writing this now, has beyond the bass, a precision if it sounds very flat, as in the soundstage doesn't reveal the layers of sound & 'open out' as the 140X did. The sound overall is of quality, a service will improve it but for the huge amount to service in this, if it was ours, we'd recap & upgrade at the same time. Comparing to the 60w 1973 Realistic STA-220, ah... there's the nice open 'bouncy' sound again with much wider stereo & depth to the sound. What the G-8700DB would sound like with all our upgrades is a little hard to tell, the sound the STA-220 has is for the unusual design, here a busier amp can be limited in upgradeability. There is a slight background hiss on this that we'd not expect on a 1979 amp, without looking closer to see if some transistors are the cause, the STA-220 had the same issue. Back to the 8700 with a heavy bass Reggae track & this delivers a smaller more intimate sound with the lack of openness. To try the Joan Jett track we usually use for it's hard guitar, the 8700 delivers it with punch if the lack of bass weight shows & it's a bit edgy, the midrange isn't so precise. The STA-220 even lacking high spec new main caps does it far more convincingly. The obvious question by regular readers is how does it compare to the 1984 Sansui AU-G90X. The 90X has a very tight sound & we have upgraded the 'easy life' out of the 90X & it rightly stays as a reference. The Joan Jett rock track has huge ambience & accurate hard grunt that Rock guitar needs to not sound weak. The 8700 after hearing that as a reference again reveals the flatter soundstage, it has enough kick to fill the guitar well enough if the deep bass isn't there. Now after testing the subtle part of it, to crank it up for Rock, on headphones, the meters go to 1w power. Here it plays loud well, it comes alive with loud playing & most wouldn't miss the deep bass, but the above ideas of not having subtlety define true Hifi & the best can do subtle & kick hard too. The opinion of this amp, being a 160w one, is the design keeps on the right side of overdesign compared to some. We've written about Monster Amps before, this is a more sensible one, if that lack of sweet quality is with this, but if cranked up loud it sounds more together. It could upgrade well with redesign to give a more fresh deep sound, but that would certainly be a big job to do. It's a great amp for loud Rock, but it lacks the subtlety at lower volumes that we crave in the Quality & Detail so we're forever upgrading amps in search of it. We've tried to get the 1960s sweeter sound from the Yamaha CR-2020 before, got pretty close in some ways, but it just can't fully get there with a busy design. For an amp of this age, we recommend to at least get a full service & check, a lot to do in this, plus fit some better speaker connectors. To recap & upgrade would be great for us to try, but for a customer, it'll may outprice the amp compared to it's likely selling price, but if they want to use it regularly for years, then it keeps it in the best condition & gets it upgraded which will improve it's lower volume performance. The psueudo-stepped volume control notches are ok on headphones, but on speakers as always with any stepped control, it doesn't give enough precision. It puts out 52-53v clean sine, the exact figure is limited by the volume control notches. The 130w AU-G90X puts out 50v, so 30w extra only gives a modest extra. All serviced it sounds very noticeably better than the soft boring sound we found it comparing to other amps before servicing. The job of servicing is a complex one, but we're glad we didn't have to recap this as it is a much bigger & awkward job than expected, as is found with some amps. The construction for such a large amp is sadly that 1979 quality, for such a large amp the power amp boards are very cramped & offer little scope to upgrade, if we found that with the Sansui 5000X to a degree. How the previous owner managed to break the relays board is why amateurs shouldn't fiddle, if it was patched up. It's one you could use serviced for several more years, nothing noticeably problematic. Would we want to get one to fully upgrade? The sound certainly is much improved for servicing, there was a lot to do. To upgrade could be interesting as the basic quality is here, if for the huge amount of work compared to a likely sell price & for the huge size, too big to keep around, Other amps are fresher & more livelier, this is still a polite amp, yes at 160w, Stereo not especially wide. The design plays too safe. Tracks that the best upgraded amps make sound exciting are left not catching the interest, the Sansui AU-G90X has a very different sound to 1960s amps but once upgraded it does bring a smile, this leaves us wondering what's for dinner... Rock still needs playing louder than normal to reach a certain standard. Still with a proper 13A 3-core mains & losing those awful speaker connectors for some subtle 4mm sockets, makes it far more the beast it ought to be. On our Tannoys this actually sounds more impressive than other post 1972 amps. Midrange correct & Treble-Bass gain works well. The difference to an earlier amp tested straight after is noticeable for the 'proper' bass, depth of sound & much wider Stereo that the 8700DB seems not to bother itself with. After running it in for several hours, on speakers to try again. Matches well to early Tannoys, has a precision but again it sounds 'cardboardy' but it certainly could upgrade well. Having it on looking at it, the amp wants you to look with the lights & displays. For the buyer of an amp like this, they're buying it to crank up, for us who crave the finer details in music, this isn't really our sort of amp. It sounds best to us with Reggae as that's not densely produced, but give it something more complex in Rock or Soul & those deep layers are lacking. 'Very Good' if this is the sort of power you want, if try earlier amps for more musical value. BUY-RAW RATING: Good if not partied hard, be careful of ones others have fiddled with. COOL RATING: 7 smart & purposeful without going into the ugly side of Monster amps like Pioneer & Rotel. Very large size may put you off though. (2017)


1980 Pioneer SA-508 amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: n/a. 25w.
FC, DIFF. This is one of the 1979-80 fluroscan range & at 25w the lowest power model. Appears to have sold well & we got one someone found in the Bins behind Cash Converters when they first started. So that was over 20 years ago. It actually sounded quite decent & only had the volume control in need of the nut tightening. For the budget range it still sounded pretty good, the thing remembering back 20 years proving no IC block here but transistor outputs in all these, unlerss it was another model number? All these are pretty much the same at this budget level anyway so this stays if it's the only one not 100% sure of the model number. On using it the naff blue meters we found annoying & the graduation in power was next to useless. As it's Pioneer, the prices get overpriced but seem to have sold well. BUY-RAW RATING: Good. COOL RATING: 5 just average budget amp looks, the blue meters we find naff & unnecessary. (1992?)


1981 Sony STR-S5L receiver ↑
AS-ORIGINAL (Once Serviced): Average-Hopeless. UPGRADED: n/a. 40w.
It looked computery & the misleading 100w description on a 40w mass market average piece of junk, we wish we'd not bothered, average sound at best. LED volume is a cloth ribbon over a lightbulb. Piece of crap Sony as sadly much of their post 1972 stuff is beyond ones we note above & on the Other Amps page. One board type of amp not worth even thinking of upgrading or trying again. BUY-RAW RATING: Good if bulbs will need replacing. COOL RATING: 6 got this for the computery looks, but it's a bit of a crock & not what it seems. (2012)


1982 Luxman L-410 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 75w.
We know the earlier Luxman 1975-79 era in both valve & transistor, so to get this one in to service & upgrade after seeing it was a decent one is an interesting find. As most amps by this era are, it's a tin box if with a nice fascia with good sized rotary controls This one in Silver still, 75w weighing 13kg. The L-430 is a 105w version & L-510 is the 100w version, if in reality 25w extra won't make much difference, it is a bigger amp. Inside the 'advances' of the 1979 era in construction are obvious if when on it looks like an Xmas tree inside with several red LEDs glowing. This one has been recapped, if with a mix of cheap unbranded caps & some that are good, why use cheap stuff in a good amp? The layout will need working out if there is one op-amp on the front half for Phono plus 2 strip ICs. On the main board with the LEDs are more strip ICs, but these are just dual FETs on one package, no problem. The op-amp is a typical cheap-out of the era that nearly all 1980s-on amps have, no wonder CD sounded better. Whoever recapped this just done like-for like & the sound shows the amp is basically a quality one, but with the usual limits & low spec. Again, it does have the basics of a good amp. It really does seem that past 1980 only the amps at 75w or more have quality, if the sound was a bit weak on upper midrange-lower treble & deeper bass was filtered off as typical, but overall a better 1980s amp. Construction isn't quite as you'd hope compared to earlier ones, the weedy heatsink won't get hot if adjusted right, but if it gets problems with 13 transistors on it, not much cooling. The Phono stage ICs are disappointing on what would have been a higher midprice amp, maybe there were side wood cheeks for this as the slightly open fascia gap, but the manual shows it has small plastic edgings, probably removed for a 1982 cabinet. The rest seems good, several freestanding bigger transistors if the board track is still substantial unlike ones you see by 1984 when computer design could space tiny tracks very close. Now upgraded with our spec the amp is better than we'd expected for a decent midprice amp of the era. Sound is certainly improved from the 1978 range we've had as above, tight sound with a very solid bassline. Treble is a little soft compared to more open sounding earlier amps if it could upgrade further, it'll not bring much improvement. Soundstage is a little flat if the sound has speed & a punch to it. Stereo is adequate, the softer sound restricts it, if it's not grainy, it's just not as impressive as some. On Rock it fills the sound out better than a lot of post 1970 amps if plays safer in the freshness & dynamics, so lacks excitement. Phono stage with ICs is adequate if light on bass as is typical. But for a 1982 amp via Aux this is still one of the best ones we've heard, but to compare it to the late 1960s amps puts it in perspective. On vintage Tannoys for the upgraded amp, it matches very well on Bass & Midrange, but the weak treble lets it down. BUY-RAW RATING: Good overall. COOL RATING: 6 fairly standard looks if the big cast control knobs add to the appeal. (2017)


