Home  
  Vintage Hi-Fi Blog

• Hifi Home Page •   • Hifi For Sale •   • Quality Hifi Upgrades •

All contents of this Website are Copyright. Original research, photos of our hifi & all unquoted text is ©2011-2022 by select45rpm. This is all published freely on the internet by us to further the scene, not to give any seller or forum 'expert' undeserved credibility. We Do Not Authorise any Copying, Republishing or Quoting, even as rewriting Our Research In Your Words, of using or linking to any of our Sections on ebay, any sales sites or anywhere else. No-one else has formed these opinions, so don't steal them as yours. Please do not link to our site on ebay sales trying to use our unique info to play buyers for a sale suggesting we are authorising their sale, as we are not.

  • Search For Hifi info 
 


Hi-Fi Blog... Page 3 - 2019

See the MAIN PAGE for the INDEX.


January 2019 Blog

So What Do We See as the Vintage Hi-Fi Scene into 2019?
Interest in Vintage Hifi is very strong, in it's own still quite small market, as with anything Vintage that takes effort to discover it's worth over New. Amps that wouldn't have sold for £200 as 'raw' amps 5-6 years ago now regularly sell. The buyer is still getting a 40+ year old amp, we wonder what they do with it, appears if it works they just use it sounding aged & tired, so miss out on How Good It Could Be. Ebay is stuffed full of Overpriced Amplifiers that are usually the Good Ones but way outpriced, look at the Glut of Yamaha CA-1000 & Marantz 2385 ones at prices far too high, yet they don't sell as they are 40-45 years old still. We have both here as of typing to have noticed the very high pricing, a CA-1000 should cost you about £300-£400 & a Marantz 2385 is about £1200-£1400. Our Pages get a Lot Of Hits as people are after opinions & info, plenty of Info sites like HFE (Hifi Engine) & Elektrotanya for Free Manuals, some for General Info on what there is such as the long running McIntosh & Marantz sites, but still very little Opinion based on knowing many amps beyond the Newbie Forums that can mislead. The Hifi Mag sites review Vintage & get it quite wrong, just digging out an aged amp & accepting this as how the amp is. This year is 2019 so your 1979 amp is now Forty Years Old. The scene of £1000+ amps has eased off, you still see very plain Modern Amps at £5000+ but they never sell. The Wise Buyer is realising you don't need 300w & that lower power amps 20w-50w are all you really need with the best ones having a great Musical Sound unlike the overdesigned ones. The Modern Valve scene is still hyped as "The Best" if ones we've heard reveal dumbed-down designs if the looks & "Lifestyle" of a Valve amp is the selling point, the mess a EAR Yoshino Class A amp was after some years use & owner fiddling shows these amps need maintenance. Servicing Hifi is rarely done, we only get Recap-Upgrade-Restorations that can cover Repairs, no-one wants to pay to Service an amp, if just doing the Service can bring a muddy Monster Receiver back to life as with the 185w Marantz 2385. More are realising a Rebuild is what their amp needs as the amps we cover are at least 40 yearsa old now, if really who else but us is offering this with Upgrades based on Redesign, so it's still a niche market if those getting Rebuilt amps can often be mindblown by the improvement as the Rogers HG88 III rebuild we did just recently. To us, it's just doing it properly if that has taken over 200 amps to get right & be sure still more to learn. It's getting people Listening to Music, To Rediscover the Music that meant a lot more 20-30 years ago but have sort of forgotten it as later 'Stereos' don't give the Musical Pleasure. Good Hifi can make you a lot happier. It's not cheap to get it done right, but buy carefully, get it rebuilt & listen to a 1965-1977 amp like it's new again, with a fresher more lively sound for the upgrades. To try the Scene, go buy a late 1970s Amp or Receiver on ebay for £50-£100 by a named brand & get a taste of The Sound You Miss.

Addicted To The Upgraded Sound?
We still try to play Amps as Original on Speakers, once Serviced, to hear what the Buyer 'Back in the Day' would have heard, we tried with Pioneer & Sansui amps as blogged a few months back. To hear the 'good' in the sound but feel frustrated by the limited sound of the Spec of the day, the lack of preciseness in Treble plus the typical Weak Bass even with some amps having harsh Bass Filters that really smear the lower frequencies. To us it's good to hear as Original to listen for what is good & what clearly needs to be better. We have Customers who buy multiple amps, they soon realise the Tonal Balance of each amp will differ somehow. It depends what Speakers they use & we keep going on about Tannoys which has made 1967-74 Golds & 1975-80 HPDs get very expensive, if you'll never regret buying them. One was finding the sound 'harsh', to suspect lesser speakers weren't bringing the best out, they decide to try some ebay 'raw' amps, a 1968 JVC amp they found sounded clean if it was noisy in use & had poor bass, then to buy a 1977 Trio-Kenwood amp of about 30w a midprice amp but just found the sound weak in general. They had sold us some amps & had got 2 great 1960s ones if still found they sounded 'harsh' which from knowing these 1966 Fisher 600-T & Akai AA-7000 they were very smooth sounding amps on our Tannoys. They're suffering from Bad Speakers, the 3-way type that pretend 3 drivers is better but the Midrange driver needs a complex crossover that actually ruins the sound by giving poor midrange rather than better. But after the customer tried the 'Raw' amps they realised the 'Upgraded' sound with proper bass & clean detail put the other two amps away as 'no-good' because they knew the better sound & have decided to get some Tannoys. We started Upgrading Amps years back to try to better the sound, to search for 'Perfect Sound' yet we can still find another amp that sounds better still. The amp we've had on speakers over Xmas was the 1965 Sansui TR-707A, all recapped it sounds wonderful, if the background hiss from the Germaniums can get a bit wearying, the TR-707A just sounds so right in every other way. To hear that 'sound' and try to get similar in another amp is the challenge. So far, several amps can tick 8 or 9 boxes out of 10, but never be the Perfect Ten.


Rarely Seen: Amplifier With Separate Transformer Windings Pre-Power.
This is far from the normal design. Many amps just use one Transformer Winding plus Big Resistors or Regulators if also the lazy designs get the Zener Diodes. Having a separate Preamp power supply does appear to have benefits without lossy stages. A Receiver often will have a separate winding for the Tuner stage, the Sony STR-6120 has this & many others do too. But here An Amplifier with more than one TX winding is rare. To look at some Amplifier Favourites to see they use One TX winding for the whole power supply, not including a winding for Bulb stages: Sony TA-1120 (A), Sony TA-1140 uses one with a variant, Sony TA-1150 uses dropper resistors from the main HT supplies. Akai AA5000 has one if uses half wave rectifying to get 2 supplies from it. Dokorder 8060, Ferrograph amp, Hitachi IA 1000, JVC MCA 104E, Leak 30/70 amps, Pioneer SA-900, Rotel RA-810, Sansui AU-666, Teac AS-100, Trio-Kenwood KA-6000, Trio-Kenwood KA-8004 others. Two Or More Windings: Sony TA-1130 uses three in a strange 'add-on voltage' type design as does the TA-3200F power amp. Akai AA-5800 has two. Luxman L-100 has three. Marantz 1152DC has three if we've not traced to see if one is for bulbs. Marantz 1030 two plus a bulbs one. Pioneer SA-9500 Mk I two, Sansui AU-999 two, Trio-Kenwood KA-6004, Yamaha CA-1000 & CA-1010 have three. Does It Make any Difference? Yes, any amp with separate windings or even earlier ones with two Half -Wave Rectified supplies from one winding have better detail as the Preamp & Power amp don't both pull from the same Power Supply at the same time. But Not Always. Some of the earlier Amps that use Dropper Resistors that get hot can still sound great. The Multiple Transformer windings on later 1970s amps will have a benefit compared to others of the era as cost cutting became such an issue. But the fact a complex Transformer is expensive, this is why they are rarely seen. It's an interesting Design Feature if probably only more noticeable 'as Original' on the 1970s-1980s amps.


Battle Of The 1966 Akai AA-5000S vs. AA-7000.
Both here Dec 2018, both recapped with upgrades. AA-5000S is still half Germaniums, they give a very smooth sound at the expense of background noise. The AA-7000 is all Silicon transistors but for the large size of the amp the long wires inside still pick up hum so it's not really that much quieter & for the design still based on Germaniums there oddly is a similar background Hiss even with quite a few New Transistors fitted. Not for everyone then on either, but the Music is what this Compare is about. The AA-5000 has NFB in the preamp so has a punchier sound, the AA-7000 with NFB opn the power amp on first hear sounds deceptively softer, but to get into the sound it's understood. AA-5000 played Rock well, the AA-7000 is a little softer if is a more open sound, after all we did use our first one on speakers daily for a few months. The AA-5000 is more precise, the AA-7000 isn't as focussed in the midrange as playing Rock revealed. Back to the AA-5000 it has a slight hum too, if not as much as the AA-7000 always had. The AA-5000 is more precise though if not as bassy so to see why & alter. The AA-5000 with the Preamp & Power Amp on separate boards all with shielded cable gives very wide stereo. Just about every amplifier has the Preamp stages L+R on one board sharing ground & power supplies. The rather modest-looking inside AA-5000 needs some upgrades to get the best sound plus the awful 'bloop' on turn-off needs redesign & to wonder why they did it like that. AA-5000 tried on speakers, we had a AA-7000 only returned to the customer a week before which we thought sounded great. The AA-5000 still does sound great, the Germaniums that are still in the AA-5000 S don't hiss much as the design is quite tailored to give a good sound which to our ears does lack a certain freshness. It's not one we'd play but one we had to try. The AA-5000(S) is a smaller item than the AA-7000 receiver & both are High Rating on Retro Cool Styling.


We're Forever Being Asked About Upgrading Budget-Midprice Gear.
We get messages asking if 'xyz' amp is worth upgrading. We could tell you 'yes' & take your money knowing that it's Money Not Well Spent, but that's not our idea of Uprading amps & it'd frustrate having to try to get quality from What Wasn't There to start with, we've found that with some 1980s amps. Average amps are Not Worth The Effort To Upgrade, we've tried enough of our own to realise. To think to Spend £300 minimum on a Recap-Upgrade & much more on More Complex amps, to tell the Potential Customer there amp isn't worth the effort wastes their time as it does ours Researching said amp. The Best Results are from Upgrading 1965-1977 era Amps that were High or Middle Range models. The 1973 Yamaha CR-1000 is the top one, the CR-800 the second one still worthwhile, the 18w CR-400 is actually better than what Sony did at the same time so it is worth upgrading & we've got a second one here to work on as we thought it was a good amp. But the Tons of 1979-1998 type amps are a different thing, big sellers like NAD & Audiolab etc are just Low Priced Amps as 'Richer Sounds' & 'What Hi-Fi' used to Rave about. But to us who from this site you can see we know a huge amount of Vintage Amps, over 180 are Reviewed, we see these really aren't worth spending Upgrade Money on. Ones we've tried we thought they were a bit crappy & were glad to get them out of the way, together with feeling like it was a waste of time as you can't really get past a budget design. A Good Straightforward Design can give good improvements, but Cost Cut designs with poor construction & known failure issues really do head into Disposable as are the Glut of Not-Working AV-Amps on ebay, they are e-waste. Good amps are never e-waste, they can be forever repaired or wanted for parts, but Average Amps are just £50-£100 budget buys. If yours stops working, go buy something similar as often lightly used ones get sold on. It's not worth Recapping or Upgrading by us, you can try to do it yourself & learn some skills, but again look on ebay at the Recapped Amps with no inside photos showing work, why are they selling it? Because it didn't sound any better. Some of these Budget-Midprice amps that are still considered 'good' today, to us are awful amps & ones we'd not want as Freebies as we couldn't be bothered putting a Good Upgrade into an amp that will not give good results.


Hifi Time Travelling: 1985 Dual CV-1460 As Original On Loudspeakers.
To hear what these Amplifiers sounded like at the time, as near as can be. Unlikely a Dual CV-1460 95w amp from 1985 has ever been played on Tannoy Golds perhaps, but if you bought it once having moved to Europe where these were a popular brand in France & Germany, to hear what they'd hear. Our Review of the amp tells we find it rather average sounding just like any other cost-cut 1980s amp if overall it shows upgrade worth & a customer is getting theirs Recapped & Upgraded. So to hear what it sounds like. But it appears we can't easily test this amp either, read on. But we do as the last comment says below by using 2 plugs, which is NOT Recommended for a way to overcome 2-core mains if we have seen this on some amps. Only rewiring will do & EU users can use 3 pin plugs easily enough. Play It. We did & actually on Speakers it was better than expected, a little "cardboardy" on the midrange is the 1980s sound if Tone gives a good range showing it matches well. Appears made more for 86dB speakers as listening levels are loud enough for TV sound at "1", Tannoy Golds are 95dB. There is some sense of a good amp in there, the sound was quite lively, not hard to listen to, a bit of Bass power if still rather restrained on Bass & Treble overall to give that midrangey sound. Sound was clean, no background noise. A far cry from the Rough Sounding Thin 1980s amp sound other amps offer with all their Power Amp ICs. An interesting amp to have to upgrade.


Three Core Mains Cables Are Required For Amplifiers Today.

We've been rewiring old 2-core single insulated USA style mains cables for several years now. This is because the Case is Not Grounded & as today many amps are use without a Turntable, the Amp is not Grounded. This means a "Floating AC" voltage is present on the Casework, usually 50-65v AC if some can be higher depending on Transformer Construction. Today's AV gear & TVs aren't grounded as the Main amplifier is considered to be grounded, or it's just left Ungrounded which 'helps' bring on Failure. It is possible for this Stray AC voltage to Trash Electronic IC based audio gear as we found with Soundcard Failure. Amps we rewire to 3-Core Mains we don't test to see the floating voltage as it's always there & the AC Voltage can vary depending on the way the unmarked or EU-US style plugs are used. The 1985 Grundig CV-1460 as blogged just above we tested to see what it reads. There is no 'Double Insulated' Square icon which only means the cable is Double Insulated & Connectors meet a certain standard. Too early for the "CE" icon. It read 55v & 65v AC based on how the EU type plug was plugged in. Our TV & DAC isn't grounded & we know from before that it "doesn't like" 60v AC ground potential. The owner of it will want the Moulded Plug so no easy way for us to Ground it so we'll not be able to try the amp as it stands. To test the AC potential on Electrical Items to use a Multimeter to the Case & the other probe to a Mains Ground reference. We rewired the 1984 Sansui AU-G90X to 3-core as it needed the Ground to lose a mains type high pitched hum that showed on Headphones, done to 3-core the noise goes. To wire an additional plug with Ground to connect to the case, the Phono Ground would do & then use 2 plugs on it. Hifi needs Grounding & relying on a TV etc to ground it isn't going to happen as these items since the 1980s are always 2-core mains.


Hifi Time Travelling: 1972 Trio-Kenwood KA-6004 as Original & Upgraded.