1984 Sansui AU-G90X amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent. 130w.
FC, Diff, FET, Direct Coupled, X-Balanced-Bridged. A very interesting later amp we got to try, but despite it initially appealing as quite different, it was soon found to be lacking a bit of quality as the spec is low to average in critical places, they didn't want you having it too good for sure. But we can upgrade after all... The only one of the AU-G range to have no ICs in the audio path, it is a bit of a gem for the era. The AU-G30X & AU-G90X predate the AU-G33-99X series which have ICs for tone & phono. But it does upgrade well & has a MC transformer, not the IC of the next range. Clearly the 'Audiophile' version & a hidden gem amid the IC riddled typical 1980s wasteland. It has separate power supplies for the L+R Power amp with a modest ±31v on the caps if with no ground reference & from the same transformer, but as it's got no ground reference in reality it sees 62v HT. Oddly the 45w Sansui 3000A from 1967 we have at ±39.1v, if in a different way. The technology is interesting: 'X-balanced' is based on studio amp's balanced transmission line design if no XLRs here, a Jan 1985 ad says "the input, output, power supply, drive circuit & even the NFB loop are all fully balanced" and "all parts of the amp operate independent of the ground" if it's clear we found the spec on certain areas is typically dumbed down so the hype of "the signal remains as pure as driven snow" is just a lie sadly, if it's in the amp before it was dumbed down to sell. The X-Balanced design once upgraded does reveal the technology is a worthy move-on from the best 1977 could offer, if typically 'domesticated'. All the AU-G series have this design if all, apart from the AU-G90X, have ICs in the pre-tone stage, which defeats the purpose surely. The Jan 1985 Sansui ad for the 90X says the Sansui B2101 & C2101 pre-power pair are this design also, see Other amps page as we have a closer look. On first play, it has a thin but punchy sound with a quality that is certainly different if a little dishonest in the upper bass from the spoilers & needing all 10 adjustments to be done right, else it will sound light on bass. If not all adjusted right, the Sansui has a dip in response at 125Hz to make the midrange sound more distinct. Only repeated tests reveal this, but we know how to test them to find out which is really the best amp. Putting a -4dB cut at 125Hz when playing the Yamaha CA-1010 regained that same tonal balance in the Sansui. The Sansui's low spec has a rather harsh edge to it with gritty sharp treble, losing the point of the advanced design, yet it gets THD & Intermodulation Distortion (IM) both rated at 0.003% showing how meaningless those ratings are if it sounds rough. Oddly the back speaker posts aren't real 4mm sockets, just an empty hole for the first 12mm of the 18mm deep hole, which is illogical, but that's the 1980s for you. Similarly, where is the Mono switch for Mono vinyl? The piano gloss plastic wrap wood effect edging is nicer than the AU-D11 II gaudy lid if the plasticky buttons are typical 1980s. But for a 1980s amp, it's revealed Good Ones do exist, if you need to look long to find another. Oddly has glass bulbs for the input selector, if LEDs on the other lights. To alter to LEDs need DC, the bulbs you can buy are white, too small & too bright. This has AC for the bulbs, so a little work needed to design for LEDs which we did. Almost the same as the Sansui AU-D11, Filters, Loudness, Phono switches, Input selector differ & the 90 has a nicer lid, if the AU-D11 II is just about the same if without the inside shielding. The later AU-G99X with the light meters & flat push buttons has some differences in sound balance from the circuits, the 90X seems more a purists amp if it still has Loudness. Some odd features are the huge 'toroidal' transformer looks like a regular one potted in a round can, but closer looking suggests the square bit is some sort of packing in the resin. 4x big power caps, 4 pairs of output transistors with a modest sized heatsink. These are like 4 separate amplifiers of 'Hot' and 'Cold' as there is no Ground reference for the X-Balanced design. The chipboard sides are part of the amp & oddly there is no metal casing to shield them. MC has a round can transformer, not the usual IC gain stage. PCB track is properly thick like 1970s if the track is a bit weak. The Schottky Dual Rectifier Diodes, D11 & D12, that look like TO-220 Transistors are CTP-2S & CTP-2R, not the manual typo. Unfindable specs, but similar type MBR20100CTP are 10A units. The Power amp circuit is one that initially appears overdesigned, 29 transistors per channel, 6 are output ones, but it does sound good which is rarely the case in ones we've tried, certainly would not dream of getting one otherwise without getting a try of it. The sound on this amp is very precise with huge dynamics, it could benefit from a little warmth & tidying some rough edges, but for what it sounds like, the depth of soundstage, does make this amp very special amid 1980s hifi, if there are certainly earlier ones to better it in terms of musicality. The Sansui just has that 1980s upper midrange harshness & that lack of 125Hz bass was noticeable, if it has deep bass kick if certainly lacking higher up. the low spec really does sound to us yet it does have a sound that is appealing if a little contrived for all the circuitry and/or low spec, if a better 1980s amp for sure, so Is this the Best 1980s amp we'll get? The AU-D11 Mk II is touted as the 'same amp' as the AU-G90X, but as always we can see it's nearly but not quite, Phono, Power Amp driver & others differ if power supply & Power Amp main board are the same codes. Biasing is tricky & the right order to do the 10 adjustments is: Preamp, Main amp, then the driver boards lower & upper pots which take many goes to get right & it may stay in protection until adjusted right. Of 1980s amps, it is unlikely there is much better than this, the cost cutting & basic construction beyond the boards at least gives an appealing amp still, if one that probably sounded way ahead when new compared to the usual 1980s grainy low-spec sound. The later AU-G77X has ICs in the preamp & phono stages, the lower models are a simpler design. Some needle meters would better the look, if the AUG-99X has big bar meters that fade like VCR displays, but it is a lesser beast in several ways: 99X has no case shielding inside, only 2 large power caps if 160w & extra space for the heatsink if a smaller transformer too. The 90X is the winner therefore. This amp does upgrade well to be the Best amp from 1978-date with ease, but as with all later amps, the amount to upgrade is huge. With other amps coming & going, this doesn't get played much, but when tests get serious, the accuracy of this amp puts the others aside, if the others weren't too imbalanced in tone to tune the hearing off, your hearing compensates like an EQ. It appears to sound dry & bass light compared to softer amps which it's not, it's just so precise & it certainly is musical with our upgrades which were difficult. In compares we have to use +2 on Bass but soon can do without it as it's 'sound' or precision comes through or the ears tune in. It can put valve amps aside for the knife-edge precision which is a little worrying. Trying this again after knowing the Akai AA-7000 & Nikko TRM-1200, the 90X still impresses. Certainly a different Bass to the earlier amps if very neutral & detailed. Amps like this can sound too thin compared to poorer designs that aren't neutral, but with a similar neutral amp the beauty of our upgraded amp is obvious & very musical to us more into 1965-67 amps & valves. A Reference Amp for us, all amps get compared to it now. The Tone gain is rated ±10dB but sounds more like ±5dB in use which limits it, if it can be altered. Phono Stage we've upgraded too, if it's certainly the best non-Valve one we've heard, very precise & detailed. Not good to miss a Mono switch if we've put Mono temporarily on the input to try vinyl, for the balanced design & Phono precision to Mono the input works fine. The AUG30X which is slightly later as it has no bulbs but LEDs puts Mono before the Filter stage. The Phono stage has differentials & Push-Pull that we'd run a mile from having heard many lousy ones, including 1977 Yamaha ones that aren't very good, but again the AUG90X changes opinions as they clearly done it properly, if the MM loading isn't quite right & it does show as a tiny bit edgy, later shows a slight midrange hardness, both we alter. A perfect Reference Amp for sure, if very hidden in the original spec, but always the way. BUY-RAW RATING: Needs a proper service to be it's best, cut-out issues can exist for aged parts & biasing is critical as well as complex-insane, as if some settings are too far out, it can have no bass & sound bright, or even won't start. COOL RATING: 7.5 big impressive amp, thick plastic covered side cheeks & all black fascia a bit hard to read & some plasticky buttons, but in terms of 80s amps it's got the look unlike the later AU-G99X. (2015-18)


1984 Sansui AU-G30X amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: n/a. 45w.
FC, Diff, FET, Direct Coupled, Semi Balanced. Part of the apparently rare but extremely good AU-G30X, AU-G50X & AU-G90X range so after the 90X being so good, got to try the smaller version. The 50X isn't even listed on some sites if the later 33X 55X etc range is far more findable, if these 1985 ones lose the quality for ICs in the preamp. The 30X has ICs for the MM-MC Phono stages but the rest is all transistors, only 2 bias adjusts unlike the 10 of the 90X. It's still the partly Balanced design in circuit but here the Speaker Ground is case ground. To hear how they compare is why we try it. On first seeing it, certainly of higher quality than the typical 1984 era amps, if plastic sides seem strange & the front buttons lack confidence. On first play it actually plays a bassline which is unlike other 1980s amps too. It's certainly not as clear as our upgraded 90X but the basic high resolution sound is here. Again one of those amps you wonder why it gets sold as it betters so many amps. There will be low spec in here holding it back as was the case with the 30X but this is a good amp for sure. It's quite weighty on guitar rock, certainly convincing if a blurry top as it typical with low spec. It certainly has some kick too, rather than softening the dynamics and stereo is wide. Compared to the 45w Marantz PM6002 from 2007 we had recently, even after the huge amount upgraded on it, this sounds far better even as original. A weighty 8kg for a post 1979 amp is unusual. On taking it apart to service, the front is held on with 4 plastic clips similar to the 30X tuner we have. A little disappointing no metal framework if many 1970s amps had wood lids with no metal so care needed in siting as hum may be picked up. The Phono board does have metal side shielding though. Different & better than the 90X the selector lights are LEDs & it has a Mono button, suggesting it came after the 90X. The sound of this as Serviced is way better than the rough sounding Technics & Yamaha below, this has quality & a proper musical sound with a bassline, very unusual for 1980s hifi in it's price range or higher. BUY-RAW RATING: The only issue is the Balance control wears on the track & can't be replaced, else good. COOL RATING: 5, just typical black plastic 1980s amp if not tacky looking as LEDS are subtle. (2015)


1984 Technics SU-V505 amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: n/a. 50w.
FC, no DIFF, computer control IC. Initially we found these interesting for the early Computer drive which was (allegedly) based on their hugely expensive SE-A1 & SU-A2 £10k pre-power combo. This was one of the Follies in Hifi putting expensive ideas done on the cheap into a Midprice amp housed in Budget grade casing. Look at the rubbish speaker connectors & thin metal lid. Heat pipe design unsurprisingly sounded rough beyond the apparent good idea. The sound was basically decent but so rough & thin sounding, but the one-board design is pretty un-upgradeable. We've looked again at this amp to see if it or the 707 are worth upgrading, 'Hell No' was the response, awful cheap one-board type of amp & the weak board track as was typical by now. BUY-RAW RATING: Poor as servicing needed else controls etc will be bad. COOL RATING: 5 typical post silver era looks, purposeful looking if the ones in silver add a point. (2012)


1984 Technics SU-V707 amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: n/a. 90w.
FC, no DIFF, computer control IC. Initially we found these interesting for the early Computer drive which was (allegedly) based on their hugely expensive SE-A1 & SU-A2 £10k pre-power combo. This was one of the Follies in Hifi putting expensive ideas done on the cheap into a Midprice amp housed in Budget grade casing. Look at the rubbish speaker connectors & thin metal lid. Heat pipe design unsurprisingly sounded rough beyond the apparent good idea. The sound was basically decent but so rough & thin sounding, but the one-board design is pretty un-upgradeable. It still sounds gritty at low volume & if turned up louder it sounds harsh. Perhaps the slow computer for bias adjustment is holding it back rather than improving it. If bulbs are dead the LEDs don't all work as we found out on our one, so 12v 55mA axial bulbs you'll need. On our one all we upgraded were the ceramics that tidied the sound a little, but with too much low spec when we looked again at this amp to see if it or the 707 are worth upgrading further, 'Hell No' was the response, awful cheap one-board type of amp & the weak board track as was typical by now. BUY-RAW RATING: Poor as servicing needed else controls etc will be bad. COOL RATING: 5 typical post silver era looks, purposeful looking if the ones in silver add a point. (2012)


1985 Dual CV 1460 amplifier ↑
AS-ORIGINAL (Once Serviced): Average (see text). UPGRADED: Very Good-Excellent. 80w-95w.
FC. Made in Japan to a Dual design. We've not really tried many amps past 1978 as the Amplifier & Receiver scene is rarely ones of High quality, the majority are Budget to Midprice & of no real interest to us. We get this one for a Customer to Recap & Upgrade, they prefer this on their Electrostatic Stax Headphones to earlier amps we've sold. They had this amp before, tried to recap it & ended up amp-less. We know Dual from the Clunky late 1960s Turntables & what appear to be Midprice amps through the 1960s-1970s as Dual were most popular in Germany & France, the owner of the amp is from France. The EU build on amps is dificult for the corner-cutting on build quality if not always circuitry, if this amp is obviously "Made In Japan" if under Dual Specifications says the rear panel. 95w RMS x2 or rate 80w x2 for 20Hz-20kHz suggests the frequency response is a bit tamed. The HFE manuals are too low quality to work from if the customer sends the printed original one save guessing what the blurry manual says. Not plugged it in yet, cleaned the dust out. First impressions are it's a better quality amp, huge transformer the same size as the Yamaha CR-2020, 63v 15000µf main caps are good spec. The whole front board has Power Supply inc main caps, Preamp-Tone & Power Amp as is typical of the era. Large heatsink in the middle with 2SA1106 & 2SC 2581 transistor pairs. Some larger transistors left without heatsinks if 2 have very small ones. On opening components weren't standing straight looking a bit untidy & possible to short the 4x TO220 size transistors if they bent over. Typical mid 1980s black standard capacitors like the 1986 Realistic STA2280 has. Audio cables are all shielded, the ribbon cable is for front LEDs so the amp is well made. The base cover undoes so no need to totally take the amp to pieces to recap as some by this date need. 230v version is fine for UK's 240v & other countries 220v, 2 core mains & 680w max VA power. Inputs are Phono Sockets for Phono, Tuner, Tape 2 & CD/Aux plus a DIN for Tape 1. MM/MC switch also. Speaker connectors are spring ones if stronger ones than some of the era. Plug it in, input LED lights if no meter bulbs. So far it's considered quite decent for the era, the needle meters on the front give it Bloke Appeal if it's still more on the Slimline size. Playing the usual Reggae test tracks we start testing amps with, it plays music if not with anything much more than just playing music. Not much bass, fairly clean & detailed if that typical blurry-grainy sound, not very exciting at all. Turning it up louder on headphones, it's quite restrained, the Headphone circuit is typical, so it just sounds rather flat, it has no real slam to it for 95w with volume at '4' it sounds like a 35w amp. Trying the Joan Jett Rock tracks, the intros on both her hits are thin & not to listen to further, it has no grunt or boogie to it. It plays detail reasonably well if it's very flat & lacking any hint of the 95w power. Suspect Current Limiting & Spec Limiting to a set price. What could be done with it based on our 1960s ideas needs the clearer circuits, if overall it's pretty much just what 1980s amps sound like & why the Music Scene of the mid 1980s was mostly lame as the amps had no balls. It's how we first heard CD in people's homes at the time playing it to impress us. The Circuits. We've now got a clearer schematic from doing our own scan so to trace a Line-Level input, the CD/Aux input isn't shown so must be a later version. Tuner, Tape 2 & 'Monitor' all go through a Circuit on the rear board with FETs, having a 22k or 47k resistor to Ground input, consider it the input Impedance, which is not a typical design, but it goes into FETs which is a Buffer Stage Input that on other amps doesn't really make them a better sound or worse. After switches signal goes to the Preamp which has Subsonic, another Buffer, Balance & Volume, then onto Differentials that have the Tone Stage amid with the Main Amp NFB output having the Tone stage in it, rather than a typical design if it adds a secondary NFB across that. It does work like any other Tone stage in use. Then onto TR9-11 which are the Power Amp Differentials with typical Bias & Protection. The power supply relies on Zener Diodes & is very minimal in design beyond that, just as 1980s-onward amps are. That thin boring sound appears to be from Limiters & Cost Cutting Spec. Whether it will sound good as Recap-Upgraded as the Customer asks is more certain it should do well, but generally it's impossible to tell what the results will be based on having tried over 180 amps on our pages. The 1984 Sansui AU-G90X upgraded well but it took a lot to bring it's best out if never matched our Tannoys. It started out sounding thin & hard to listen to, if with a basic clean sound that lacked the earlier amp's quality. Looking to Upgrade. Space is the problem here, for a start it has loads of ceramics & no space to fit in better ones which is difficult. The whole power amp pulls from the ±53v HT with only the differentials on a very low 7v. Very much typical of it's era as we've said, we'll do what we can with it, but to really expect better of an 80w amp leaves us sighing at it so far. Now All Recapped & Upgraded to the paid level. It initially doesn't sound very good, it's awful & not really that much better than the unimpressed review as original. We rated it "Average-Recommended". It sounded like an AM radio for how flat it was. Limited, blurry & no speed or kick to the amp. We were rather disappointed as the circuits suggested it'd sound good. To tell the customer it sounds lousy as a first opinion, but then to put it on run-in for several hours to waken the power supply & the 2 original capacitors up. To blame the Tone Stage as being weak, but it didn't make sense. But... the 1977 Rotel RX-1603 similarly sounded awful once finished, the long run-in & to find the main caps were aged, to replace & then find one was dried out inside. Now the Main Caps are replaced as with the RX1603 as they were bad & may not stay good for long, 33 years old now. Comparing to the Yamaha CR-200 15w receiver, the Dual isn't unlike that tonal balance if the CR-200 is more lively plus on headphones both amps play the same volume further suggesting the Tone stage in the power amp NFB is restricting this otherwise decent amp. On our Tannoys now it's trusted, it sounds repectable with a clean sound, wide stereo & a sound that we could listen to. Not as much Tone gain on the Tannoys as is typical of the Differential era if it does match well which is unusual for a 1985 amp. Puts out 38.6v RMS clean sine. On headphones it sounds decent, if still a little restrained. Interesting to hear another 1980s Transistor Amp which shows there are ones worth Upgrading. For a Midprice amp of it's era it does well, if we can still get better sound from the pre 1972 era amps. BUY-RAW RATING: Likely works fine for age once serviced & ours needed a good run in. Ours had bad main capacitors though & sounded terrible, see above. COOL RATING: 5 for the meters it has bloke appeal, if a plain metal case is generic by now. (2019)