We have two of these, one we've recapped as we couldn't test it on speakers as DC offset was too high & the other one which reads fine so to try after trying the Dual CV-1460 on speakers the same day. The upgraded KA-6004 is upgraded to a quality to sell, losing hissy transistors & recapped, if not upgraded as much as our KA-6000 is. Pre Out-Power In on the KA-6000 is a 100mV level if the KA-6004 adds a transistor on the Filter Boards to give a typical 1v output, if using as a pre-power amp complete it makes no difference. The KA-6004 displeases for the messy Filter Boards with Unshielded Cable on some Audio & those overlong cable wrap posts which may cause difficulty in upgrading more, we tidied up the upgraded one as the pins are just too close together. 6000 is Capacitor Coupled with Semi Complimentary Outputs, the 6004 is Direct Coupled with Relay Safety & Fully Complimentary Outputs which is unusual for 1972. The KA-6004 is underrated for sure & we've had several of them now, if not for a few years. The KA-6004 is a great affordable amp now the Asking Prices on the KA-6000 are now very high, if you can still get them in USA Auctions at better prices. The 1969 KA-6000 does need a big rebuild, the 1972 KA-6004 is borderline usable if the Relay is reliable, the rebuild on the 6004 isn't so big. On speakers we've had our version of the KA-6000 fairly often & for the last week, to know the KA-6000 sound to rate the Dual CV-1460 below. The KA-6004 we have two of, one is recapped & now sold, the other is serviced but original, so gives two versions of it to try. KA-6004 as Original. This one tests DC offset well, so to hear the KA-6004 as a buyer in 1972 might have heard it. The Dual CV-1460 was decent if rather restrained, the KA-6004 as Original was much better, wider Stereo & volume set to a typical "2-3" level for TV listening. Not so far from the KA-6000 'signature' sound which is good for an Original amp, but soon it was found the Bass was a little Slow & Thick in that typical "Retro Bass" way that does spoil the sound of many amplifiers, not the bad "T" filter sound, if buyers listening to Original amps will wonder why we rate these amps highly once Upgraded if the Original Sound is with Tubby Bass. It's how they are made & to try to hear them in their Original State is why we do the "Time Travel" reviews. The KA-6004 beyond that does sound a great amp if it needs our Upgrades to be it's best. KA-6004 as Recapped & Upgraded to a certain level, if not as much as the KA-6000 gets a play next, what do Our Recap-Upgrades sound like? DC offset on the recapped amp is very low around 3mV which will reduce to near zero with a speaker load on. Noticeable instantly is to not need Bass & Treble set the same, a notch back on both gives a good balance. The Tubby Bass sound is now opened up to sound more natural, the amp just sounds faster & fresher. It is noticeable & some amps do upgrade well for our improvements. Our KA-6000 as a Reference. To try this next, the sound is a lot more opened up & "effortless" which is a huge job to do & took us 2 years to get to this level. It would take a Trained Ear & Top Speakers to hear the difference which is why we rate Tannoy Golds so high. Verdict. Original KA-6004 we'd find a bit frustrating as well as being wary of 47 year old capacitors, if many do use amps this old until problems crop up, we'd not risk our speakers. Upgraded KA-6004 is a quality sound & better than some other of the same brand, but Much Upgraded KA-6000 with a few years of upgrades is naturally the preferred one & why we keep trying to go further, Upgraded KA-6004 really is a great amp & more accessible to the buyer as not such a hard upgrade compared to the KA-6000. KA-6004 may not have the KA-6000 looks, but it has a sound that betters the Sony 1971-73 range.


The Bigger Trio-Kenwood KA-8004 Must Be Better Then?
We blogged about the KA-8004 before in a Feb 2018 blog about Overdesign as the Phono stage is like a Push-Pull Amplifier stage long before others copied it. But a feature that probably makes the KA-6004 better than the KA-6000 is lacking in the KA-8004, it doesn't have two transformer taps, ie one for Power Amp & one for Preamp. Remarkably it just has one if a Sub Circuit that lazily uses Zener diodes to pull the voltage down to the Preamp Levels that need the ± voltages for the Push-Pull Phono. It comes direct from the 2 Main Capacitors & Main diodes via a small Resistor. This is rather shockingly rubbish design for what is supposed to be a better amp. Be sure the Design of the KA-8004 inspired a lot of later amps, clever ideas but not in the name of quality. The rather Hidden Sub Circuit is a secondary Power Supply with No Regulator but the Restrictive Zeners that we see as lazy design. The KA-8004 is better built inside if the Heatsinks are on opposite sides so as with the KA-6000 there are long wires between PP Drivers & PP Output stages. Who else looks at these designs to see what is good & what is a cheap out? No we don't want a KA-8004 now & did see a 110v-only one on USA ebay.


EU & UK Amplifiers: Our Verdict On Trying More.
The sound of UK & EU Transistor amps in itself is not a Bad Sound, we liked the Leak Delta 70 amp on getting one in about 1991. We've had a few of the Stereo/Delta 30/70 & the Delta 75 receiver, plus several Bang & Olufsen 3000/4000/4400/1900, didn't fancy trying the Rogers Ravensbourne/Ravensbrook after getting the lower model amp about 1990 & the receiver as reviewed by us. We've recently tried a 1966 Grundig SV-80 as blogged above & were glad it got returned. The 1971 Revox A78 once serviced sounded nice if rather soft on treble, so we just sold it on as we didn't fancy upgrading more or recapping as we could see it'd not upgrade too easily & wary of the typical EU amp issues. We did try the 1970 Goodmans Module 80, an amp we used in about 1990-92 so in 2016 to give it all the Recap-Upgrades that are tried & tested on many amps it revealed problems as the review tells. Interestingly we get a 1985 Dual CV-1460 here to upgrade if it's quite a different deal here. The Trouble with UK & EU amps is they are made on the cheap. Look at the poorly made UK teak wood cases & then look at a Yamaha one. Look at the ancient Components cheeky Armstrong still put in their 1968-72 range. The EU amps suffer like their Cars do, they may have a certain style, the 1950s Citroen 2CV with the corrugated lid now looks stylish, but it's made like a dustbin beyond the bonnet, the corrugated look was as the metal was too weak. Cheaping out in that Continental Build way on the Revox with only the easily damaged control knobs holding the wobbly rod of the control in place. We've had enough TVs & Radiograms to see the Workmanship & frankly it's not very good. Metal Fatigue is a problem yet never with Japan & USA amps, beware adjust pots & push-on post connectors, the metal crumbles away & be sure there are more issues hidden the more you take it apart. A Ferrograph mid 1970s amp & tuner we had, the untreated bare metal turns to grey oxide dust, not red rust, to show bad metal. Ferrograph amps are very low spec with huge AC ripple that seems to be accepted on UK-EU amps. The thing is these amps can Sound decent, the designs limit our upgrading & even using new capacitors with wider bandwdth will cause issues as the design was made for those TV-Grade axial or plastic cased capacitors. UK's Armstrong was The King of Crappy Made Amps, the valve amp by them was laughably poor as are their bulk buy-out Germanium transistors used until 1973 on the 500 range. They are just product to last like your Phone today is only made to last 2 years. Here we expect the better amps 40-50 years old to recap & upgrade to be 'Excellent' as we rate Upgraded amps often. This is clearly not possible with UK & EU amps. So we avoid them as they are More Trouble Than They are worth. But There Is Hope. The 1985 Dual CV-1460 95w amp reveals why, as does the 1978 Leak range. They are Made In Japan. The labels say "Made In Japan under Dual specification" and the Leak 3200 with it's DIN speaker outputs & aerial sockets is made to Leak design. The risk by 1978 is that ICs will be involved, in the Phono is typical except on the top models sometimes. In Tone they are a bit limiting but in the Power Amp beyond things like 2 transistors in one package to have matched Differential pairs which is good, the IC is No Good for Real Hifi. UK & EU brands Made In Japan are a different thing, they use superior parts, be sure a budget amp will still be made like a budget amp with hardboard bases & rear panels, but your Budget Gear will last longer than UK-EU made gear or similarly the Made In China stuff of today. This opens up the idea of trying more EU & UK amps, as the Brand Names are familiar, but by 1978 the cost cutting & the consumer demanding low priced items still means there aren't going to be many. The Best Hifi 1965-1977 is made in Japan or USA, even USA Marantz got made in Japan on the 1971 Marantz 2245. a lot of UK-EU brands faded away by the early-mid 1970s as they could not compete with the quality & Price of the Japanese amps. Wise Man Copy Best & Make It Better At Better Price is the Ethos there, they copied the USA brands. Now Made In Japan quality seems forgotten a Made in China etc as they undercut, but the quality of Made In Japan hifi is really what made the Hifi Scene once it got big by the early 1970s.


1967 Sansui AU-777 Amplifier.
We've liked the 1966 Sansui TR-707A & 1967 Sansui 400 receivers, they are high quality sounding amps & upgrade extremely well. But they are Receivers with Tuner stages, so what else did Sansui do in Amplifiers? The Valve Sansui we've had the rather poor Sansui 500A & the bigger Sansui 1000 & Sansui 1000A are "difficult" amplifiers too. Sansui certainly their best with Transistors & the Sansui TR-707A does predate the Sony TA-1120. The Sansui AU-777 from May 1967 says a tube-amps site page that appears accurate, if it does miss the 1966 Sansui 3000 early version of the 1968 Sansui 3000A. Not a 1969 amp if there were later variations, the AU-777 is a 1967 design & the manuals are all crisply scanned which makes a nice read. Looking at the User Manual, it shows the back panel has 8 output transistors. The Fascia is the All-Black style that Sansui did for years. Manual states 25w per channel into 8 ohms, the Doubled Outputs suggest it's possibly underrated as the TR-707A was found to be 18w into 15 ohm as it read like a 30w amp. Gives 24 Damping Factor at 8 ohms. The Power Amp shows there are 8x TO3 transistors, if 4 are Drivers & 4 are Outputs. 2SD143 15w 3A for Drivers and 2SD46 50w 5A for the outputs like the TR-707A has on early ones. The early Trio-Kenwood TK-140E is the only other amp we've seen TO3 drivers on, if one was a TO66 trying to do a NPN-PNP pair. Aux to the Preamp, not the lazy Through Big Resistor & Into Aux that Sansui unwisely did on the 1969 Sansui 4000. Aux to switches, Volume, Balance, NFB Tone stage which is very complex with Flat, Cut & Boost switches plus stepped Rotary adjustment. Further along a Muting stage, the whole preamp is very busy & it'll not be as precise as the TR-707A or 400. Pre Out-Main In connectors. A 'Presence' switch is in the main NFB that'll add midrange, much like the Sony STR-6120 one adds extra Bass & the McIntosh early preamps do similar. Some of the design is very complex to the point of overdesign & strange things like an Inductance Coil in the Output Transistors to reduce HF is bizarre as this is done in Tuner stages usually. Design is as crazy as the TR-707A if the Sansui 400 is the total opposite. Sansui AU-777 certainly is an interesting one, too many features that will reduce the sound a little if otherwise it should sound very good, if a 1967 amp will need a full rebuild by now & this one looks a big job. Later versions are AU-777D from June 1969 now 30w with design changes & a AU-777A likely 1970-71 if they all have the 8 rear transistors & all on 80v main capacitor shown as 70v HT on one version suggesting 25w RMS into 8 ohms is correct. an interesting amp, if we have a few Sansui as of typing, so do we need 4 of them? One turned up on ebay with damage at the back if noice in the woodcase, but their £1150 price is just ridiculous, it'd make the £150 like that to one who can fix & get the broken bit, but sadly that's ebay greed for you. Let it sit, sometimes they do that & then offer it at a low start.


Tone Stages: There Are Two Design Types.
The Most Commonly used Tone Stage design is the Baxandall one designed by Peter Baxandall was introduced in 1952 in "Wireless World" says Wikipedia. It's in the Rogers Cadet III & HG 88 III amps & in just about every transistor amp. It does the job well enough as it relies on NFB which is Negative Feedback between two stages or around one Transistor. Easy circuit to build & the Standard Tone stage or variants are everywhere. The other type is fairly rare to find, you do see it in some 1960s Transistor amplifiers like the Sansui TR-707A, Sansui 400 plus more we'll search for & it was first noticed by us in the Sony STR-6850 which is based on the Sony STR-6050, the Sony STR-6040 also. This we consider to be "Passive Tone" as it doesn't rely on NFB & uses 2 ground references. The first amp we had with this was the 1967 Trio-Kenwood TK-66 & having got one more recently in 2016 we rebuilt the Power amp to see how good it'd be, but the Tone Stage was a bit muddy & despite the amp getting an 'excellent' as upgraded, the Tone stage was initially thought inferior as not a Baxandall type, if now to see it's not designed optimally. The thing with this design is it needs to be done right or it sounds inferior with Bass too thick & Treble too soft. This limited the 1963 Trio WX-400U similarly if we altered it to sound better, it wasn't easy to get right by trial & error. Other amps with the 'Passive' Tone we added here as we found them so it's a bit random, Akai AA-5000(S), Akai AA-7000. Marantz 1030 15w amp uses this design too interestingly & likely other low power Marantz receivers do too. National-Panasonic SA-65, Rotel RA-610, Rotel RX-800, Sansui 3000/3000A, Sansui 800, Hacker GAR500/550 & Toshiba SA-15Y. Akai AA-6300 a 20w receiver, not the 40w some say & Akai AA-6600 also. Pioneer SA-500 the 13w 1969 amp. Trio-Kenwood on the KA-2002(a) the 4ch receiver KR-6340 has this design too if the 3 other in the range don't which is rare as late as 1973 which is interesting as we only got that late 2018 & hadn't realised the benefit of the design until the 2 Sansui 1965-67 ones. The JVC 'SEA' EQ sliders use a mix of NFB & Passive Grounding, unlike the IC type Graphic EQ units of later years. So what's the Interest to blog & find out which Amps use Passive Tone? It sounds a lot fresher if done right, no NFB to flatten the sound creates a bigger more open soundstage. Midrange using NFB Tone still has the NFB at any Tone setting, reducing NFB gives the Tone Gain, the NFB level depends on the circuit & typical ±10dB Tone range is less hard on the NFB than some other parts of the circuit explaining why it still sounds good. Some Tone Controls are 100k ohm, if others use 25k ohm ones giving more NFB. But before you throw out your Baxandall Tone Amps in search of more clarity, the Passive Tone stage really only shows the benefit once we've upgraded amps & assuming this more complicated design, based on picking component values, is done right. A Variant to the Baxandall Tone is one seen in some 1980s amps: it uses Tone in the Main Power Amp NFB loop, not the preamp. The Dual CV1460 has this so once the one we have is upgraded to see what that does. Another Variant is the Sony STR-6055 one that uses both NFB & Passive.


The Latest of The Passive Tone Control Amps from 1973.
As the above reveals, we have that amp, the 1973 Trio-Kenwood KR-6340 Quadraphonic Receiver. We liked this amp, the Power amps are pleasing if the amp itself wasn't as 'expressive' as some. But to know the Tone stage probably isn't designed optimally so the Bass on the amp wasn't as good as expected. The Bridged Mode gives an output voltage in the league of a 90w amp if it's rated 50w, the sound was clean, but had quite a bit of unshielded audio cable as the amp is so complex. It's possible some later amps with too many ICs have this design if they are so overdesigned it's hard to tell on one such as the Trio KR-11000G/Eleven G. Any with IC Tone stages have NFB as per the 'op-amp' design so easy to ignore looking there. But looking at the KR-6340 Tone it's not quite the same as the other designs, it might work out well, but for how hard it was to get to the Tone board to recap, it'll have to go undiscovered which is a shame in interests of trying things. The 1973 Yamaha CR-400 we have here has a typical NFB tone, if one to look out for in future amps.