1985 Yamaha A-720 amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good (in Class A mode). UPGRADED: n/a. 105w.
FC, 2x DIFF. The only 1980s amp (as of 2013) we'd heard that appeals, very good focus in the Class A mode if could be upgraded further, no ICs in main amp, just the phono. A one-board type amp that gets very hot in class A, heatsink a bit feeble as too thin. Only sounded it's best in Class A otherwise just a 'Recommended' score as it was quite rough. Needs servicing & a good run in else it sounded awful. Loudness control isn't what you'd expect it to be. There is a temptation for us to get this or the A-1020 to upgrade to see how good an 80s amp could be, but the one board design decides against as the very thin track is too risky. We've looked again at this amp to see if it is worth upgrading, the weak board track as was typical by now plus limited space in the layout & the feeble heatsink put us off. BUY-RAW RATING: Risky, needs good servicing else controls will not work right. COOL RATING: 5 average black fascia looks with lots of plastic buttons, nothing stylish here. (2012)


1986 Pioneer M90-C90 amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: n/a. 200w.
FC, multiple FET, multiple IC, multiple DT. This we had long ago as a repair, but the parts were unfindable so it got abandoned, but as typical they turn up on ebay eventually. But by then we hated the thing, it was rough condition & we couldn't care less so outed it as spares-repairs. The preamp was a disgrace, stuffed full of ICs & later versions had even more. A rat's nest of unshielded computer cable connectors all over the top of one big PCB with extra boards for power supply & phono. The phono was very overdesigned with loads of transistors then an IC probably for MC gain. It sounded flat & boring as we tried it with our valve amps, though it did have the Pioneer tidy midrange it was lousy. The power amp was a huge 20kg lump & looked the part with big bar meters at the front, with huge heatsinks & capacitors. Typical useless copper plated screws on a thin chassis that scratched the paint a bit easily & chipboard end cheeks that age badly. The power amp boards had a double FET package that was unfindable but then appeared on ebay as did the bias IC that we suspected was faulty & at least got rid of it, never to be seen again. But the power amp at least worked right on one channel so to rate it is possible. For 200w the volume was pathetic even using the preamp. This sort of high powered rubbish we noted as a poor volume with some Sumo amps, so we review those too. The rating of average is for the preamp, the power amp if working right was a much better item, but the low volume keeps it down. Preamp has loads of ICs for control, relays & audio mangling, if a transistor power supply. Power Amp has 3 differentials inc FETs, IC for biasing-switching circuit & 8 output transistors per channel 2SA1516 & 2SC3907 which at least aren't expensive to buy if damaged. BUY-RAW RATING: Beware obsolete PCB mounted parts if faulty. COOL RATING: 7 these have that 'High End' look with the power amp having subtle lit meters & plastic covered side cheeks, the flap once missing kills the looks, but as most 1980s things are, quality of a rough one shows how the veneer of class is a thin one. (2013)


1986 Realistic STA-2280 receiver ↑
AS-ORIGINAL (Once Serviced): Average. UPGRADED: Recommended. 60w.
We bought one new in 1987, but revisiting in 2012 & recapping to the max got a decent sound at lower volume but then but it sounded rough too early for 60w, for the sheer hell of it revealed how much ICs strangle the sound whatever you do, very restricted on bass on the original design. Unshielded audio wires in ribbons all over the place, nasty limited bass even with Loudness & the laughable IMX Stereo expander. The power supply was clearly low spec to sound so weak. Tuner was poor as digital but hold button type & memory battery long dead. Full of ceramics too. Almost impossible to get Stereo FM even at 5 bars signal as adjusting never worked. Budget cheapo stuff good for your first ever amp, but that's about it. As original, we'll stand by the poor rating. Upgraded it barely scrapes a Recommended but for the Stereo FM uselessness, it stays as it stands. BUY-RAW RATING: Good. COOL RATING: 6 very 1986 looking with plastic aplenty if the digital tuner & meter add retro appeal, after all we bought one when it was new. (2011)


1986 Sony TA-F550ES amplifier ↑
AS-ORIGINAL (Once Serviced): Average. UPGRADED: n/a. 90w.
FC, IC, DIFF. We got this in 2011 looking for a later Sony to see if it'd be good enough as a second amp for playing vinyl with, but it fell way short of what we expected... Certainly the most boring 'premium reference' amp we've ever heard, poor design STK block that runs hot for pre amp if transistor output stages. Phono stage is a Differential pair & an IC containing 14 transistors and a FET. Tone is Passive & the Preampincluding early Power Amp Stages is just the STK IC with 2 differentials & the usual junk. Here music sounds cold & awful as designed to kill any musicality: devoid of life, interest & not even a decent volume despite 90w. If this miserable sound is modern "hifi", then buyers are being conned or deserve to be. Rubbish sold as ES premium, oh dear. The only interesting thing with this amp was it has a piece of red velvet inside. The sound was so unappealing you'd reach to turn it off fast & this sort of crap is what mass market hifi is sounding like today. How Sony thought this miserable effort was acceptable just 18 years after the STR-6120 shows how far off the music dream 'hifi' became. This amp was bought to be just a Computer system amp as the TA-1150 we had tired of but it failed to deliver. But it got us trying the 18w Trio TK-150/KA-2002 amp & on noticing how nice it sounded, we went looking for more. The result you've been reading. There is no point us trying to upgrade amps with ICs or STK blocks, so we'll stand by our low rating. BUY-RAW RATING: Good. COOL RATING: 5 typical bland looks, better in lighter champagne than the grey-ish one, but as interesting to look at as to listen. (2011)


1990 Aura Evolution VA-100 amplifier ↑
AS-ORIGINAL (Once Serviced): Average-Recommended. UPGRADED: n/a. 70w(?).
We bought this from Cash Converters when they used to get better gear in around 1992, got our fax machine there too, the plug on this was sold as hardwired across the fuse so dangerous to sell, clearly untested. Silly chrome faced thing no tone controls, typical gold plated connectors but an IC on the preamp & probably Phono too meant it didn't last long as it wasn't very exciting listening. One big board & MOSFETS means just everyday audio gear of no real quality. Not rubbish but nothing special. Bought the E30 below after this. BUY-RAW RATING: Only known as nearly new. COOL RATING: 5 chrome fronted minimalist thing, can't hide averageness with a bit of chrome. (1992?)


1991 Sumo 'The Ten' power amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a. 100w.
These we had on demo taking them home before buying the TT valve amps. It may be from 1998 but we remember them & have a blurry photo. Huge rackmount black handled things with a big meter & 2 rocker switches. We assume they are "The Ten" 100w yes but not Class A as they didn't get hot. Cranked them up on the 200w 15" Fane speakers we used at the time & the meters hit 60w with ease but they weren't very loud, assume the matching preamp was a higher gain one. A clean sound was here, but so clean it was boring with the sound quality being rather soft without much kick or anything even natural sounding. Tried them for long enough to find them of no use. Perhaps the preamp for them would be a better match as they may need a higher input voltage to sing, no specs known. Next tried the TT valve amps & was much more pleased with those & bought. Both amps the shop was desperate to get rid of so they were going cheap, probably the shop system for early AV for a while. Oversized, boring & stupid is our unfortunate verdict of a Sumo amp & no doubt any of these huge amps that seem to be more a USA thing, but the sound being clean if boring means they deserve the rating for those into that sort of thing not having heard how lively earlier amps are. To us, they're not really Hifi in the same way the beauty of a 50w vintage amp can be. BUY-RAW RATING: Only known as ex-demo shop stock. COOL RATING: 6 big stupid but impressive looking things with huge meters, if you like women like that, this is the amp for you. (1998)


1992 Marantz PM-62 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Very Good. 60w.
FC, IC, DIFF, Darlington. We bought one new in 1993, revisiting in 2012 it wasn't a bad amp, but not a lively sound like pre 1979 as typical of the era so we upgraded it into a more 1970s sound. It has tone controls & phono, if they are via ICs that do limit the fidelity. Phono IC& Tone-Pre IC with differentials, current mirrors, cascade bootstrap, six foot long shoelaces, incontinent elephants etc, all designed to trip you up & crap on you. Once upgraded it was pretty decent in terms of early hifi testing, but not really comparable to the 1977 Marantz 2265B for sound as by 1992 a thin bass light sound was the normal as overdesign & ICs were the normal in the CD era. We did upgrade this to a certain level to make it sound less thin, but again the ICs & quite averageness of a 60w amp will never be beyond this & perhaps is the best we'll find with Post 1980 amps without going into the 'High Price' ones. BUY-RAW RATING: Good. COOL RATING: 5 plain black fascia looks to match the CD-52, just nothing special at all. (2012)


1993 Musical Fidelity Elektra E30 power amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a 100w.
We bought this new ex-demo probably in about 1995-96 & used it with a Marantz Receiver & then the Rogers Cadet III done as a preamp only. Crazy times but the E30 unlike the A308CR nasty thing below wasn't too bad but even at the time thought it was very ordinary & it probably had ICs too. It lasted a while until the TT valve amps arrived as it packed in for some reason never to sing again. Surprising to read it's 100w never thought it went very loud. The step up to the TT valve amps after this was quite a huge leap in sound quality. BUY-RAW RATING: Good. COOL RATING: 5 just a plain glossy fascia box with a button on, what's to get excited about. (1995?)


1993 Tube Technology *Valve* Genesis Monoblock power amplifiers, Prophet 2-box preamp & Seer Phono preamp ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Excellent 100w.
All valve. These we bought very cheap ex-demo in 1998 as they had been round all the shop's branches unwanted as the shop was quite a mainstream one into AV more than Hifi. We lapped them up & as the 2 preamps were so cheap bought the lot, much to the shop owner's delight. And ours. Despite temporarily selling them tired of the heat they put out in 2002 quickly bought another power amp pair back again not more than a few weeks later. They've got rebuilt now for the 3rd time & sound very clean, way ahead of the blurry sound we had thought was Very Good from previous upgrading. The original TT designs are very mediocre if they are attractive & well made. The circuits are very safe with what looks like just copying Mullard designs from the late 1950s with the valves running very cool especially on the preamps giving a boring sound. The Prophet pre unwisely uses regulated HT which we ripped out within a year of getting them & the improvement was very noticeable. As the TT amps go as all-original they are clean sounding if rather boring sounding, so to rate them modestly showing there is much potential is right. The price of the Genesis amps has kept quite steady over the years if way off the original selling price. Ones to buy to upgrade is the best recommendation. They do make a room very hot in the Summer as do all bigger valve amps is one minus. BUY-RAW RATING: Only had since ex-demo new, nothing really to go wrong. Beware these should have black fascia panels on the Genesis amps, we've seen several that take these off but lose originality. COOL RATING: 8 the power amps look very stylish if the black front panel others aren't so keen on, we had ours painted gold that looked far more classy, if back to black it fades away a bit. Preamp similar if just a closed box. (2000-2014)


1995 Sony TA-FA3ES amplifier ↑
AS-ORIGINAL (Once Serviced): Never Worked. UPGRADED: --. 70w.
MOSFET, DIFF, Mains Choke, Direct Coupled. Got one of these to Repair & Service, if you want to spend money on your amp to have it up to spec again it's usually a good one the owner liked, so don't be wary of trying us with your amps if you like them. With Sony we rate their 1960s amps highly if quality does vary over the years & the 1986 TA-F550ES we didn't like. This one in 1995 was in the pre-Internet era when CD players & even the "Tape" inputs say formats DAT (Digital audio Tape) & MD (Minidisc) both which showed promise but failed. "MOS exclusive design" says the front wording. The styling is pleasing with contours instead of square edges & has a Remote as was typical by now. Inside the open grille lets life in. Compared to the lousy 550ES this is far more sensible, large main caps 10000µf 56v, large MOSFET outputs on a copper sheet with a large finned heatsink. Toroidal transformer plus a smaller one which remarkably is a mains choke harking back to valve designs, you'd think they'd use a regulator, quirky. IC controlling means sealed relays for switching. Standard build quality by now means construction looks smart as did the 2007 Marantz PM6002 but the trouble is it's not substantial enough in places & why this one is in for repair. It's not been iopened since new, but if it had already been worked on, the risk of not being reliable is a problem & why electronics today are disposable. They don't make them like they used to. The speaker connectors are proper 4mm sockets unlike the 1984 Sansui AU-G90X, the typical way of putting stopper plugs but pry them out & there's a 4mm socket. Has MM & MC Phono if it looks a basic one as one IC op-amp & a few transistors. Tone is passive & comes after the Volume which isn't such a good idea as volume will vary it's quality. The User Experience with these Remote Control era amps will always suit the modern user, but the sound of later amps is rarely anywhere near the fresh sound of the earlier amps. How will this one do? Price when new was probably around £350 by the tone of other reviews, a modernised version of the 550ES say some but it's totally different. The mediocre looking Phono stage looks like an afterthought & to get you into Digital. Prices secondhand we saw one with no remote for just £80 which is amid general quality amp prices today, another with no remote made £170 in Germany but it'll still need what the one here needs to keep it reliable. Remotes are the problem, a piece of plastic handled & trod on for 20 years means many are gone, but the amp is still useable without, remotes generally for selector & motorized volume. But... this one as a repair was a failure & we did give the customer the option to quit or continue twice. Optimism helps get amps fixed if it's no guarantee & we even done some free fault finding to try to solve it. We get 90% success with amps, but the construction & design of this amp is awful, one fault brings another & this is the cynical junk of today. Later with another "non capacitor coupled" amp it becomes clear why so much trashed, the Built-In Obsolescence of these modern items to be sure once it fails you give up. They got 20 years use, lucky you. Now go buy a new one, even if it lasted 3 years. A cautionary tale on disposable later amps even if the were £400+ new: don't get involved if they don't work, despite being told "it mostly works". Even a 70w Sony amp from 1995 is disposable, we didn't like the 1986 Sony above but this looked more promising. BUY-RAW RATING: Looks decent, but bad construction with the supposedly better 'direct coupling' & design means if it stops working, get rid of it as it's a money pit. COOL RATING: None as it's generic. (2016)


1995 Spectral DMC-30 pre amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good (once Serviced). UPGRADED: n/a.
110v only. This is the matching Preamp to the below DMA-90 & we got this in late 2017 to service as the owner was having issues. To have both the earlier DMA-90 & the preamp will get this tested better. The preamp is 484mm wide x 104mm high x 320mm deep & is heavier than the power amp. Inputs are 6 line level with no Phono, Tone controls, Filters, if a Mono & Phase button as well as a Tape loop. Balance & Volume are via push buttons on the logic based boards. Inside under a heavy top lid, it's got loads of ICs, not what we expected, if no info found online to know what to expect. Relays, DIL switches & rotary pots to adjust an output volume. Inputs are Phono or XLR connectors, the front does say 'Studio Reference Preamplifier'. Build quality for this USA brand is top quality with one main board with control & inputs and one front board for button controls. The central preamp stages on a raised board. This has 12 of a 14 pin IC, the MPQ6700, MPQ6502 which are actually NPN-PNP 'complimentary pair' drivers in one package and MPQ 3904 which is 4 NPN transistors in one case. It saves space & there are benefits in having matched driver pairs, if the same thing could be done with regular transistors. Sadly these sort of amps have no Service Manuals, the idea is to return to the manufacturer which for heavy items UK to USA is going to cost. AFTER SERVICING & A LONG RUN-IN. The Sound from the Preamp is basically clean, detailed & accurate. It was rather dull & slow sounding before servicing. It does still need some Bass Gain on our soundcard to fill it out to match the 'sound balance' we are used to & a little 16kHz cut to tame the highest treble which is a little harsh. It plays Music well then with good detail, but it's not as good as the hype & buy-price suggests. The sort of amp that buyers of our Rebuilt Vintage are comparing to & finding ours is far more Musical, if not the same power, who actually needs over 100w? Trying Rock it just doesn't have the grunt to deliver guitar riffs, it sounds too thin if again EQ can better it. Not the fastest sounding amp therefore, the dynamics are a bit limited for what it claims to be, ie Studio Reference. Our newly arrived 30w 1978 NAD 3030 has better speed & dynamics on just a serviced amp. A natural compare of the Pre-Power pair is the 1984 Sansui AU-G90X. The sound then on headphones is like veil off & windows open, the Sansui shows the Spectral to be pretty average beyond it's detail resolving, the huge dynamics of our upgraded Sansui version are very different to the stock version. We found the Power Amp itself was better sounding than the preamp which sounds very Bass-light on other power amps. But It's Unrepairable. The Spectral offers no scope to upgrade or even repair for the computer board fine double sided track, we've tried to repair computer boards & 'no chance'. Some like these sort of amps based on Hifi Mag hype & Bought reputation, but now they're getting Aged, the reality is they are Disposable which for the Price Paid is insulting, but that's Today's tech. Always interesting to try though. BUY-RAW RATING: The preamp gets very hot inside, poor design & unventilated sealed unit. This is only obvious after longer use we noticed, life of certain capacitors will be limited. Direct Coupling can cause issues with the power amp reacting to an aging preamp for the excess heat by going unstable with rustling noises, if to try Pre & Power apart with Non-Direct-Coupled amps brings no noises & shows the Direct Coupling is the problem. Not Repairable for the double sided fine track. Very expensive for the problems. COOL RATING: 7 this looks very purposeful with all push buttons & a subtle LED display, high 'bloke appeal' with the power amp, minimalist if all very nicely made if not repairable for it. Pity no Phono or Tone for us Vintage fans. (2017)