Luxman L-100 Amplifier - 100w From 1975.
We had one of these in Sept 2012 & it had a lot of messing inside, missing relays & plug-in connectors that we managed to find, if recapped it all beyond the 2 huge 'Soup Can' sized capacitors, if found it soft as original, better once Serviced & all Recapped still found it quite tame sounding & didn't like the Phono stage, but that was nearly 7 years ago & many amps here since. One we've not revisited yet. To re-read the review & see we didn't like the 22-Step Volume control & the insane thing goes to zero if you could accidentally put it to Max by going round one more notch as there was no zero stop & we did take the volume apart to see if perhaps the stop had worn away. Had it the same time as the Sansui AU-999, Pioneer SX-1500TDF & Sony TA-1120A & remember liking the Pioneer & Sony more, if we didn't used to play them on the main speakers, only smaller test ones. "Weak On Master Volume" isn't a term we use now in reviewing, but it meant the amp didn't have much kick to it even turned up more. the Headphone circuit was too low volume also. Further Luxman like the R-1040 receivers were just everyday receivers of nothing special-ness plus the gaudy looks. Then the Rosewood veneer on a thin wood outer case looked a bit cheesy if they are in Teak too. Revisit compete there, but the Circuit needs a look, it's not very well drawn not following the typical style so is a mess & hard to follow without typical circle transistor icons etc. The Circuits. Phono has a level-adjust pot like the Pioneer SA-9500 does, switches then a Relay, Phono Stage has a crazy 12 Transistors plus a few Diodes, it looks as overdesigned as it sounded, not even the 'Linear Equalizer Tilt' control that alters the Phono EQ could better it, if perhaps this was fiddled with on the 2012 one as were missing parts. The Preamp-Tone stage including Filters is a nightmare, is this a Tim De P design as he did the expensive Pre-Power C-1000/M-6000/M-4000 ones that we know are ridiculously overdesigned to get "Perfect Specs" at least on the C-1000 preamp as blogged before & started the 1976 'Specs Wars' where 0.01% THD is considered important yet the mangled sound isn't considered distorted. One stage is the Class B Push-Pull stage needing 10 transistors per channel. The 16-transistor Filter Stage is impossible to work out with all the circuit lines if it looks like there are 4 per section that are Filter amp or Buffer stages if we'll pass on looking further at that as it's just awful. Power Amp with Doubled Outputs are on two very small boards fitted to the heatsink & to remember that being annoying. Too hard to tell if circuit lines cross or joined here. Power Supply we remember was difficult & it has Zener Diodes to pull voltages rather than a Regulator. Just remember it sounding 'bouncy' on the Bass but just so Boring suggesting high NFB in multiple places & we can see it now, what an awful design. Looking At Our Sales Photos. We sold this in 2014 after letting it sit unsure what to do as some of the sound was nice, but it was just lacking any life to it which the circuits reveal now. Way overdesigned with some poor user features. The Photos fill us with forgotten dread, to see lots of unshielded audio cable, a pointless "Attenuate" feature again as the SA-9500 does to make finer use of the mediocre limited Stepped Volume Control. The "Winker" feature is a soft-start, rather than describing the designer. Layers of preamp boards with no grounding between as the Revox A78 has & we couldn't wait to get rid of that amp. Verdict. The Luxman L-100 is an amp we'd avoid for getting ourselves having had one to know the sound is overdesigned & very Flat sounding. Bass was nice & why the guy selling it was into Reggae with it, but he sold it & so did we. Smart-Ass designer doing far too much complex 'superior' design & ruining the sound in the process. Space limited inside for the huge caps & lots of problems beyond the ones of missing parts. This isn't Hi-Fi to us, it doesn't play Music well, some may like it as it could tame rough speakers if why keep them. Even the Gaudy 1978 receivers sounded fresher if rather cost-cut in build.


Luxman L-85V Amplifier - 85w From 1978
On seeing a L-100 as blogged above, to see a similar looking & similar power L-85V needs investigating. Not one the Hifi Yearbooks showed if they became inaccurate by 1978 so it will be a UK sold one. Luxman has a "Prestige" reputation, but so do Bang & Olufsen if more for the looks & user features than the sound & audio design. Their earlier late 1960s Transistor Amplifiers are rather basic made with lines of boards & not much space, they'd clearly not seen how Pioneer, Sansui or Sony did design & we're yet to find or want to get a Luxman to try earlier than the 1975 L-100. HFE says 1978-79 then says 1975, the fascia design looks more 1975 like the L-100 if the matching tuner looks like the 1978 receivers so as the L-80V is in the 1976 HFYB to go with 1978 on this seems best. Schematic shows a much simpler amp than the L-100 mess, if straight away ICs & Zeners for Voltage in the Phono isn't great if that's 1978 style, but an IC then a Class B push-pull stage for just Phono is overdesign, has the 'Linear Equalizer" switch as the L-100. Tone looks better, just 2 transistors per channel without the heavy NFB of the L-100 so might be worthwhile. Power amp the usual differential if a lazy Zener again if otherwise looks good with single outputs which shows it's 1978 as Yamaha put single outputs, ie not parallel pairs to get higher power. Pity about the Phono stage as the rest looks good. An 'insidehifi' site has lots of pics, if not taken apart further as boards face down so not to see, it reveals the sort of 1978 build the Gaudy Receivers have, not too impressive & shows the cost-cutting compared to the 1975 L-100. One on ebay for £450 for us to notice it, the Luxman numbering is very random not to tell which models are low or higher ones, this reveals the amp's looks. The cheesy 1978 build shows with the plain fascia & gold control knobs. High grade amp, the white paint in the AC outlets was from plugs blanking these so best left blanked as paint will restrict contact. For a buyer of an original amp it looks a decent buy, not for us to rebuild & try to get upgraded prices for though. The fact is a 41 year old amp will always improve with a Service, it may be fine on the original capacitors, but knowing their 1978 receivers, the spec is rather penny-pinched which could be hiding a decent amp based on the main stages.


Make Your Amp Seem Louder For Free.
This is just a Mind Trick, but as with Tonal Balance, you as a Human are easy to fool. The Sony Volume Control has a slow taper meaning it needs to go up to about 4.5 to be a typical volume yet by 6.5 it's very loud. This is offputting as it takes more turning to get it louder and risky as you could knock the volume & set it too high. If you have an amplifier with the pointer for the Volume not fitted right & the pointer is perhaps one notch up further than it should be, can trick you into thinking the amp isn't so loud as it needs to go higher, as in "needs to go to 5 to be the right volume". Amps we've tested with the fascia & knobs off you have no guide on a rotary, so to think the amp sounds good & loud, but then put the Volume Control knob on correctly & see it turned up higher than you thought, one amp was sounding good yet it was at '6' to be that loud when put back together. Yamaha CR-2020 amps we've had & seen used ones with finger dirt marks showing it never goes over '2' on the volume. The 110w amp seems very loud. So the trick is your amp seems louder if the pointer doesn't turn as far, as in put zero at a minus one position. Fool your Friends in how efficient your amp is by fitting the Volume control pointer higher than it should be, only needs to go to '2' to be that loud, just like the Yamaha CR-2020.


1973 Sony TA-1150: Testing The Preamp Tone IC.
You can see the results from the Marantz 2385 IC, it didn't do too well with high Treble using the Treble Tone control. So the TA-1150 is getting treated as harshly as it has an IC for Tone. Is it fine or does it limit? 1kHz at 0dB, with the Power Amp Coupler set to 'Off' has a 1v reading just a shade over the '5' setting, at the same settings 50Hz reads 0.9v & 10kHz reads 1.05v which is reasonable if could be bettered perhaps. On 50Hz with Loudness off, Turnover at 500Hz & 2.5kHz the typical settings, the Bass set to Max goes to 4.17v without any clipping. On 10kHz Treble at Max goes to 3.14v without any clipping. Perfect Sinewaves if Max Treble is a little reduced from Max Bass reading & this was noticeable on Speakers. This output is what the IC outputs, the Buffer transistor before it adds no gain. 50Hz on Max Bass goes to 9.5v before clipping starts which is just under '6' on the Volume. On 95dB Tannoys the amp was a good volume at '3'. 10kHz on Max Treble goes to 9.7v which is just over '6'. Is that any good? 10kHz when 9.7v at Max Treble reads 3v set to zero, the Tone knob pairs the rear one on a screw lock is set spot-on midway physically if the splines for the front one aren't in line annoyingly, if the pots L+R are set flat. 50Hz when Max Bass reads 9.5v is 2v set flat. Bass is a little restricted therefore by the design if the IC is no problem at all & compared to the Marantz 4070 it's clear it actually betters it. The TA-1150 preamp is actually better vthan expected if the power amp was later found to be not as good as the TA-1140 one. The TA-1150 preamp with the TA-1140 power amp would be the best, as in using pre out-main in cables.


The Smallest 1973-74 Yamaha Receiver: The CR-200.
We've had the CR-400 & have another here as of typing as it sounded a lot better than you'd ever think for a 16-20w rated amp. So to see the CR-200 on ebay with a Metal Top Lid with wood effect finish. The manual shows a CR-200 & a CR-200E which is the Export version with a vinyl wrap wood case as typical Yamaha. Far from being a Piece Of Junk as we found with the CR-400, this has IC for Phono similarly, Tone is 2 transistors per channel much like the CR-400. But what's interesting here is the Power Amp. It's a Capacitor Coupled design without Differentials, working on a 45.2v HT which means it's similar to a ±22.6v HT on a Differentials-Complimentary type design meaning about 16w RMS output. This appears in the 1975 HFYB as do the other CRx00 ranges that were introduced 1973-74. We have the 1969 Yamaha AA-70 receiver printed manual, this CR-200 is based on that design if not exactly the same, it is still an older circuit design. We've seen the AA-70 before but it's not found in nice grade as it's oversized to fit a record deck inside to be sold as a Music Centre as it's 480mm wide, 440mm deep & 138mm high. Power supply is very minimal with a Bridge Rectifier & one 3300µf 50v main capacitor with a basic regulator to get the Preamp & lower Tuner Voltage via a resistor. The circuit is tamed, but it's a quality design still. Inside it's a one-board job with all circuits & power supply together if white lines to split the design. Empty space at the back for the one board if a reasonable sized transformer & a modest folded heatsink panel. The 1969 styled power amp could sound interesting, the CR-400 we thought could upgrade more if space on one board is limited. Looking on Google to find Forums for inside pics, one is asking a stranger how to fix one of these. We get one so it'll be on the reviews page.


Retro Digital Clock-Lamp: 1977 President Timelite.
We had this as our Alarm Clock-Reading Lamp when at school, pictures found of it on Google. Actually had two of them as the first one went wrong somehow, so to find another one for Nostalgia purposes, they are around on ebay for about £35. The cream plastic like most plastic unless kept in a dark room & the lamp not used means it goes brown which is just how plastic ages. The unit must have been a popular one & not an expensively made item. Three screws you need to make holes in the green base cloth to unscrew & then to see the original colour was a lot lighter, but that's old plastic tech. Not much in it, a transformer, 2 fuses, a buzzer unit, a panel with 4 LED number blocks & a lovely piece of black coloured cardboard to hide the PCB. On the back of the PCB is a large IC with MM5387AA/N, the IC has 40 pins. the PCBs have minimal components & just 2 capacitors 220µf 16v & a 100µf 25v so the IC works from the Transistors which we assume are Regulators. To recap those as they are 40 years old. The IC has a "/814" which could mean Apr 1981 if the LED sections have "T7732" which makes more sense to be 1977 for the Red Numbers style isn't a later general type. The Problem here is the 6 push buttons, the front line of 5 & the Snooze. These are 'Momentary Microswitches' of sorts, the track on the PCB & 6x 10mm sprung metal discs create the 'pop' effect. But these are just held on with Sellotape with a thin Foam Layer to create the Bounce & holding high in pressing the button. Not high tech at all, it's just Everyday Electronics. The buttons will have been pressed a lot & this lets the buttons age as old foam turns to dust. But once the metal bits are serviced, seems fine, if then you find the plastic press buttons are malformed so the pointy middle bit doesn't push the sprung metal part right & why these fail as the buttons go bad, if you can have fun & rebuild them as we did. Lights up fine plugged in, the buttons are locked by a small slider switch behind the lamp arm. A piece of tape with 2 holes in limits the leftmost display line to just show dots, low tech again. The light has high & low settings, a little flicker on the lower one. The bulb is the same as a Car Indictator Lamp used in the mid 1980s so likely a LED one will do. The filament bulb is marked "12V15CP" which are on ebay, so CP means 'Caravan & Interior' type bulb, but this is 2019 we want an LED. To find one that fits & is a White Light not the Amber Indicator needs searching. How would the circuit cope with the High-Low brightness. As with LEDs in Amplifiers, the LED light is too narrow beam. Seeing what there is, we leave it be as the Filament bulb. To wait until they make the Bulb Shape ones like Domestic Bulbs, if that's not likely if none are out there now. Old General Purpose Electronics can be serviced & fixed, but to offer repairs on them we'd not do as once you encounter broken bits that are missing or can't be replaced, the item is only good for parts. To think it's an Hour job actually takes 3 days to get right, to rebuild the buttons section including drying time. Simple Jobs can take ages. Looks so 1977 Retro now with the old-style Red LEDs smaller than the type that has been standard since the early 1980s.


The Trouble With Not Liking Your Turntable In Your Hifi.
We got a message asking about the Technics SL-1500 turntable we have for sale. They have 3 turntables already yet aren't happy with the sound. The Sony PS4750 is a Direct Drive in the same league as the SL-1500 yet it's thought to sound "thin". They have a Goldring Lenco L-75 idler turntable & an Ariston RD11E and find these sound better if they lack detail. The L-75 was o step up from the Garrard SP25 Mk III used in many music centres at the time yet they weren't so reliable is the idea we get from reading the Hifi News mags. Ariston were early 1980s midprice sort of decks with belt drive, never of much quality if they sold well in the "What Hi-Fi" era as they were good value for not much money. If we had to pick one we'd go for the Sony as ebay prices show it sells for around £150 much like the SL-1500 used to. Direct Drive is the Best Turntable design, we sold our 1950s Garrard 301 after all as the Technics SL-120 could be upgraded to sound as good & be much better to use. Idler wheels are just below in qualoity, both have good Torque so DJs can cue up & 'scratch' on these decks. The Belt drive is the mainstay in cheap plastic turntables & despite some Expensive Turntables using it with a feeble motor & a glorified rubber band, these have poor Torque & Belt drive is way down in our estimation knowing it's the cheap option to build. So back to the sound, the Sony on a quality system will sound the best for detail, the others are mediocre so will not reveal weaknesses in your Hifi. The one realising they need 3 turntables has yet to question their amplifier. as out Turntables-Phono page tells, the majority of Phono stages are mediocre, they are soft & blurry to the point we wonder how people can listen to such imprecise mush. We've used our own Valve Phono stages since year 2000 & the one we record tracks to the computer with is a 2008 version of an earlier 2004 version. There is Mastertape Detail in Vinyl, yet all we hear told of Vinyl is "Warm Sounding" & hearing 'The Gadget Show' doing tests of ordinary Turntables & Phono stages in amps, the detail isn't just warm it's severely dull & weak. If you want to hear how Vinyl Done Right sound, see the 'YouTube' link at the top of the site, this sound beats commericial CDs with ease. So the guy with 3 turntables doesn't like them & really the amplifier's Phono stage is his problem. They should get a better amplifier is the real answer rather than get a 4th turntable that they'll likely think sounds "thin" too, but then if they manage to get an Amp & Turntable match then the Loudspeakers will be the next weak point. Upgradey-itis is a game to cost you money & some forever chase their "Ideal Sound" which in terms of Vinyl is not a cheap game to play. Then once you have Mastertape Quality from Vinyl, a sound that no amp ever commercially made will have, then you'll be disappointed at how Lo-Fi some records are mastered. Many go the easy route of CD, a format supposedly out of date for MP3 Downloads which is sad as MP3s are Not Hi-Fi. This Hi-Fi Site is based on Our 30 year Search for Hifi Perfection, the truth is it's not out there & you must hit a healthy balance of "Good Enough Not To Annoy" plus "Good Enough For A Five Hour Session".


1977 Trio-Kenwood KR-6030 80w Receiver.
We've looked at Earlier Trio-Kenwood amps & receivers if not as late as this one from 1977 that is All Transistors beyond the IC Phono stage keeps away from the IC issues with others. This is the one the Three Turntables guy has, to see what they are using to get opinions & try to see why they aren't happy with things, can we tell how the amp sounds just from the circuits? Tuner has a lot of ICs if this is pretty standard by now, the crisp Tuner sound of earlier years gets lost in too much circuitry. Phono stage is ICs if the less complex HA 1457 one per channel if Phono stages even with all transistors often sound blurry & far from the crisp sound TV sound is, not saying CD sound as most CDs we don't like their 0dB chopped waveforms. Phono has 50K ohm + 47pf loading which isn't ideal but at least the Resistance Loading is right. Typical sort of design if we've not really bothered listening to IC phono stages after knowing how awful the later op-amp type ones sound. Preamp-Tone is 4 transistors per channel NFB Tone if rather tamed in places suggesting the amp will sound rather Flat & 'Domestic' sounding like a Compressor does to sound to make it sound 'safe', not a sound we want to hear. Power amp design is typical by now if interestingly the Circuit Labels the sections, Input as Differential, or Paraphase amp as Sony call it, "Current Mirror" is now what they call the Constant Current Regulator as seen in later ICs, Class A is the driver with part of the CM stage, then the usual P-P Drivers & Outputs. Earlier amps never needed CM/CCRs so it's a part of the Spec Wars control like the Marantz 2385 below similarly has. 12000µf 63v main caps if the rest is typically cost-cut plus the 'safe' preamp together with the typical construction by now doesn't make us want one, if it seems to be decent for what it is & like any amp of some quality it'd upgrade to sound a lot better, if still be rather 'safe' sounding without some tricky redesign that we have had success doing on another amp. One on ebay for £250 as an 80w receiver is not a bad buy & other sold prices show it's standing. Looks-wise it is very generic-bland & really doesn't look like an 80w amp should.


But That's How Our Amplifier & Turntable Sound: What To Do.

The same person said they liked the warm sound of the non-Sony record players on that amp. They say the Bass is decent if we can see the amp is rather compressed with Real Deep Bass lacking. They actually have a Good Balance with what they have & if they are happy with it, then stop looking further. But the trouble is they have heard 'better' in the Sony turntable for it's greater precision giving better focus, but sounding "thin" as the amp is revealed to be lacking. Here we advise the SL-1500 they originally asked about is not going to give the sound they want & suggest to read this blog & maybe consider getting the Amp Upgraded as the Blog on it above sees the typical 1977 cost cutting. A Dilemma Indeed. We know many keep chasing their "perfection" despite being happy with what they have, or had until hearing something better. The Hifi Mags used to go on about people being content with the system they had, but heard A Friend's System that likely cost 5 times as much & not being happy with theirs. Much like a man with a nice but plain wife suddenly getting starstruck on today's Fake Looking females & seeing Frumpy Jane isn't what they want now, more fool them. Be careful what you compare to as you'll always want to better your lot. You can spend a lot of Money on "Better" New Hifi from Shops spending Thousands on some thing Stuffed With ICs & still never get what an upgraded amp by us can offer.


February 2019 Blog

Marantz 2385 180w Receiver: What To Do With You Now?
This still gets used on our Speakers for TV watching because it sounds great now much upgraded. Other amps we use as of typing are Trio-Kenwood KA-6000 which is modified a lot, plus Sansui TR-707A the 1965 Germanium one & the Sansui 400 which is an update to the TR-707A if with us putting 707A ideas into it. The Sansuis are very rich & bassy which can please as much as it can get a bit tiring as 'Everything' is Bassy which isn't really how the world sounds, but that is Hifi, your Recreation of Sound to your varying tastes. The 2385 on speakers as of typing, we've serviced & recapped the thing plus a lot of upgrades the other 'rebuilders' totally miss. To understand the Power Amp isn't an easy one as the design has several transistor sets for Bias & Protection plus others for Voltage regulation which often means Limiting. Looking online if anyone has described the 2385 power amp circuit, we're way ahead on considering that & just find pointless rebuilds of the Preamp ICs & those who feel new Relays & putting higher voltage capacitors actually matters, yet they leave all the limited parts which shows they don't have the first idea of design. We certainly don't understand the 2385 power amp circuit completely, some amps describe what the Stages are to help understand, but Marantz never do which gives the idea there are compromises. Q709-715 are 'unusual' & even the Marantz 2500 doesn't have this design. Sony TA-3200F labels the sections which is useful to learn from, R110 does a similar thing in Current Regulation to Q709-711 if why the need to regulate? Q713-717 are Bias & Driver related if Q713-715 with Diodes to the transistors is just obscure, why are they needed for the Q717 driver? A Power Amplifier is really just Input stage, Driver, Bias Stage, Protection, P-P Drivers & P-P Outputs. anything else is the whim of the Designer adding circuitry to get lower THD which usually limits the sound along the way. The fact the circuitry isn't in the 2500 or other amps shows it's probably not needed or is even a compromise to keep the Amp stable. A less kind term is "overdesigned crap" and many amps are guilty of that by the mid 1970s. We won't take out questionable circuitry because firstly the amp is 180w & not for meddling with plus it's there to keep the design stable to some degree. To try to improve on what there is unless it's clearly bad design in any part of the amp is how we do things. So this Blog has helped find what does what if seeing parts that are not in other amps means they'll be just accepted unless more info is found, if the Specs Wars 0.01% THD is likely why. At 8 ohms THD is rated at 0.01% THD if IM distortion is 0.1% which is on paper no better than September 1945 Harold Leak getting "Point One" distortion in his amp range of the same name. Some changes made the slightly tame 2385 into something more like the 1965-67 Sansui amps, which is why it's not on the Sales page now, if only really there to show what we can do. We can probably make your Dull & Boring Monster amps sound like they really should, ones without IC Power Amps though. We decided to keep it up for Sale as on the 'Sales' pages as it gets interest showing we can do amps like this & as well as if we get a sale on it, we'll try more amps in the same league as it certainly is interesting.


Current Mirror aka Constant Current Source: What & Why?

The Sony TA-3200F Power Amp from 1970 is probably the First Amplifier to use this design as it's not in any we've had earlier than that. Transistor Q104 has 62v on the Emitter, 61.5v on the Base & 0.5v on the Collector, based on our readings as the manual is barely readable on voltages. 0.5v to the Differential Long Tailed Pair as they get called. R110 is a 47K ohm resistor between +HT & - HT with a Double Diode in the Circuit. What that's for is a bit of a mystery, it seems pointless to us, but we'll find out more. The 1977 Trio-Kenwood KR-6030 has a similar circuit & calls it a 'Current Mirror', a term often seen on ICs if never explained or the compatible circuits shown. The 1973 Sony TA-1150 has ICs for Phono & Tone & it's similar circuit is called a 'Bias Circuit'. The KR-6030 'Current Mirror' on the Power Amp, done as all Transistors has the Current Mirror with the Bias which has no Adjust Pots so appears Autobias or Fixed Bias as some 1960s Transistor Amplifiers are, but isn't. The KR-6030 does show how to Bias if not by the usual Adjust pots but by awkwardly changing Resistors in the circuit if the reading isn't right, have seen this bad non-adjust design on one other amp if to remember which. Again to Wikipedia, their tech info is trustworthy at least, see the Annuals page for more on Wikipedia. Basically it's a Current Limiter & why these circuits are needed is the Mystery of The Specs Wars where restricting circuitry gives it the 'ideal THD'. Wading through theory makes your eyes go blurry as it never explains why it's needed. It's to do with Impedance, an amplifier is designed to be good amid itself so why need it to be universal if it'll never be needed. It's trying to control & regulate what doesn't need it, but again Specs Wars is why, restricting certain behaviour gives the 'important' specs. Older amps in the early Power amp stages you can see from Circuits that they never needed this, so do they sound inferior? It's probably like any Circuit, for us to think Differential era amps were not so good for the Differentials long proved untrue as by the time the Differential became standard the cost cutting reduced the sound. It's how good the design is & how freely costed it is, as what upgrading found with the 1969 Teac amps that have the early showing of the Differential. A lot of "Fancy Design" is more a fashion thing, we stripped the 2005 Marantz PM-6005 from over a hundred limiters to see the design was little different to a 1977 Yamaha one. There is no progress in Analog Hifi, just fooling you & giving you Built-In Obsolescence to go buy a new one in 2 years. The More Simple an Amplifier is, the less restricted the sound is. Any extraneous circuitry is a form of regulated sound shaping & compression, to get the Magic Specifications as started around 1975-76 in the Hifi Magazines & the Tim De P guy with that Luxman preamp in 1975 started it. Very Low THD if the sound is mangled, it only matters the THD is very low as you can't measure how mangled the sound is. As on our Intro page & what we thought several years ago... "If they were more honest they'd rate it as "Percentage Of The Real Sound we actually Lost in search of High Specifications". Some rough sounding low spec penny pinched amps are so distorted from the real clean smooth sound they could be easily 50% Distortion.


The First "Bad" Loudspeaker Review November 1970 HFN/RR.
Having read the 1956-80 run of the Hi-Fi News magazine that became HFN/RR with the previous October 1970 issue, to pick out Bad Speakers we see in Reviews as we've blogged before like the Celestion Ditton 22 and 44 that have very badly designed crossovers leading to the "Difficult Load" that these speakers get called, Amplifier Wreckers is more the truth. The one here is an obscure brand the "PWB Audio NS-4" that as with all of the 'Difficult load' speakers is actually a 4-Drive unit speaker, the company make a NS-2 speaker with the typical 2-Drivers. But the 4 driver one is the stinker. Seems to be a Cottage Industry from a housing estate in Leeds. PWB is Peter Belt, an unknown name. The review waffles on trying to justify 4-Drivers to match the ESL Electrostatic sound & claims it knows 'good engineering'. NS-4 uses a KEF B139 bass unit & 'three special versions' of the T27 tweeter if no picture is shown, the NS-2 is found online as an oval shaped driver with tweeter above. Appears to be using three tweeters to make the treble appear more smooth by having more. You may be able to see the problem with that already. The design is done by ear which is good to a degree but he's clearly not tested the speakers as above 2kHz the impedance using three tweeters at once causes an extreme impedance dip. The text says it goes to 2.5 Ohms which is bad, if the graph here suggests it dips to 1 ohm at 10kHz where there is still good treble energy in Music. Impedance Curves are the Load the Amplifier 'sees' at certain frequencies, it's not the Frequency Response you'll hear. This is a disastrous 1 ohm load for any amplifier, most amps will only take 4 ohms or 2 pairs of 8 ohms, only later amps by the 1980s can deal with 2 ohms. The reviewer, Ralph West is a well-known Hifi name if he says "shouldn't really upset any decent amplifier". But that also tells that Ralph West is one of those who are just using a Quad 33/303 that is specifically designed & tamed to suit the difficult treble load of the ESL 57 electrostatic, a second Quad bashing by us this month, but we're not here to massage Hifi Royalty if we see it's wrong. The Quad will cope with this severe impedance dip as it was designed for, with much limiting compared to amps we prefer, odds are a 1965 Sony TA-1120 with it's complex protection circuit would just cut out, but other amps could be Damaged by this Bad Speaker as pre the Relay era the Protection Circuits wouldn't have coped too well. The review goes to say the Crossover has a worring 13 components to tame it all down, there is something seriously wrong if we see no circuit, but assume the Tweeters are in Parallel to get the huge Impedance dip, if they were in Series the volume wouldn't be right. RW says "yes it is a good speaker". We say it's the First of the 'Difficult Load' Speakers & should be all long since binned after they ruined good amplifiers. In the Jan 1971 issue a KEF Concerto speaker, usually a quality brand, is reviewed by Ralph West again & no doubt with his Quads. The midprice Chorale is a 2-way speaker & it's Impedance Curve is very good with barely going under 7 ohms. But the top range Concerto is that 3-way design we don't like. The Impedance Curve is not good, it dips just below 5 ohms at about 125Hz which is not such a problem, but between 500Hz & 1kHz at about 550Hz to 700Hz it has a nasty dip to about 2 ohms. The Quad with all it's Taming & designing for the ESL57 will cope, but an amp that's rated 4-8 ohm that can take 2 pairs of 8 ohms to make 4 ohms will struggle to play into 2 ohms. This isn't even mentioned as a problem this time. Be sure the KEF Concerto unless it was later updated, has trashed many amplifiers that can't cope with 2 ohms as their circuits are more honest. In Feb 1971 the B&W Model 70, a high model speaker that Sony licensed to sell under the Sony brand gets a review. This is a standard Bass Driver with an Electrostatic Treble driver. Once again by Ralph West & this time as we said above, he's using Quad amplifiers which are carefully designed to deal with the difficult ESL 57 Electrostatic & this too. £140 for either case design 'Standard' or 'Continental' if only 25w rated. Here the Impedance graph shows the speaker goes no lower than 8 ohm up to 4kHz but then a huge dip to 1.5 ohms at 14kHz which amplifiers less tamed would likely have difficulty with. Ralph West reveals he uses the Quad II/22 valve amp which is nice but very tamed. Then he uses Quad 303 power amp possibly with the II or 33 preamp, Rogers Ravensbourne & Goodmans Maxamp, neither of which we've had if had the cheaper Ravensbrook in the early 1990s & thought it poor as did the Ravenbrook receiver. The text explains there's not much going on above 4kHz which on some tamed amps is probably true, but they unwisely say amplifier overload is unlikely to occur, but in 2019 using CD & Digital TV Sound this will cause a problem. We've played a few amps "as original" on the speakers & do find even ones we rare highly once upgraded are often weak on treble. Weak amps might not get into trouble on 'difficult' speakers but even using a 50w amp on 25w speakers is possible with care & maybe amp failure has been blamed wrongly, unaware of the bad impedance dip. Verdict: Check out the Impedance Curves of any speaker to be sure it matches for Impedance. Tannoy 15" Golds are 8 ohm with 5 ohm nominal, but be careful of any speaker that dips under 4 ohm & best to avoid any that dip below 2 ohms.