1995 Spectral DMA-90 power amplifier ↑
AS-ORIGINAL (Once Serviced): Very Good. UPGRADED: Excellent** (biased to our spec). 100w.
FET, DIFF, 110v only. We got one of these to service-upgrade as it has issues, but certainly don't mind trying quality modern gear if cheap modern gear we'd not be bothered with. This is a USA stereo power amp of 100w in a slimline rackmount type case. It's 110v USA voltage only. Why it needs a 2MHz bandwith when most humans can't hear beyond 20Hz to 15kHz is a bit pointless, if a much argued point by others. The way we see it is why waste power amplifying RF & hash? Construction we saw was very impressive with much care in components, high quality sensible parts & few use the expensive silvered micas as the pillow-shaped brown parts are. 2SK135 & 2SJ50 output TO3s are 100w FETs, There is an op-amp looking device NPD5566 but it's a dual J-FET not an IC so is for the differential like the Sony STR-3650 first used in 1975, a two transistor package. Playing it direct from the soundcard via our headphone box it has a quality sound, clean treble, decent bass if a little soft in balance compared to the Trio WX400U valves & Heathkit AR1500 we played the night before. Some amps are loud enough with 20 on the soundcard, this needs 60+ for a volume suggesting the preamp will be a high gain & a 1.6v output pre is recommended in the user manual as are fussy ideas about 'high current preamps' which makes you buy their preamp too, right? The sound before servicing whilst decent doesn't really excite like the other two oldies, it's a bit restricted in the speed of the music so dynamics seem muted, hard transients don't fully extend as even a 22w JVC can, even using a different headphone box setting shows it's a bit limited & shows a lack of focus more as it plays louder. Nice clean bassline if edging on the tubby perhaps & midrange though, but we aren't using a preamp which is often limited. It claims to be 'ultra fast' but we hear a definite weakness in the lower treble to high treble as many amps have. But without a service manual what we'd upgrade will stay unknown. After servicing, the construction looks good but has some issues that lead things to come loose, such as loose screws & cables without much grip. Biasing is critical as once set right the sound hugely improves on the treble and makes a good listen unlike before when it was pretty average. As the Spectral hits the quality once biased to our spec which may not be the official one based on what it read originally, to rate it as 'upgraded' is possible if the rest is original. The Owner of this amp was delighted how much better it sounded with our 'upgrade' if it all adds to our knowledge of post 1979 amps that generally are pretty lousy, this amp shows there are still Great Amps out there which we like. The ** reveals a problem here. Spectral don't use serial numbers oddly, but on servicing, the one we liked has "Rev D" printed under the main amp board, the same owner monoblocked these so has two & the other one is a "Rev B" but with four soldered alterations which are updated as board track on the D, but there could be other differences too. First play of this serviced & adjusted exactly as the other one wasn't pleasing at all, thin & rough sounding. But on testing the output to test tones the treble rose to 15% higher than 30Hz to 1kHz suggesting an impedance change between versions. Together with the fact we only had the Power Amp not the Preamp sort of leaves us not knowing which version suits the preamp best & it may too come in differing versions. For the buyer new or as used to match the correct preamp to the power amp version could cause issues, you might get both 'bright' versions or both 'dull' leaving this a bit of a concern to match it correctly. The only test would be test tomes to read if the output is essentially flat the full range. But the owner of both of these using the preamp we've not had here yet says they both sound the same & as good as eachother. The preamp impedances will be why & it shows power amps do need the correct preamp, so we'll add this to our 'Buying Advice' page. See the above for the problems with these amps. BUY-RAW RATING: Keep it serviced, biased right & it'll be fine. COOL RATING: 5 just a plain slimline box with a huge rocker switch, minimalist if all very nicely made. With the preamp it's a better look overall. (2015-17)