Snake Oil Sellers? The Murky World of 'High End' Mains Cables.
We always find this amusing, these highly priced Mains Filters are fooling many into thinking they are worth having. One ebay seller does his best to sell his, but why doesn't he want it now? "This is a Clearer Audio Copperline 6 Socket Hub + Silverline 16am one meter cable. These are still current models and the cost new today is over £700. It is considered by users to be a Russ Andrews beat." For those into Hifi from reading the Hifi Mags, certain names crop up that "Fill A Need" but others will question as they did the "Green Pen" 1980s-1990s Urban Myth for putting on the edge of a CD to 'make it sound better'. The Mains Cables we've written on before, all any fancy cable does is use the LCR effect with Inductance (L), Capacitance (C) & Resistance (R) to be a Mains Filter. These "Wondered" reviews are using Modern Hifi that has poor power supplies compared to earlier years & any tidying of RF Hash will appear to give the 'Magical Improvement'. To look at their description of the Plug Sockets & cable is this..."Copperline Hub Description: Full star-wiring with Copper-line Power Cable; Wandsworth unswitched sockets; Three channel "Gatekeeper Surge Protection" with LED indicator; 3 x Super Suppressors provides unrestrictive passive filtering; Furutech FI-UK Gold Mains Plug as standard; Ideal for use with our Copper-line and Silver-line Power Cables. Silverline Cable Description: 6N Silver-plated OCC Copper (99.9999%) conductors for exceptional performance; Five layer silver-copper active sandwich shielding system for superb noise rejection; CL3 PVC insulation for safety; Super Suppressors remove mains noise; 90 hour fully constructed burn in as standard." It's just a glorified Mains Suppressor using Capacitors between L, N & E, the Surge Protection is as in any £6 mains plug block likely adding in the blue MOV discs like you see inside TVs. They add in ridiculous things like Gold Plated Plugs, this will wear off fast & look inside House Sockets to see they are just copper or brass fittings on a small part of the plug pin. Silver Plated Cables are another pointless idea, it's 50Hz Mains that goes into your Amplifier via Copper wires in the Transformer. Their Sandwich Shielding is just more LCR construction. To us it's worthless & we'd have no use for it. RF can be dealt with with £3 Ferrites as blogged before. We just use 5A mains cable from a big reel, copper stranded wire as you need nothing better. The Reviews by users are all very deluded, are they actually real people, they may or may not hear any difference but it's the wonder-Cure for All Ills. Rubbish says us. Our TiVo was picking up picture distortion, the Coax Cables from outside had no Ferrites so to Add one for Tv & one for Broadband did sort the problem & the TV Picture watching Live TV was slightly crisper. All so true that there is a huge amount of RF around these days, but the £3 Ferrites will solve your issues. The excessive mains filtering is a joke really, Mains is 50Hz or 60Hz, the RF noise is far higher frequency. The old idea of a Mains Choke the 1965 Sansui TR-707A receiver uses as this reduces a lot of RF, but generally if there is an issue the £3 Ferrite you clip on the cable will sort it. The £700 cable & plug has one bid of £90 on it which will be someone believing the hype. If your Hifi Sounds Bad, it needs a lot more than a fancy Mains Cable that likely only sounds better as you want it to, but if it was unplugged with you unaware, you'd not notice for weeks. The seller with the Clearline appears to have got £230 Winning Bid but "strangely" it's Up for Sale again "my second one" if the blue triangle sticker has the same scrape on it. There is a lot of this 'fake bidding' going on, to try to catch a gullible bidder & they are always this obvious.


My Amplifier Makes A Thump Noise On Turn On.

This is quite normal on Pre-Relay era amps & even some Relays make a click on turning on & off. For Earlier Amps, to hear a Bassy Thump we think is reassuring as the amp has power, the 1967 Sansui 400 does this now upgraded if as original on lower spec it made a lesser noise. Some amps physically thump too, our last 36" Panasonic CRT TV did that, this we've seen called "Pole Reversal" if looking online doesn't find that term, it's just the 240v Sine Wave hitting the Transformer & pulling high initial current. After the thump noise, the initial currents & voltages settle after a few seconds to a minute. Some amps like the 1966 Akai AA-7000 turn on with a loud "boing", ours we had we upgraded to stop that as it's to do with the original design, it then takes a few seconds to settle the voltages & the background noise then suddenly appears meaning it's ready to play, if this shows on Headphones it won't on 95dB Speakers. The Hifi Mags of the pre Relay era, ie 1967-72 had people questioning why it makes this noise. The replies even by the Hifi Names back then mostly said "we don't know" but sheepishly agreed it's not a problem. Go turn on a big Marshall Valve Amp Speaker Stack or hear them do it on TV, it makes that meaty Bassy thump as the amp has power & plays very loud. Later amps or lower spec amps can be quiet on turn on if can make a small noise a few seconds after turn on as voltages are ready. Sony amps are always quiet on turn on. The 185w Marantz 2385 has a "soft start" which involves 2 relays & a small limiting resistor direct on mains. If the amp makes a loud crack noise that is much louder than typical TV-listening then you could have a problem or just a bad power switch or switch snubbers. We had one amp we upgraded as any amp would upgrade, to be a selling amp not an experimental amp & the thing made awful thumps on the Relay. No fault, but the design wasn't very good & to not be able to upgrade it spoiled the point of buying what appear decent amps to upgrade. Another highly rated amp made a bad click noise on turn-off that took some searching to see why but again resulted in the amp being less upgraded to be able to sell it as what a buyer would be happy with. The low confident-sounding bump on turning the amp on is fine, it's not very loud in real terms if one reader says it scared the Cat. Earplugs for the Cat then.


Volume Controls: Why Are They Widely Varying Values?
Transistor Amps.
Some amps like the 1965 Sony TA-1120 have a very low 10K ohm volume potentiometer, the Sony TA-2000F preamp & 1967 Sony TA-1120A have a 250K one. 1965 Sansui TR-707A has a 125K one, 1967 Sansui 400 has 250K. Marantz 2330B has 50K if the Marantz 2385 appears to have a 20K one, if marked 20K/250K as it has 4 stages. In Volume Controls like 'Alps Blue' they have a Logarithmic Taper & are marked "A" if Linear Pots are marked "B" & also there is a Linear Balance version with only half the taper that's called the Latching version with the mid click. Some older ones in amps mark Log as 'B'. Volume is always the Log version & Tone usually the Lin version if some designs use Log. The Volume Control is one end the Maximum Volume from the Preamp or Inputs stage, the other end is Ground & the middle is the Output as it wipes the resistance track. The Volume Pot value is apparently irrelevant, Yamaha CR-2020 gets loud quickly & has 50K, Yamaha CR-200 similarly loud has 250K so the value doesn't match how quick it gets loud on rotating volume, it's just a potential divider. Yamaha CA-1000 & CR-1000 have 100K, if CA-1000 tone are 10K Treble & 25K Bass. Similarly on Tone Controls the 100K ones as the Sansui TR707A & 400 or the 50K of the Sony TA-1150. Does this explain Speaker Matching is down to Volume Control resistance? Sadly not as the Sansui AU-G90X with 100K Tone & Volume didn't match the 1967 Speakers. The amps with 250K are showing more confidence in their design as the higher value could bring up RF noise, but not necessarily the most expensive to see the Yamaha CR-200 is their lowest model with 250K volume if based on an older design. Sneaky Double Volume Controls. The Marantz 2385 with 20K volume has Loudness but as with the it actually has Two Volume controls in one with the other being 250K Volume for another stage to avoid background hiss. The circuit hides this by not labelling things too clearly. The Yamaha CR-2020 has the 50K Volume control is after the Inputs & before the Tone, but the Tone & Filter stages create hiss so they 'hide' a 5K one after the Balance control as the dotted line reveals, to stop the Preamp Hiss. The Marantz 2385 does similar, hard to follow, so look at the similar Marantz 2500 schematic which shows the Filter Amp gets the second Volume control after it. The Yamaha CA-1000 appears to have this too, but it's just the Volume & Balance on one control, the CR-2020 has 6 parts on the volume. All variants of design, if generally many other factors influence the sound, from soft & wallowy to glass-cutting treble of the 1980s. The Quad 33 preamp from 1968 has very low values to help further match to their ESL 57 Electostatic, the RV1-2 is 50K Volume, RV3-6 is 10K Treble, RV4-7 is 47K Bass & RV8-9 is 25K Slope with RV5 is 1K Balance slider. Valve amps are typically 500K or on older ones as high as 1 Megohm (1000K) if impedance is different to Transistors. The 1965 Rogers HG88 III that sounds great rebuilt & upgraded as we did one only very recently has a clean open sound. Volume is 250K Log, Bass is 1 Meg Lin & Treble is 500K Lin with 250K Lin Balance as is the Cadet III. Our 1979 Luxman LX33 has Volume 250K, Bass 1 Meg & Treble 250K with 250K Balance. The 2000 EAR Yoshino has a 50K volume that is not typical. Trio WX-400U has Volume, Bass, Treble & Balance all 1 Meg.


Testing Amps to the "Guitar, Drum & Bass" BBC TV Show.
TV sound is a good test on Speakers as it's Modern TV shows often with the big THX type Bass & this show with Reggae Bass plus 'Live' Bass Guitar as they demonstrate. Hear the 'Chic' Guitar Bass Lines & then mixed into their rather Bland Disco Hits. The TV show doesn't really go into the Sub Bass like some TV shows do, to not really hear the under 40Hz stomach-wobbling Bass. Playing it louder than usual TV sound but not so loud you can't hear yourself it reveals the wattage needed is more than the 20w of the Sansui 400 that does Bass very well but the extra volume isn't for it even on 95dB speakers & we'd not expect it. The Sansui TR-707A rated 18w but that is 18w into 15 ohms which is about 30w into 8 ohms. The TR-707A does Bass extremely well & our recapped & upgraded one is certainly one of the best sounding amps we've heard, if the Germanium hiss was noticeable. Further amps tested reveal some amps don't have such great preamps, the Yamaha CA-1000 had the Bass nice if the rest wasn't quite what the TR-707A could deliver. Our redesigned Sony TA-1140 sounded extremely good, they had to dumb it down purposely with some poor design that took ages to redesign. The TA-1140 using the TA-3200F 100w power amp didn't sound that much different if the 100w power amp instead of the 40w TA-1140 one obvious power increase & confidence to the sound, if the Sony TA-2000F preamp with those FETs isn't in the league of the excellent power amp. To redesign FETs to Transistors is a bit difficult on the TA-2000F if it's a challenge that's worth trying. Beyond Sony in 1970-71 very few amps used FETs in the preamp, the 1977 NAD 300 did & it was a disappointing amp. The 1979 Trio-Kenwood Model 500 range uses FETs so we decided to not try that. But back to the Bass Test, a 30w amp appears to be the minimum to get a 'Party' sound from, 15w-20w is fine for TV & Everyday listening. But interestingly over 30w with the amps mentioned, Bass sounded much the same beyond testing for the highest volume which we didn't test. 40w Sony vs 100w Sony sounded more open but Bass with both amps with our Upgrades was the same. The 30w Sansui TR-707A has a remarkable sound for a 1965 amp & in comparison the 1971 Sony TA-1140 with our redesign added a slightly firmer sound balance as the Damping Factor will differ, if neither amp has this shown on the Specifications, we'd estimate TR-707A is a 15 & the TA-1140 is about a 40 Damping Factor, just by the sound & knowing the Sansui 3000(A) is DF of 15.


Playing Amplifiers Loud Isn't Easy.

Of course the louder you play an amp you may think the less important the actual Sound Quality is as the Room will put in so many reflections at High Volume that crisp sweet sound isn't really heard. The Quality of the amp needs to be good regardless of power to not flatten out or sound harsh up loud is where many amps fail so sound pretty awful, the low-spec mid 1970s Pioneer SX-850 sound where the designs were penny pinched to be £100 less than competing amps. Most Amps of High Power are in the mid 1970s Cost Cutting Era so sadly are pretty lousy sounding Turned Up Loud as they just flatten out for low spec even at 80w, current limiting & dumbing down which is 'built-in' to get you to go buy something more expensive, they can't have you getting the Best Sounding Amp from a 40w one can they? But so many factors determine how good the amp will sound loud, we could hear the 20w Sansui 400 not being able to cope on Loud Bass as it was heard to flatten when other higher power amps played the Bass correctly. It's 20w, it's not for cranking up loud, it's more about sweet detailed sound as we upgraded it to be. All the Fun of comparing Amps using the same segments of the TV show, some amps play the Stereo wider than others for varying design features. We want amps that can do Quiet nicely as well as Kick Out on the Bass turned up louder, it's why we upgrade as we want it all in one amp, if it's actually rare to get 'all' from one amp even upgraded, one can sound awesome at 20w but not have the 100w power. Also in testing in the Blog above, using two amps with Doubled-Parallel Outputs the sound up louder didn't really seem better from those amps, we didn't try the Marantz 2385 with 185w for Triple Outputs as the Tannoys are 50w rated. It just tells that a lot of "gimmicks" in Hifi Design don't really give what you think they should, other factors are what makes the Best Sound. Played Loud the amp needs to keep in control, the midrange suffers the most on cheaped-out designs. When it's designed well or unfortunately for readers with disappointing amps, this means upgraded properly, again the Manufacturers are priced to the Penny & don't want you having the Best. Some 100w amps aren't as loud as you'd think & some 15w-20w amps are a lot louder than they should be, it's all down to the design. Valve Amps sound better as long as the design is good as there are less amplifying stages & with transistors this can be done similarly. The Yamaha CR-200 has a simple 1969 styled design & sounds much fresher than all the higher models, but it's only 15w. The Game of "Current Limiting" is about Design & it takes skill to understand that, you'll find Current Limiting mentioned but it's several factors all spoiling the sound together, not just one thing. If you work it out & just try to change one thing, be sure the rest of the design won't cope well & you get nasty problems like Instability & Flattening of Sound, which is why most only Recap to try to keep safe.


1965 Sansui TR-707A: Hearing It As Near To Original As Is Safe To.

As of typing, we have two of this great amp, one is ours & the other a customer got on seeing us raving about it. Both amps bought from USA were sold at a cheap price. From testing it, we understand why. On the Customer's one from knowing what ages most on rebuilding our one, we recapped the Power supply & Power amp but we left the Input-Phono board & Tone as original. The Sound using Aux is perhaps revealing why this wonderful amp is not yet appreciated. Bass is very weak, like having Bass Tone turned right down & it's a bit rough also. FM Tuner with Tone gain sounded better if the Tuner does have de-emphasis unlike our Audio test tracks. This Amp Upgrades to be one of the Best Ever, but clearly as Near-Original it's nothing special so really hides the quality of sound only brought out by our recap-upgrading & the other stages done will have it sounding better if the weak preamp. Actually quite a few of the 1965-67 amps don't sound so great as original but they upgrade really well, the build quality is there if 1965-67 is really early in the Transistor scene, so perhaps those buying these & playing it 'raw' wonder what the fuss is about. It's in The Upgrade where the best sound is. You don't expect a 1950 car to be it's best as original with drum brakes & other aged but working stages. It's like amplifiers too. Some amps like the TR-707A are beautifully built but the limits of the age & era plus the age-old issue of "Not Wanting To Give Them The Good Stuff Yet" as in 'Back To The Future' means many amps are sold as "Nothing Special" from dumbing down but hide a great design with our Upgrading-Rebuilding bringing it out. We heard from one buyer the JVC-Nivico MCA-104Z which is the amp version of their 1967 receivers, he said it had No Bass if otherwise was a nice sounding amp, the buyer has two of our amps already and as they said they are "Addicted To The Upgraded Sound". So are we & we continue to push further with upgrading, losing the poor preamp issue on the Sony TA-1140 & are trying to do similar with the Yamaha CA-1000 which has an awful preamp especially the Filter amp. It takes absolutely ages to redesign these stages & test they are good, but "What else Is There" after having tried so many amps now? Redesign the ones that seem to be well worthwhile past the crappy stage(s). The sansui TR-707A upgrades to souns awesome, if those Germaniums are still a bit hissy. so to try to Go Silicon & expect problems, but the great looking & great sounding TR-707A is worth it. A rebuild on this 54 year old amp is a big job, you can buy one cheaply perhaps still, but the rebuild costs are on the higher side. On the basis of someone just recapping like-for-like on the TR-707A if they would tackle such an early complex amp, the amp still wouldn't sound so good as it's still on the limited original design. Seeing one guy recapping a Yamaha CR-400 on a social media site as we have one here to do, they recap it all nicely, but still as like-for-like. As with the Car Shows, the Upgrades & Rebuilds are what makes Old Cars exciting, as well as nice paint jobs. Upgrading is far from easy & untold problems can be found for trying to be clever to make it better, the truth is you'll reveal weaknesses that if not fully upgraded will make the amp sound... worse. So What To Do? Learn skills.


Want To Be A Vintage Hi-Fi Tech?

The Vintage Hifi Scene has certainly grown a lot since we started this Hifi website initially as just one page about Vintage Record Players. There are Hifi Forums, the very useful Hifi Manuals sites like 'Hifi Engine' & others, but still really not any doing what we do. Recapping Like-For-Like is growing & be sure even this can bring problems to solve which is why some won't even recap but would rather rake in cash for repeat 'Repairs' instead of just rebuild amps over 40 years old, that's 1979. The articles we write are us having worked out what the Books & Magazines never told, some Blogs are us finding out about something & writing it as it'll interest others. Have we influenced the Vintage Hi-Fi Scene more than anyone else, you decide. But What Can You Do to get into the Vintage Hifi Game? A family member of ours currently teaches their skills based on their progress from us suggesting ideas to start them on it & now to many others in a fashion-related scene where there is a lot of interest, but it's quite a narrow skill. The Game of Vintage Hifi needs so much learning & time invested as well as many amplifiers to 'try' on & mess up in your progress. To go to a College to learn Electronics only really teaches theory, much of it means nothing without any hands-on experience, the teaching we had in the early 1990s may get you a Certificate but hardly any Practical Experience. What we do now is based on what we've tried over many years & having the nerve to try & ignore the accepted ideas & rigid opinions of "The Grey Old Men" in tech. You can start by learning how to repair Electronics, but today Repair is not like it was in 1990 as today things last 2 years & you buy a new 'better' one. Today's Repair Tech probably knows very little but knows how to order a plug-in board & how to fit it. So you accept Hifi repairs is a dying art, but all these Vintage Hifi items people like & want working right. we get asked to fix 'everyday' electronics like Music Centres, Tape & CD if this is more trouble than it's worth & the customer expects a cheap job unaware of how much work it is. On doing our BTec the nearest one to Hifi was TV & Video Repairs, the tutor said how boring the job was to us, if not to the whole class. Repairs are boring, frustrating, time wasters & ultimately you can get caught by unfindable parts. The general idea of the TV Repair Tech is a older weary man with no personality or attitude, because he only knows formal ideas rather than dare to think or question. But you need to learn the scene doing the crappy jobs to realise why you should never touch them again. To try to explain by email how a customer can sort an issue they have is impossible, they should just send it to us instead of weeks of them thinking they can do it & we'd solve it in 30 mins. We get amps that we aren't happy with, the 1966 Rotel 100AMP up for sale isn't very good as no manuals & it's useable as stated, but far from what we'd hope it would be, this shows how important good Service Manuals are if we have sorted several amps with no manuals from working the circuits out. the Rotel wasn't even working right with bad resistors so what do you do? Wasting your time is unfortunately not rare in Vintage Hifi as it brings up weaknesses in the amp design, problems that are 'unfindable' result in whole stages needing rebuilding just as it's quicker to do. Going into redesigning stages that are poor can take absolutely ages, we did this with the Sony TA-1140 & the results were well worth it, if the Yamaha CA-1000 has a poor preamp & getting that right on awkward boards is a real challenge, but that is advanced stuff & might not work so well unless you get brutal with it. So Start Small, get Hifi in for Repair once you are to a standard where you aren't just going to trash their amp or give it back not working as we've known with Repair shops. We see those on ebay apparently selling 'upgraded' amps but never any photos of the amp insides to show what they did & the price is very low showing a lack of confidence in what they've done. It takes years to learn how to do the more difficult amps, it takes confidence in your work & a certain daring to try things to get progress. To do a lot of work to an amp & have it play right first time & similar with other amps is showing you're good. Vintage Hifi is rewarding for getting Old Wrecks going again, hearing great amps & then it Rewards for others seeing what you do & trusting you with their Amps to work on. But it takes Years to get to that Standard.


March 2019 Blog

ICs: Should You Get Involved? Snog, Marry Or Avoid?

The Thorny Question of ICs. We've tried plenty over the years if not many on this site, only the 1986 Sony TA-F550ES with an IC power amp driver, 1977 Marantz 2385 with IC Tone-Preamp & the 1973 Sony TA-1150 with IC Phono & Tone-Preamp. Start with the good: The TA-1150 Tone IC we tested similarly to how we did the Marantz 4070 in a blog earlier & it coped as well or better than the Transistor design in the 4070. this IC is long obsolete if it a basic design with 2 channels in one IC. With upgrades we did on the amp & to be sure the Voltages were matched, it actually sounded great as the rest of the Preamp was uncomplicated. The Marantz 2385 tone stage using the thin in-line ICs wasn't so successful, at Max Tone it didn't have enough Voltage to give a full output as the TA-1150 could, perhaps it needs better design? But to use Max Tone at Lower Levels will keep that being worthwhile. The 1986 Sony TAF-550ES we thought was the Most Boring Amp we'd ever heard on getting one in 2011. It had a large STK IC block for the Power Amp if Transistor Drivers. We also had the 1986 Pioneer M90/C90 Pre-Power 200w pair, the Preamp was stuffed with ICs & unshielded ribbon cable & the Power Amp used an IC for the Bias stage. We just sold it on as it was abandoned & not in good condition, we couldn't be bothered with it. So that's what you get, some are good, some are bad. But the Main Point is to Keep Or Avoid. We get amps to upgrade for our interest so what we get is what we want to try or trust. AVOID: Anything with Power Amp ICs of the multi pin STK type we'd never even bother with. Parts obsolete like V-FETs & many other Custom Transistors as well as MOSFETs that are more a fashion thing than better than the 1960s TO3 transistors. The risk of damaging Unfindable ICs or needing to replace ones already damages is usually 'Unobtainable' so ones we avoid. You can't rebuilt the IC as transistors as there is no space, the amp is sadly parts or disposable junk as there is nothing that can be done. Some semi-ICs like Darlington Transistors like B&O use are still buyable & that is where the lines get blurred, if you can still buy spares for the IC at reasonable then it's worth having regardless of criticisms of IC sound quality. For ones we've looked at, the Power Amp ICs can be £40-£75 so not worth buying amps with these unless you realise they are use until they fail. KEEP: Anything with Phono or Preamp ICs including Double FETs & Double Transistors that look like ICs but are just 2 transistors in one case, plus Op-Amps, those 8 legged "75p new" ICs to us means "it'll sound lousy" because it always does, if sometimes for for weak design than the IC. Early ICs like the JVC 5040 & Dokorder amp used are a different thing as are the thin in-line ICs, if sound depends on design. These are highly unlikely to get damaged beyond misuse so even obsolete ones like the Sony TA-1150, what's going to damage them? Nothing will is the typical answer. Again the exceptions, the 1971 Nikko TRM-1200 amplifier has ICs on the Phono stage, ones that always fail as we found on getting the amp. these failed early on in the life of the amp & the part fast went obsolete, if there is an equivalent circuit we built with Transistors & Resistors that worked fine. This is rare in a few ways if to have an equivalent circuit is the only one we know of. So the "Marry" & "Avoid" is dealt with, the "Snog" are the ones you Try to see what the ICs Sound like. Low Priced gear late 1970s to mid-late 1980s with ICs & Op-Amps means it'll always sound awful for the heavy costcutting. The thing is with ICs is today huge amounts of research are put into them, the budget IC riddled item of today with 2-5 years lifespan will usually sound better than the early 1980s IC amps. They've learnt the Class B circuits over time & how to tame the designs to sound acceptable if they are far from being lab spec "Hi-Fi", a £200 Amazon amp is not Hifi if it's still bought as it's all they want, Mass Market Goods. Amps like the 1980 Yamaha range CR-2040 etc we had a look at on the "Other Amps" page & were not pleased to see such heavy reliance on ICs at every stage & we'd never buy one as it's worthless for us to try to do anything with excess ICs. Some amps with ICs go 'flat' too soon & to hear them at high volume is an amusing mess showing how IC power amps are very low spec. We'd avoid Any IC Power Amp amps & unless they are cheap, even some Monster Receivers have them as Blogged before, these sort of amps are best avoided as once they fail, you'll likely never find the IC blocks unless at £80-£150 each as some sellers try to offer them.


Remembering Earlier Amps Plus The Intense Upgrading Manner.
Getting a 1967 National-Panasonic SA-65 to rebuild, the "Nat-Pan" as the buyer of ours in early 2015 thought of it plus the 1966-68 Sansui 3000(A) reveals a turning point. Early Spring 2015 we got a second Pioneer SA-9500 Mk I 80w amplifier from 1975. We'd upgraded one before & done quite a lot with it if it didn't match our Tannoys so well so sold it on. The Second SA-9500 arrived with the fascia with a dent on it & an insurance payout after a tough battle. "You're Free, we can do as we wish with you..." was the idea so to do all we wanted to try to better the amp if in 2019 we'd go even further with it, into the realms of 'too big a job to charge a customer' but this is reasearch. The SA-9500 unlike some amps we've had liked all we did & upgraded more than any amp before. 'This Is Good' we think & to do these tests using test gear to see they are good shows they are. Seeing now the SA-65 was sold just a few months before this as was the Sansui 3000A, shows the ideas from these amps plus the Sony STR-6120 that we got back fairly recently & had to rebuild it to be reliable. The Pioneer SA-9500 is a quality amp & upgrades well so other amps we've had & still keep as references get these Upgrading ideas further & further, just to find the Absolute Hifi. There are certain design features that mean an amp will upgrade better if to remember not everyone likes the PA sound at home. Hifi is a Domestic Scene, PA sound is a Studio Sound if some amps claim to be 'Studio Reference Quality' but really are far from it. PA sound can be very loud at times, such as on TV with normal soundtrack & then someone shouts & you jump to turn it down as it's louder than real life, the TV Monitor speakers aren't as Wide Range & Dynamic as Our amps. We said we get Intense on Upgrading, but that's not with Customer's Amps at all, those aren't for experimenting on, though you will get ideas from this Research into Upgrades as Standard once they are proven to be reliable & test well. Some Research Amps do get sold & to see the work and parts put in to only price it at a certain price for it to actually sell reveals the market is still growing on Rebuilt-Upgraded Hifi. One amp recently inspired us to go further with another amp for hearing that sound amid similar specs, so why not try to get that sound from this other amp. It worked & actually betters the 'best' by the same maker sold at the same time. Putting mid 1960s ideas into early-mid 1970s amps usually isn't possible.


High & Low Filter Controls On Amplifiers Are Often Very Poor.
You don't use them, us neither, so why bother writing about them? High Filter is a Low Pass Filter as it cuts the high frequencies & allows the lower frequencies through. Low Filter is a High Pass Filter as it cuts bass-rumble if your Turntable is a noisy one. But in Amplifiers, these are often very poor designs with ridiculoursly complex "Filter Amps" that clearly haven't got the First Idea how to do this right with it sounding good & giving enough cut to be worthwhile. Filter amps with 3 transistors, sound in & sound out is at the same level if mangled. Filter Amps with Large Resistors for the Signal to pass through do the Audio no good either. There is a "Perfect" High & Low Filter in the 1965 Sansui TR-707A. Low Filter goes through a limiting capacitor if the amp design is quite different so it will have Impedance differences if more typical amps can do this way also. High Filter is equally impressive, no limiting or tamed circuit, this simply uses a small value capacitor in an extra NFB stage to reduce Treble. Both Filters switched out impact the circuit in no way at all. No Limiting, no extra Transistors, just done intelligently. This is rare to see in any amp for either High or Low Filter. 1966 Sansui 500A filter was hopeless in comparison, the TR-707A designer is a Genius, the lousy 500A just disables the Gain half of Bass & Treble to fool you into thinking it does something in a Shop Demo with Tone added to deceive. the Valved Sansui 500A is a very mediocre Valve Receiver, almost like they didn't care about Valves by then, but the 1000(A) valve amp is an awkward one too.


Vintage Amplifiers With Silent Backgrounds?