2000 EAR Yoshino 8L6 *Valve* Amplifier ↑
AS-ORIGINAL (Once Serviced on Old Valves): Recommended -Very Good. UPGRADED plus New Valves: Very Good-Excellent. 50w. Class A PP Integrated EL34. A Valve Amp found online for £4800 as New for us to Service & Upgrade, we rise to the Owner's Challenge to sort some issues as this gets a chance to hear another Modern Valve Amplifier. This is an Integrated Amp as far as it has several Inputs and a Volume Control as well as you can use it as a Power amplifier with the "L In - R In" sockets. "PH" is Phono in, but from a separate Phono stage, there isn't one in the Amp, it's all Line Level. Unusually for a Modern amp, the Circuit Diagram is on HFE so we can understand this far better than the 2004 Prima Luna. EAR is a Tim De Paravicini design & his name was often mentioned in the 1990s Hifi News Mags & he appears to have started at Luxman around 1975 as those 'High End'-Expensive Transistor Preamp-Power amp M4000 200w power amp £850, M6000 300w power amp £1375 as in the 1977 HFYB. We have looked at the Preamp & didn't like all the Sound Shaping in the Circuitry & it was the Amp that started the 1977 Specs Wars. Firstly the amp looks great Chrome with Black Cages & Case all very much the look, if the central panel that reveals the board track when removed bleats "Technology At It's Best!" which does reek a bit as did the Luxman LX33 hype fascia & we found the LX33 design so 'good' we redesigned it to our ideas over 3 years. 4x EL34 output valves on each side in a line & the circuit reveals it's a Class A amp as there is no Splitter Stage if it is Push-Pull with NFB, not a SET-Single Ended Triode design as the market on those is a minimal one. The other smaller valves underneath are ECC83 & unusually the ECC85 which is otherwise long obsolete if the 1966 Sansui 500A valve receiver used '85s in the Tone Stage. Ours must be a later version as it has 330µf 400v main capacitors with 4 per channel. The ECC valves HT is taken from the main HT line via typical drop resistors. Class A means the Valves are always on, if still Push-Pull as the Transformer is wired like PP still. No Biasing apparently is needed as fixed Bias Voltage, but there is no Adjust Pot to allow for Valves which can age differently or any way to Balance the Valves except to Buy a Matched Quad per channel. A heavily burnt resistor on one board that had 2 valves replaced reveals this isn't a good idea, valves do need adjusting as they age, we used to check our TT Genesis amps every 6 months & they always had drifted as emissions weakened. Bias Too Low or Too High isn't good. The Yamaha Class A transistor stages, CR-1000 etc, took critical Biasing to stay in Class A & valves do drift over time when used. To get to the Valves is not user-friendly, the cage is screwed in from underneath & the thin PCB is on long stand-off posts that the screws appear to seize in for the heat. The top plate removes to reveal the PCB undeside & the main capacitor pins are very close to the case as the hole is too small, be sure the bolt added is glued in to raise the PCB away from shorting. PCB for EL34s we don't like as the track & solder ages as is noticeable here on the lead-free solder, if one goes open circuit you may trash a transformer. Power switch is recessed & a bit hard to switch on even with nimble tech fingers let alone sausage fingers. The original circuit design is scared of Bass as are most Valve amps, if there is no reason to, but it just hangs onto old 1950s-60s ideas that are never questioned like we do. The Circuit on the ECCs is rather odd & they're not Buffer Stages. The Output Transformer is the usual Ultralinear design, an easy design with NFB that loses the 'Classic' Valve Sound & we have changed our TT & LX33 to the far superior Triode mode after hearing how much nicer the Trio WX-400U design is, if it takes far better design to get to sound good. Class A Push-Pull is what the design is with a "lower NFB", if it has more NFB than our LX33. Surprisingly the ECC valves have AC heaters on the same TX tap as the EL34 heaters, the 1963 Trio WX-400U & 1963 Fisher X-100-B has DC heaters for small valves & design compromise to stop hum is the deal here. Until we get to hear the amp once a few things are tidied, we're sort of wondering what is with this amp & "... at it's Best" is not what we're seeing here in the circuitry, if the casework is. We're not going too deep into what could make this better & it's more precise problems, a commercial product still made New is Priced to The Market & the £4k-£5k price is where the idea of 'High End' starts. To assume the better design is reserved for the £20k amps, to make them seem worth the money. Cynical? Before getting the amp useable, the idea here from the design is the sound is Bass Light, rather Soft & lack of Depth to the sound for the strange ECCs design which could head it into the Prima Luna sound that we didn't like much, see the 2004 PL review below. The Amp Itself. There are changes on this version as noticed with the main caps & others elsewhere, so to work out what they are as board is numbered if the early circuit isn't. They've had feedback on what fails so Cathode resistors done differently with two as a safety feature. The Preamp stage differs more with slight improvements if still close to the 1950s-60s ideas. First Play Of It. Needed work to get it to where we're safe plugging it in. Not Recapped or Revalved yet. No sound? Only a tiny sound from Ground as the back small lever switch isn't to Lift Ground like the TT amps are, it switches Line-Selectors in to Power Amp input, it is marked on the mid plate if not which way to use. Sound has a bit of Retro Bass for the design, it sounds quite decent if playing louder it reveals the low spec, possible aged valves & sounds like a Used Transistor amp with that indistinct sound, lacking focus, if the more it gets played despite the slight hum it does improve so Class A takes a few minutes to reach the right temperature, the EL34 valves read around 150°C now. The Amp is now fast & does have some kick of Bass isn't what it could be, this is playing Reggae which is where we always start on Amp testing. Onto the Rock, it delivers the midrange accurately if it has really no weight to it, the sound is left thin with a slight brightness like the Rogers HG88 III & Cadet III have which is a pity as it's otherwise good. Temperature on the EL34s continues to rise after 15 mins use & the slight hum has faded. 1960s Ska the amp resolves the fast muddy detail well, if again the lack of a proper Bass does leave it lacking. Verdict as it stands is towards a Quality Sound spoiled by Weak bass. Compare to our Luxman LX33. Good to compare Our Design to an amp by a 'Valve Guru', but our 30w EL34 LX33 total rebuild, with Pentode mode not Ultra-Linear, easily betters the 6L8 from the first few notes. Playing the 60s Ska track, huge soundstage the 6L8 didn't have & Bass. Rock has the right Growl to upfront guitar. Stereo is wider & the dynamics are much bigger. To try the Reggae again, the LX33 really slams it where the 6L8 sounded a little vague. But the 6L8 is designed as a Domestic amp to play at home, our LX33 is unlimited like Pro Gear & having tried it on the Tannoys it would get you complaints as too big sounding. The Ultra Linear sound adds NFB giving that slight edge to the Treble, Pentode mode is more neutral & what the 1963 Trio WX-400U valve receiver has. Once you hear Pentode you'll never want UL again as it's too restrained. Back to The 6L8. On turn on a long 'boing' & the Hum again, needs Recapping & Revalving still. Let it warm up a bit first. The slamming dynamics are a lot less here if beyond the slight brightness the UL design brings, the Tonal Balance is similar. But to hear how it blurs midrange detail giving a bit of an edgy sound gets it sounding like the aged transistor amp again. So it's going to get Recapped & Revalved. This will tell the amp at it's best, if we're not redesigning anything or changing film capacitors, only the electrolytics. To try to even slightly improve the Bass resulted in Motorboating showing the design & transformers are lacking, our 100w TT could do 20Hz at high volume with no problem. To criticise is needed when a product is hyped by it's own name tag & for the 'Valve Guru' status the designer has, plus the high price of entry of one of these. With the Old Valves there still is a slight hum if with new PS Caps some rustling on the valves as well as the usual 'ping' noise from the valve reaching optimal temperature. The slight hum reduces as the valves warm up if it is heard on headphones, if on turning off the Hum goes. Recapped it still sounds much the same. So to now put the New Valves In shows how tired the old ones were, no Bias to adjust to tell bad valves here. It has the usual Hum on turn on but now no Hum once settled. Even before they get to the full Temperature they sound far better. The Tonal balance is richer with still good detail if Deep Bass isn't really heard. After more use no Hum or Noises, the background is very quiet. The Heat the 8 valves at Class A chucks out is quite something sat on the desk in front of us, nice on a Cold Day but in Summer it'll raise the Room Temperature quite a lot, even our LX33 in summer added 5 degrees C. The sound after 30 mins use shows midrange can still be a bit confused & the lack of Deep Bass or even Mid Bass leaves it a bit dry. Busy Ska is left a bit unresolved. Overall the Sound is clean, fast, somewhat punchy but still rather lacking to our tastes from our Valve amp exploits. Rock Guitar is a liitle soft, lacks the Punch & the blur of the Midrange really struggles. The amp suits less complex music better, but so does a cheap 10w amp... After over 30 Mins Use of the 6L8 Compare To The LX33. LX33: Much wider Stereo, knife-sharp focus, digs really into the Dense Ska Sound to resolve it to reveal the Room Acoustic. Proper Bass if not a Wallowy Bass like Valve Amps are supposedly said to be, that's an aged amp sound. The Ultra-Linear vs Pentode Sound is noticeably different with Pentode sounding more natural & open, the Ultralinear design by it's NFB is a more compressed sound. Much bigger Dynamic on the LX33 & can go very loud at 30w Push Pull Class AB. On Speakers using the Sony TA-2000F as a preamp to add Tone it sounds decent, quite upfront if again the Deep Bass does let it down a bit. Verdict on the EAR Yoshino 6L8 is it has enough of a taste of what valves can be, but design compromises, lack of bass & inability to upgrade the Bass leave it pretty much in the league of the Prima Luna amp reviewed below. Sorry Tim, but we both know it's not really "Technology At It's Best". Prices as used on a £4800 buy new are £2200 with three of them on Hifishark site from Italy at €2600 which as a used amp is still holding the price, but it's the same one on 3 sites. Whether any are selling is unknown, not seling is the idea. They are very specialist amps after all & the Heat is what got a customer soon selling a similar Class A EL34 amp. How to tell if a valve is aged is impossible here, no adjustments or test points beyond taking apart make this amp in the 'could do better' range. Our Rating of VG-EX is for the lack of bass, if Bass was better it would scrape an EX, if not a high EX. BUY-RAW RATING: Needs Regular Maintenance. 1999 amp needs valves replacing regularly if used often. Power Supply has weaknesses, cage fitted solid isn't user-friendly & the poor PCB posts will cause bother. COOL RATING: 6 as Modern Valve Amps go it's as good as you'll get so an "8" if -2 for the self-congratulatory & not really true 'Best' wording which is not cool. (2018)


2002 Arcam FMJ C-30 preamplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: n/a.
IC, Surface Mount. We got an ex-demo one to possibly use with the Musical Fidelity A308CR power amp after tiring of their preamp. The thing was very user-unfriendly to use with buttons to press to access features, clearly the designers never bothered to use it. So naturally it got opened up. The Phono board was a traditional components type board & actually was as good as our valve Phono at the time. But the main PCB was the awful surface mount "technology" with ceramic chip capacitors & other modern IC junk that is not hifi. The Tone has ±12db gain as it is microprocessor controlled but it did little on the speakers. All a waste of money but buying at ex-demo price to sell on was easy enough. To recommend a very awkward to use preamp with ceramic surface mount tech compared to "proper" hifi of earlier years is tricky, but if you are only after modern gear this is probably very much what the buyer unaware of earlier Hifi would be happy with & get little enjoyment from it too. BUY-RAW RATING: Only had new ex demo. COOL RATING: 6 purposeful for the era, silver front & LED displays but fussy to use (2003)