This depends entirely on the Amp itself & can vary within brands. The 1965-67 ones can have a noticeable noise. On 95dB speakers this means you'll hear a low level hum & hiss just because of the early age. Some amplifiers can physically hum from the Transformer too & this was mentioned in HFN/RR into at least 1971. The Best Sony Amps such as 1968 Sony STR-6120 & 1965-67 TA-1120(A) have a very low SNR & the manuals tell you the 6120 on Aux has 90dB as "A" weighted whatever that is to alter actual readings, but the 6120 is as good as silent on 95dB speakers in the dead of night. The TA-1120 is remarkable for how early it is to have the same 90dB reading. The 1971 TA-1140 is even better at 110dB. Not all Sony are this quality, the STR-6850 EU type receiver wasn't the build quality of the 1969 STR-6150. Germanium Amps can be hissy if the 1966 Akai AA5000 surprisingly is very quiet & to estimate it's at least 75dB. The 1966 Akai AA7000 is not as quiet. The SNR noise level depends on the design more than the design type, the Transformer Coupled or Germanium amps can be noisier as they are earlier, if it depends on design. The 1966 Fisher 600-T is all Germaniums if well designed to get the best from the Germaniums with a very low SNR of at least 85dB. The 1965 Sansui TR-707A is mostly Germaniums but despite the great sound the SNR is pretty poor to the point it's distracting on 95dB speakers if we halved the hiss noise on one we did for a customer, the 707 manual oddly says Noise is "less than 70dB" which sounded more like 50dB on ours. To redo a Germanium Amp as Silicon is possible, but be sure it'll not silence it & there is a good chance of getting odd noises that need lots to sort, so this we'd only try on our amp & knowing the 1966 Rotel 100AMP didn't do very good if maybe we'll try more another time. An amp that is Hiss & Hum-Free with no Mechanical Vibration on pre 1970 amps is not the general standard, but the far nicer sound for a little noise is the trade in. Actually on removing all the dumbing down from the 2007 Marantz PM6002 it revealed some hiss just like any amp would do, it was only 87dB SNR as on the manuals & without their dumbing down it was more hissy than a 1970s Yamaha, progress there is none in Analog Hifi as it was just about perfected in 1965 by the Sony TA-1120 to get 90dB SNR that early. The 1973 Sony TA-1140 having 110dB SNR is very impressive, the TA-1150 doesn't mention SNR if the 1975 TA-3650 has the 110dB SNR. The Most Boring Sony we've heard, the 90w Sony TA-F550ES has Damping Factor of 100, THD of 0.003% only puts Noise as 0.9µV which is meaningless if also puts 108dB SNR on Aux etc. On MM Phono it has 77dB noise, MC is 95dB which makes us wonder why people bother with MM cartridges, the 1969 Trio-Kenwood with a MM stage was very hissy with 45dB as HFN reviewed it, clearly of little use with that much noise. Later Amps do 'cheat' to get better SNR by putting 2-Stage Volume Controls, some have an unexplained second one after a noisy stage like Tone or Filter, to avoid having to design the preamp to have Volume after all stages as designing a Preamp with Max Tone Level not clipping is far from easy. Most Amps put the Volume after the selectors & tame the preamp not to hiss so much which lessens the sound.


1977 Sony TA-F5A Amplifier: Any Good?
To try to find other good amps of this later era into the 1980s brings amps like this that look good, solidly made with some Luxman influence & Yamaha meters, but to then see the inside Photo the seller with one at £275 shows. 70w Amp for £275 today seems a bargain, but is it? Pulse Power Supply, much like what is in Computers etc of today, lots f circuitry that's "better" than a reliable Transformer is one we've not liked on seeing how Dangerous these earlier ones ate as with that Technics 1978 pre-power. To ignore that for the moment to see what else it has, oh it has ICs on the Power Amp Board with the usual 'rubbish' you see in 1980-s amps in a complex IC, interesting to see this is where it all started, if the Sony TA-F5 is the more complex version, no manuals to find. In one IC per channel it 'needs' 2 Regulators, 2 Differentials, Current Mirror & Constant Current Supply as two separate parts, Bias Circuit & Class B driver. Then in Transistors the bemusing Voltage Slicer & Stopper Diodes and Cascode Amp plus Current Limiter. why am amp needs all this Limiting & Controlling is a mystery to us, it sounds awful & the only 'Good' of it is to get pointless THD specs for the Hifi mags to say how much better it all is. Sony TA-F5A amp is a good looker of the era but filled with junk if it's not unlike Class B IC circuitry of today. The Seller says they have too many amps, this has spend much of it's time in the box & now they sell it sort of tells they don't like the sound of it so off it goes. The TVK site likes these sort of amps as they are more modern, but we see the Volume Control with an unshielded Ribbon Cable. Looking at the Preamp, the 4 Gang Volume Control is like ones we blogged above on, it has a Volume Control before the IC preamp & one after to keep the Hiss down, again to get the High Specs, 100k first one & 10k second one. All as far from the Hifi we like as could be. These later amps with several Class B stages & unnecessary Differentials are just Not Musical, they sound awful. Historically the Sony TA-F5A is Important as it shows where so many of the Ideas now used in Audio Gear & Power Supplies for TV & DVDs etc started. The Class B stages in ICs to use less power & create less heat. These Class B stages are on Computer Soundcards & they are designed to sound good with very low 105dB SNR Noise Floor, but if you try to play a Square Wave through the Soundcard & read it on an Oscilloscope, it shows the whole technology fails as the Square Waves are terrible. For Musical Pleasure, sadly the TA-F5A is one to avoid. Looking at our "Other Amps" page, we looked at this same amp in 2014 & thought the same...


A Nice Amp: 1972 Onkyo Integra 732 Amplifier.
To see an interesting amp but find no proper info is a shame. Beware the misleading power ratings. The 725 is in the HFYB as on our Amps page at 25w for £98 if clearly long before the brand was a mass market one. 1975-76 HFYB says the 732 is "56w max" if another source says it was reviewed in Apr 1972 if that's to be believed. Good looking Silver Face Amp, looks of good quality. The Top Cables connecting method suggest more 1975 as was used similarly by other brands, not a good look & the amp came with a black top cover with a clear window, so the ebay one in Hungary with warped walnut home-made case is what there is if you wanted one. Inside hard to tell if ICs in any stages if looks well built, but a bit of a gamble for no schematics. Actually HFE site has that 1972 review so to have a look. 59w 'beide canal' can mean 59w each channel, one channel played as per how other brands mislead, so likely it's 45w RMS both channels playing, as Trio KA-6000 is 58w misrated. The review shows Square Waves slanted as Bass will be limited, if it does test 59w, if all a bit guessing so 45w we'd consider is right. Another one for sale on a Vietnam site shows lots of inside pics, a bit random built if quality. Just too vague on the info, it's Made In Japan as another site says. The Hifi Info Sites have helped a lot with Manuals, if with this amp it's as vague guessing as it was in 2000 & we don't gamble that much with no manuals. The redone wood sides meaning the top lid is missing decides we leave it if to keep the pics if another turns up. Buying from countries like Hungary etc that you'd not consider for Hifi is actually fine, if the goods themselves can be a bit more aged & used, trade itself is reliable. ** Sept-Dec 1972 HFN/RR has ads for Onkyo. 25w RMS "725" is "70w max", the ad shows the 725 is "22w +22w one channel driven", meaning about 18w RMS both channels. Very confusing if the amp appears a good one sonically, "733" is 86w max so assume 25w RMS, if "732" is 56w max so assume about 14w RMS. Very misleading power ratings get people overspending thinking they are high power, the Sansui AU 999 is rated 180w in adverts at the time yet it's a 50w amp & fools appear to think it's worth £800+, see our Review of it. "433" Tuner & "M70P" turntable. Onkyo weren't good at selling their hifi or giving honest ratings so failed... 725 = 18w, 733 = 25w, 732 = 14w RMS both channels playing.


That's A Nice One Too: 1970 Luxman SQ202 Amplifier.
Inside rear cover of the July 1971 HFN/RR has this amp. Is it a receiver? No, the top row is lit wording for Button Input use. Not seen this one before. 80w+80w for £210 says the advert. Appears in the 1972-73 HFYB & by 1974 it's up to £267 which is for the high inflation then, if new range by 1975. One of those "we want one" amps if looking on ebay nothing & none sold in 3-6 months. Hifi Shark site shows one sold in Japan for £372 if the same one shows many times, to assume 'reserve not met' before 7 many others with higher & lower prices, the Japanese sellers are way overpricing, so assume £300 is about right for today. No Manuals easily found if usually these are the ones you need to buy the download. TVK site has it & they say what we thought, the first of the 'Classic' Luxman era after the rather basic earlier ones with lines of boards inside as the 1968 50w SQ1220 is. 70w RMS both channels is the real rating if still high for a 1970 amp. An Australian site shows them taking one apart & it looks well made inside & far from the basic early build style. Power Amp modules not unlike the 1975 Luxman L-100 which we found rather limited in space. The usual spec of the era does allow good upgrading though. Case has side wood posts as no full side cheeks or wood case. Certainly looks a good amp but yet again we are without Manuals as with the Onkyo blogged just above. Two interesting amps found on the same weekend, if to find ones to buy that are complete, the Onkyo lacks the top lid & the Luxman is a rare one.


April 2019 Blog

VirginMedia TiVo vs V6 Box.
We've had a 1TB Tivo Box for about 5 years, we were on the second box as it appears the Tuner doesn't last long & huge blocky distortion for a second ruining the picture is annoying. Try talk to VM & they are as bad as any other company now, they want to try to fix it or swap for the old 500GB box. You ring them up, they transfer you to the wrong department & the fight against people who don't understand English as well as the Call being dropped if on hold. Rubbish. Solution was to go to Account & see what upgrades you can get, a V6 1TB box with the 3.0 Hub for those who want to Watch TV from their Box on a Train etc, technology that will appeal to travellers, if likely 'TV To Go' is expensive & no interest to us. New 'Kit' as they call it arrives, not hard to plug in & be ready. Still based on the Tivo platform with no real differences beyond a better Remote Control. We're playing the Sony TA-2000F/3200F as blogged Pt 3 below & with the old Tivo the sound was a little loud on some amps if it was crisp & clear. The V6 box via the Optical Out appears to be about 5db quieter, it still sounds good but doesn't appear as upfront for being 5dB quieter. There is a 3.5mm Jack for audio out that we've yet to try. One thing you'll notice is the silly LED lights are way too bright especially if you see at night with no lights on, we just coloured them over with a Black Paint Pen to still see they are on but about 90% dimmer. Amazingly there are no settings to dim these lights, years ago VCRs etc used to purposely use dim lights to not show you had gear to catch unwanted attention, but VM clearly failed here. As for the picture, to have seen it do the glitch twice as of typing shows it's a VM issue in their system still, even adding Ferrites to the cables which did make the picture clearer, VM don't put any Ferrites surprisingly if their signal cables do need this. Interestingly it was found the Marantz 2385 that previously wasn't too great on the earlier TiVo box now sounded much better with the new V6 box, the 5dB reduction in level has brought more finesse to the V6 box despite the Sony pair having it sounding less impressive, but with the older Tivo it sounded better. Just shows how different Sound balance is, even from what you'd think is a standard digital output & we're still using our upgraded £10 DAC. Unfortunately BBC1 HD still records with the odd bit of picture distortion, three times in one 30 minute program, so it really is the VM system or a fault in the network or street box.


The Increasing Problem Of Bad Main Capacitors On Post-1977 Amps.
This we've blogged earlier about the 1977 Rotel RX-1603, the amp was likely stored in direct sunlight & dried the main Capacitor nearer the back. This time a 1985 Dual CV1460 amp sounded awful once recapped so to suspect Bad Caps & run it in for several hours which changed it's sound opinion from Average-Recommended to Very Good-Excellent. A huge jump in quality as the 1985 main caps were bad & not delivering the required voltage or current. So we take the old ones out & cut them open as pictured here. The caps are from 1985-87 so are 32-34 years old. First impression is they are still damp, not as wet as newer caps but not obviously bad. We probably 'reformed' them running them in for hours. You could probably use the amp, but you're living on borrowed time: The Caps Were Bad and are clearly well past their best if briefly "good" again. To get Bad Caps is either from letting them get hot from poor ventilation or possibly just not using for Decades. We've considered Main Capacitors still good in some amps into the 1970s with acceptable values, Yamaha, Luxman, Sony etc, but over the years we're seeing them start to fail more & a 1985 amp is a bit unexpected. A valve amp that gets daily use will have it's main capacitors losing quality after 10 years which matches the voltage-current-hours stats the capacitor makers give. Knowing that even a 1985 amp was bad means any Recap-Upgrade must include the Main Capacitors now. The big Yamaha CR-2020 with it's 2 non-standard size capacitors tucked away is probably the only ones that are still good. We have a 1973 Yamaha CA-1000 that was badly used with Class A & dried the amp out causing one main cap to leak, to match that size isn't possible now so we got 2 similar. The bad cap had leaked & was dry if not crusty & the other one away from the heatsinks was actually wet & good for years more use, but to cut it open to realise. Some of these big caps are £50-£80 to replace the pair just to buy inc VAT. For customers, to have them aware the big caps could need replacing is now required, if depending what the amp is like once seen & to at least try the rebuild-upgrade to see how the amp is.


Vintage Hi-Fi As Seen On TV: Phase Linear 400 Power Amplifier.
Good to see American Pickers Series 18 Episode 26 from 2018 have this amp featured plus a short Hifi section. Found in an eccentric guy's barns it's in useable grade, they haggle to $275 & value it at $550. All apparently without plugging it in or knowing if it works still. But to film them undo the case or hooking up to a Pre & Speakers wouldn't be good TV. The $550 value for a 210w Stereo Power Amp sounded a bit low, if actually Hifishark site shows that's a higher price & ones on ebay for $250 to $500. Be sure it'll need a full rebuild for the age, Mike himself says they make big money once "fully gone through" & way beyond just a quick service. Low price suggests it's an amp for the likes of us to get & rebuild, meaning that like 1965 Sony TA-1120 & 1977 Marantz 2385 they aren't that wanted simply as the rebuild is so high on these, if having done these & many more & having the 2385 on speakers currently, you certainly need to spend, but what you can get from them can be extremely good if realistically there aren't too many who will put £1500+ into an amplifier. Back to the PL 400, HFE site shows the range 200 with 105w & the big 700 with 340w are heavy hitters. What the preamps are isn't on HFE as only 1976 era earliest show when the power amp is 1970. What do you need 350w for? There are no 350w speakers, it's for driving multiple speaker rigs which were only 50w each at that time. PL 400 has a very high Damping Factor of 1000 which suggests it'll be a very dry & tight sound for PA work, rich Bass is not the thing as Heavy Damped amps damp the Bass. The Manual Shows the Rise Time is very fast at 1.7µ sec, we bettered that with the Sony TA-3200F upgraded & the Marantz 2385 upgraded was nearly that value. But it needs 1.7v to get full power so many preamps won't be loud enough so will not help the sound, Manual says 201w, big heatsink fins & the Schematic in the User Manual shows Tripled Output Transistors. The design has a lot of Diodes in it to keep it within itself, or to tame it which it admits to being stable into any load including electrostatics, 200w into a 50w speaker. Differential input after a high 10k signal limiter resistor isn't good, they are scared of it just as Sony were with the TA-2000(F) & 3200F pre-power. One on HFE says Diodes D1-2 get very hot, theirs needs repair then. Main caps are 5900µf 85v which are very high values for 1970 & will be huge items. Design looks tame, "rugged" design to put up with heavy use & not trash speakers. Ones on HFE using a 200w amp on 2011 era comments to use a 40 year old amp then, is way too risky. A type of amp that's not going to be what we'd like soundwise, wouldn't even trust a working one as a 1970 amp if rebuilt it will please some, but at 200w it's not an amp we'd go upgrading too much as it appears to need it's taming to get that scary 1000 Damping factor. We'd recommend it as a Collector's amp only, not one to use & that's why the prices are so low for a 200w amp, it's probably not very sophisticated & needs a full rebuild. The Phase Linear 700 with 345w into 8 ohms is worth a look. 0.01% THD & the 1000 Damping factor again shows the amp is overdesigned for specs & tamed if the fast rise time & Slew Rate of 11 volts per microsecond, if 350w is a way to climb. This time it has 5x Parallel Output Transistors with 9800µf capacitor value on ±100v HT. The Manual Bulletin tells of Transistors & equivalents if the SJ/MJ2741 are long obsolete & that other difficulties. Now you see why they are cheap, they're a Nightmare as too ahead of their time & lots of design changes through the runs. Does Mike still have his amp, those interested in these will consider them "leave it alone" as far more reliable ones in later years.