2002 Musical Fidelity A308CR big pre/power amp combo ↑
AS-ORIGINAL (Once Serviced): Average. UPGRADED: n/a. 250w.
FC, IC, DIFF. We needed to rewrite this Amp review as it was based on opinions from 2002, and since finding our Speaker mismatch theory, we've thought more on this, if not tried one again, but you can't hide a lousy amp. We got the big pre & power amp of the A308CR, model numbers used on an integrated amp too confusingly. It was bought ex-demo on a whim, tired of the heat the valve amps made in Summer. A bad idea indeed, but at a giveaway ex-demo price we managed to get out of ok with ebay. Huge metal casing & cast bits to impress visually, but the inside was miserable & looked like an empty box for most of it, very average spec. The Phono stage on this "High End" thing was a sodding 75p Op-Amp. Everything was just so Ordinary Quality with cheap Ceramic capacitors & a whole lot of circuitry that we found was killing the sound. In fact we used these on either the 250w 15" Fanes or the Tannoy Golds & the sound was just so boring. the amp had no Tone Controls & the Golds do need a bit of Tone we notice on testing later amps. But even then, the Bass was very artificial, it seemed the excess NFB lost bass so they put a circuit to put Bass baclk, sadly no circuits are findable. It actually gave us a Headache & we don't get Headaches unless a bit dehydrated. But the 308 gave headaches each time it was used so it had to go & the TT valve amps bought back again remarkably a few weeks later, if not the same ones. There may be a chance of mismatch on the Power amp, but we did try it with the Valve Preamp with Tone & it still sounded so unappealing. The Damping Factor gives away the high NFB at 180, when Vintage amps are usually 40 to 60. Because Hifi Reviewers aren't as honest as we are, Payola, oversized overpriced merde like this still sells well to those affected with gullibility... Our rating is considered fairly for the false sound it delivers. Ah but the case looks nice which is more important to these MFs. Musical Fidelity are modern mass market crap cleverly sold via Hifi Mag hype to those poor souls in search of Good hifi. Go buy a cheap Leak 30 or 70 & then tell us it doesn't sound more pleasing than just about ANY post 1980 amp. Overall we just didn't like the very average quality of the circuits beyond the flashy outer case work, money spent on casing not in proportion to the electronics inside. BUY-RAW RATING: Only had it when new. COOL RATING: 5 again big stupid oversized fakery like the Sumo, it'll appeal to a certain crowd, but to us they are a bit naff for spending so much on the oversized cases but little on the circuitry. (2002)


2004 Prima Luna ProLogue 2 *Valve* amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended-Very Good. UPGRADED: Very Good. 40w.
One we got to upgrade & repair so a chance to try a Modern Valve amp that we'd not otherwise get to try. The PLP2 is KT88 40w valve amp with selector & Volume control, a passive preamp therefore. The build as others say is excellent with experienced builders here (in China) if the brand is in The Netherlands. KT88 valves are the ones Reggae Sound systems used to use as a PP pair can put out 100w. The sell price of this amp for the construction is great value, but be sure corners are cut in the circuitry & overall spec, which is more important. It has an autobias circuit that is useful for valve newbies, but overall we prefer to set it ourselves. We get the idea the autobias tries to cover some design weaknesses on the cheap but does it successfully enough. Stick with the PrimaLuna valves, they are much better than "Upgrades" using rubbish valves like the JAN ones. First try, using those "upgraded" valves reveals a lively upfront sound with enough attitude to impress on first listen, but to us we soon find noticeable weaknesses in the sound. Power supply spec is low spec for a start & it becomes harsh quite easily, making Rock especially a hard listen as it runs out of power. The spec is decent in places, but where it matters the sound is left wanting & we soon turned it off, rather than play a few hours like amps we like get. Later using the original PL valves the sound is much more pleasant, if still revealing weaknesses. One stage is a lazy cheapout that others have copied for over 50 years, but it loses a lot of the fidelity. No circuits findable on this, but we found it has AC heaters on the 4 front valves so any upgrading may reveal heater hum, though the design has no noise beyond typical valve noise on Headphones. The trouble with the passive preamp going straight to the power amp is that volume has to be high enough & most amps are with a preamp give a higher signal voltage. Here they just drive the valves a bit excessively creating the hard sound that we still found tiring after upgrading some. But we are listening to Hifi we upgrade to our own non-conformist standard based on Valves & PA quality so know the weaknesses in this amp & tried to overcome some without getting into issues. But for the price these are New or Used on ebay, they are Very Good value. No Phono, except a miserable op-amp IC add on, No Tone, No Headphone, No Mono & No filters may put some off, but if you can live with that this is a Very Good starter amp into valves. On speakers the sound was impressive,, but a bit of a hard edge to the midrange being unbalanced stood out more than via Headphones, but still good enough to rate Excellent. We tried it as a Power Amp using our valve pre with Tone, but this just accented the peaky midrange. For the price, it's a Very Good starter valve amp, easier than the 1960s ones whivh need work done, but soon you'll tire of it's lack of finesse, though our upgrades did improve it quite noticeably, but if deep pockets allow it'll still have impressed to make you want to buy a 'proper' valve amp with the expected features, instead of this basic gear. This was an interesting amp & be sure it's way better quality than the odd Chinese brand ones. It looks best with both cages off, if that reveals some finish issues. Just a shame they have to cost cut the circuitry and spec & skimp on not having a better preamp when we can see they know how do it better than this. But the price is the attraction. There is good upgrade potential in the amp is our opinion after having upgraded the one we had in, but not really worth going too far. Free upgrade hint: ditch the ECC82 (12AU7) for ECC81 (12AT7) as the sound is much sweeter. BUY-RAW RATING: Good. No need to revalve usually. COOL RATING: 6 appealing in a minimalist valve amp way, but looked better with the cases off. (2014)


2007 Marantz PM6002 amplifier ↑
AS-ORIGINAL (Once Serviced): Recommended. UPGRADED: Very Good. 45w.
FC, multiple IC & multiple DIFF. Because it was cheap & looked nice, the temptation to see what a 2007 amp by one of the Top 1970s Brands was too good to miss. First of the PM6000s range that currently is at PM6005. All are 45w amps if mostly black fascia & later ones with a DAC. "Proper" looking on the inside with Toroidal transformer, heatsink, power caps, output transistors. Nicely made in Silver if like a DVD player & no duff capacitors as 2007 often had, Marantz used quality parts. Finally get it working, the sound is competent but very tamed, treble a bit bright & deep bass limited, but most vintage amps after 1967 are low on deep bass too. Not a rough miserable sound though & to be fair as a first play we've heard many vintage amps sound much worse though they suffer from age & being unserviced. On trying Rock it sounds a bit thin without the kick it needs & focus is a bit unsure sounding. Surprisingly they still use messy glue to stop the big caps falling out, vintage amps without the glue coped well so why glue here? We tried it on the 1969 Tannoy Golds expecting a mismatch, but not so. The Tone + to - test showed a noticeable change if not a perfect match. Stereo was wide but overall the limited sound became boring for the deep bass limiting giving a one-note bass & lack of fuller dynamics. But to be fair, on Speakers way beyond it's usual partnering, this amp didn't disgrace itself at all. The Phono stage is cleaner than the awful IC Phono stages of old if soft on detail. The omission of a Mono button is a pity & no Pre Out-In sockets. Source Direct gives buyers the idea it's Amp Input to Volume to Power Amp, how naive. It just bypasses the Tone stage but nothing else. This was a Five Star 'What Hifi' Amp (as most are...) when new. The current PM6005 has no ICs in Audio & adds Digital inputs, but it will be as 'sound mangled' as this one is despite the sales hype. But Marantz still make Turntables. The PM6004 & 6005 hype about no ICs with transistors allowing more design ability, well that's what we said on an early "We Hate ICs" page (now Valves -ICs page) 'An IC is just a general purpose design'. Did they read our page & use our reasoning? The Cold Hard fact is Marantz sales hype gives the impression they are improving all the time, which is not true. After making Transistor amps since the late 1960s you'd think they'd sell better goods than how unappealing the PM6002 sounds raw. We upgraded ours & it improved a lot but still not better than the 2265B we upgraded as noted above, but to score it 'Very Good' is fair, but hardly worth the effort, we just done ours for the hell of trying. Progress in analog audio is a myth. We had a look at the PM6005 current model, it just adds a DAC to the PM6004 & also the higher model PM8004 just has too much additional circuitry to not sound as good as the PM6002 upgraded did. We did upgrade the PM6002 doing 120 changes as so much is dumbed down, but ultimately the fragile build quality is not repair-upgrade friendly to sell it on which confirms how disposable modern electronics are. There is a reason the PM6005 is only £299 new, it's just going to be e-waste in a few years, just like every mass-market cheaply made amp made since about 1982 is. Shocking. See the 'ICs Are Not Hifi' page for more. BUY-RAW RATING: Good but beware Volume control issues. COOL RATING: 6 basic but smart silver fascia for modern life, but otherwise just a plain tin box. (2014)


*PHOTO GALLERY
We've added many pages of photos of the actual amps we had & were taken as they were sold. An unique archive of Serviced, Cleaned & sometimes Upgraded amps with many photos inside & out.


*MORE AMP REVIEWS
See the "Other Amps" page for others we looked at but didn't like or try yet for various reasons, plenty of amps there get a look.