Is It Worth Spending To Rebuild An Amp?
We had a customer ask about rebuilding a 1970s Sony Receiver, the STR-7065A which is a rarer one as 65w receivers weren't selling in that difficult era. They paid £500 for it, a full recap-rebuild on all but Tuner will cost more than that. Is it Worth Spending The Money? On terms of you getting a 44 year old amp & risking failure, as of typing this April 2019 we are finding 1979 & 1986 amps are having bad main capacitors & the rest now being 40 & 33 years old really are getting old in terns of what you should trust using. Assuming you want an Amp to Use Everyday, then a rebuild giving upgrades & all-new critical parts is sensible. You are then confident to use an amp you should get easily 20 years use from, not that this is a Guarantee, it's from knowing amps & ourselves being cautious to even try old amps in original condition on speakers, we'd certainly not trust our Speakers with a 40 year old set of capacitors though we do try some once serviced & tested just to briefly see what they sound like as blogged. We know many just buy a 1970s-1980s amp & just use it, not Servicing or anything, their risk & be sure these aged amps get problems sooner or later. The idea of just Servicing amps over 30 years old is money wasted really as it needs recapping & for the huge benefits of recapping, get it recapped if it's a quality amp. We Service the Amp on Rebuilding it anyway. It's quicker & more cost-effective to Recap an Amp than just Service as the amp needs taking apart in both instances. Then the Financial Aspect, is it worth putting money into an Amplifier & hope to see it's worth the sum of buy & rebuild? The market on that is still growing as not many recap & as far as we know, no-one offers upgrades like we do. We get amps to sell just to have a range of rebuilt amps to sell, these range from starter amps to more sophisticated ones & we see the work we put into these amps isn't always realised in resell value, if the margin is getting smaller. If you like the amp & want to get years of reliable use, then get it Rebuilt & use it without worrying it'll fail. Upgrading To A Sensible Price-Results Level. We don't put high price upgrades into amps we'd sell at £500 & to rebuild one similarly would likely cost the same or more than our sell price, so it's a bit of a loss leader. With customer's amps, especially ones we know & have upgraded far further than what we'd offer as an upgraded, these are priced to give the Best Improvement at a Reasonable Price. The Marantz 2385 as a raw aged amp has a standard value if working, the rebuild in our one & subsequent upgrades has value way over the price we offer at, if we don't expect it to sell & leave it there to show we can do these Monster Receivers, currently it's on our Speakers. Whether the Amp is then fully worth your Buy Price plus Rebuild Price depending on amp is close to a price we'd sell one at, ie a £900 buy-in & job may yield a £750 amp currently. But you're Rebuilding to Keep not turn-over & in a few years prices will only get better, we see our 2014 prices as rather low now & a little shocked at 2011 ones. With Amplifiers, we've done enough to price Rebuilds to give you a good value rebuild without going into doing more marginal upgrades that we know don't show as much for the Money spent as the "Standard" Rebuild. Example a Rebuild can give over 100% improvement on a working amp, if spending the same amount then going further upgrading may only better it by 20% which isn't Cost Effective. Be Aware The Earlier Amps Pre 1970 require deep complicated rebuilds as so much is old, to rebuild amps like the 1965 Sony TA-1120 & 1966 Akai AA-7000 are expensive jobs as so much needs doing. Summary. The rebuild costs on some amps does put buyers off, to buy a decent £500 amp & expect a £200-£300 job just isn't realistic. We'd not recommend a high rebuild job on amps that wouldn't give good results. You'll find those who'll service or repair it cheaply, but we've heard of those doing this & later send the amp to us & we see what awful jobs have been done. To think "Who Understands These Amps Now?" The TV Repair type has no idea as Tech of Today is about swapping boards. Rebuilding Vintage Hifi Isn't Cheap & these amps are only getting older, 1979 is 40 years old in 2019. We do Specialist Work that very few do these days.
This section was written for the Upgrades page if worth repeating as a Blog.

BBC "The Repair Shop": Glossed Over Sentimentality?
This is back for a 20-show run this month. It's an interesting show, if they do overdo the sugary sentimentality a lot, much like "The Antiques Roadshow" goes more for a story than goods sometimes, plus the BBC agenda that is notiecable. The Repair Shop has some skilled craftspeople, the Clocks guy, the two Teddy Bear women, the leather working sister of the Clock guy & others. They get brought in items that the owner has contacted the show about & they do get a diverse selection. The thing people don't realise with Repairs that the show really doesn't tell enough about is Repairs are often far more complicated, they show problems they get but not the many hours work & problem solving. The person doing the Repair is always shown as being 'delighted' to work on it, be sure there is a lot of grumbling having to work on such badly damaged stuff as it can be a Nightmare to get nice again. Doing Hifi is similar, the customer wants it working right & looking good thinking it's not a big job to do, much as the above blog tells. This series so far had a knackered old Transistor Radio that they should have binned & looked on ebay for a much nicer one, instead the tech guy had huge problems with it & did get another radio to cobble bits out of, the Antenna was too far gone & no way to know how to fix it. They cobbled together a handle, made the tuner dial from random pieces if left the tatty case. Piece of junk that works, value just about nothing, looks rough but the old guy was in tears with it as often "it's all they had" & put such strong emotions into it. The thing with Repairs is the item matters to the person, but these TV shown ones would cost far too much to get repaired, that Radio could be a £300 job to get going yet it's of no value. Another was a 1950s clockwork car, insides not made of quality to last so the guy had to design & make new pieces which the show had look like a 10 minute job instead of likely several hours. The trouble with cheaper goods is they can often be poorly made with compromises, frustratingly poor design & manufacture. UK & EU Amplifiers can be a real pain for this poor quality build. The hours work, the problem solving & getting parts to get Old Amplifiers into Use-Daily is a huge job, we've spent years working things out to make it easy, but doing the Yamaha CR-800 preamp stage the day before, it'd overwhelm just about anyone, bad circuit manuals & highly complex cramped circuitry would put any tech off working on it. But to plan & control the random chaos into a workable job & have the ability to check it's right after can be done & be pleased to have solved it. To look at some amps & think "You Horrible Amp!" for bad design & construction is quite common, if it's to be able to do the work to give a good Finished Product is what "The Repair Shop" glosses over too much, not showing the time & skill involved. the guy with that tatty radio isn't aware of the work as it was done For Free for a TV show. In our upgrades, you're paying for Parts, Labour & years of having solved similar problems plus our Upgrades that give a reliable improvement. Twenty Episodes is the BBC wanting more shows if you can see the joy is wearing thin on some of their faces, being told another story, two were seen not looking very interested. Still, that oil soaked Bear, "know what a bin is for" we thought but they revived a very dead bear into an old friend again. But what would that cost to do away from the show?


You Want To Do Hifi Upgrades But With No Effort To Learn?
One idealistic person messaged us looking to be told of a Book that tells all of what we do so they can do what we do without putting any effort into it. No reply to that... There are No Books, there are No Websites that tell as much about Hifi as we do. We never tell of the technical side as that is a person's Trade. You need to put 25 years & 200+ amps behind you, plus daring to try things well outside 'the box' to progress, before you'll understand what we do. Plus have "The Ear" to understand Good Sound that is only found in our Upgraded Amps to have a Reference to compare to. People are lazy & can't be bothered to learn skills, you buy on ebay & often see "Condition is Used" on Records etc when condition is important. They see an Unplayed Library copy made £75 if Discogs doesn't say what grade the ££ copy was so their tatty one is worh the same & there it'll sit for years. The Non Expert thinking they know it all is a menace to the buyer who expects a certain quality.


Luxman Valve Amp: Too Ambitious Upgrade-Redesign.
We have the 1979 Luxman LX 33. The design was terrible throughout beyond the three transformers. Because this is 'our game' to try to get it to be it's best which isn't quite done we notice & previously it took Three Years to get it to the current level. A customer with the 1977 Luxman LX 38 asked for us to redesign the thing from 110v to 240v & redesign to use less awkward valves. This is a huge amount to do & to get it right testing technically is possible, but remember our LX33 took 3 years on & off to get right. It's not really worthwhile going to change so much, the customer would be better off with a "starter amp" with the features & voltages as required & go from there. Yes, but what amp is there, you'd not bother with the Modern crop of Valves amps or even that EAR Yoshino one as they are all flawed from the start. People try to get transformers which usually are far bigger than the custom Luxman ones & end up making their Valve amp but it's not a tidy item. The preamp we used with our 100w Tube Technology Monoblocs was our 2nd Generation one we done in 2008, but now see it's not easy to take apart to do anything, so as we had 2 of the TT preamp chassis, a few years back started on building a better preamp that could be taken apart, but then it just sits in a drawer with no components fitted for the Phono & Preamp as realistically we'd like a LX33 4x valve board to start from & use that design. Good ideas hit stumbling blocks, our TT monoblocs haven't been used in years now since once comparing the Sony TA-3200F power amp & finding the Sony sounded better. Any sort of Custom Design Work takes a lot of time & fine tuning to get right, three years on the LX33, three years on the 1963 Trio WX-400U with both here at one time & getting ideas swapped amid both. We recently rebuilt a 1965 Rogers HG88 III that sounded really great as it's one we'd done in 2011 & just updeated with ideas found since. But to start from scratch on a bad design with awkward valves, not ECC83 & EL34 really isn't what we'd do for a customer as it'd cost a huge amount that really couldn't be estimated & probably be years to perfect.


Looking To Buy 1975-76 Era Amplifiers & Receivers.
55w Sony TA-3650 amplifier from 1976 & 50w Hitachi SR-802 receiver from 1975. Both known brands we've had several earlier models of. The Sony one we had before, if the mean seller passed of a flood damaged one that was junk as they knew & abandoned it. Workman type amp, nothing special or fancy about it, the big one capacitor is 2x 10000µf in one can, the trouble is we're finding amps of this age needing the main caps done & to do right means redesign, if it could be done, the thing might not look so great inside. Ones online around £150 if the auction one makes £83 delivered, we'd have to put a recap-upgrade into it & really only put £495 on it which doesn't really cover the work we'd put into it. The idea is to buy, upgrade & make a profit, not take a loss, so we leave that be. The Hitachi we liked their 1971 range if they needed a lot upgrading, here the SR-802 looks decent but sadly an IC on the power amp early stages for Differential & Pre Driver is no good to us. Again buyable under £100 but again there's not really a profit in it for the work needed. Some of the ones we have for sale continue this "not much profit" for the work done, so in some ways the quality work we do is outpricing the midprice amps. The days we could buy the better amps in at budget-midprice amp prices today is where we got many as this site proves if that is what has people putting too-high prices on "Raw" amps thinking they are worth "Rebuilt" prices. One customer with a boxed Yamaha CR-2020 that we did some work on if not a full rebuild prices it at fully redone price which is not realistic. Another Sony TA-3650 with a missing control knob thinks it's worth £100, who's got the missing part? Actually we do if it's too bashed up to consider that one. We keep looking for Interesting Amps if we've probably had nearly all the 1965-71 ones now.


Beware The Hype On Modern Valve Amps.

Actually beware the Hyped Power Ratings on Any Valve amp, they always are rated as "something unbelievable". One on ebay this month... "AudioValve Assistent 100 mk2 integrated valve amplifier 120 watts a channel" uses GU50 strange Russian Valves from the 1970s. These you can see easily are 50w on Wikipedia & other sites. 50w is all you'll get Push-Pull or 'single ended'. So where does 120w come from. It's nothing special inside, the PCB has 'Prometheus 100" naming. Several sellers on ebay appear brokers who put ridiculous prices on yet some just put one photo & very little info. Here 'audioprestige' put more info, but a price of £6000 for what we see is ridiculous. For 120w similar to our Tube Technology Genesis Monoblock that uses 4x EL34 to get 100w, where are the huge transformers, the 100 Mk 2 doesn't have them. Looks more like a 30w amp to us. These sort of amps seem bought believing the hype & soon sold at a huge loss, this amp with powder coated plain case & £5 remote control looks like a £1800 Made In China amp to us. These amps are always the same unadventurous rip-offs of the 1950s-60s valve amps, they don't sound very good & even with that EAR Yoshino we had recently, the designs are just not very good & have to be tamed.


May 2019 Blog

Don't Just Jump Wildly Into Our Amplifiers, Read Up First, Take Your Time.
The customer who asks about a rebuild on one amp, then thinks to get another, then we suggest ones of ours, they make a low offer & asks all the questions that the site answers for Buying really needs to Slow Down. They've not read anything & are seriously getting it wrong. We don't need unaware customers like that who will forever ask annoying questions & demand what isn't offered, so to say "Slow Down & Read The Site" so they better understand things needs saying. They have 30w Gold Tannoy 12" so they don't need a 100w expensive amp when one of lower power if similar quality will do the job, we see we are wasting our time here, 30w speakers they have. They are Wild & Unpredictable, to sell them an amplifier or do a rebuild is best avoided as they haven't bothered to read about what we do which no one else does, Rebuilds With Upgrades. If they did buy they'd forever ask weary questions that the site already covers & to regret selling to them, so we have to send them away to learn the subject better. Many would just sell the most expensive one to the inexperienced buyer & let them get on with their clueless games, but we want to sell you The Right Amplifier, similarly telling certain amps aren't worth upgrading to help you get what you really need. We try that person again to see if they calmed it down a bit, but suggest a modern 1992 Technics power amp with the big meters, that mass market IC junk shows that they really don't have a clue. We advised they sell the 30-35w Tannoys as they will just trash them with a 170w SEA-7000. You can't help 'stupid' & this person is just wasting our time. Thankfully most who contact us are better wised up to Hifi.


We Do Custom Upgrades, Not Like-For-Like
Hifi bought in a Shop is Always a Compromise between Cost & What is Good Enough. This is why Hifi Lovers forever search for "Perfect Sound" but will Never Find It as it's Not Offered at Any Price. You see Recapped Vintage Amps online, but why do they sell it, beyond those who Rebuild-Restore to resell multiple amps. It's because it's not really that good as nothing is Upgraded, they just do Like-For-Like, ghastly Capacitor Stuffing etc & as they are disappointed, they want to sell it & keep looking for the Perfection that is Not in Shop-Bought gear. Only Custom work by one who dares to try further & ignore the "Grey Old Men" of the past & to question "Why" on seeing poor design will give you the sound you crave. Custom Work takes a lot of time to get right, to work out things that can be bettered on some amps took us 2-3 years on amps we got early on, like Sansui 3000A & Akai AA7000 from 1966-68. These ideas, now tried & tested we put a certain amount into Any Upgrade, if further Custom Work on our Own Amplifiers helps further what we can offer & keep our work Resonably Priced. We know people search in Vain for "That Sound" & never find it, but then they buy one of our Upgraded amps & as they may get one of ours we've Upgraded far more than an Amp bought to Upgrade & Sell, they've actually Found their Perfect Sound. It has taken Years for us to Upgrade to Find that Sound ourselves, using Headphones & Tannoy Speakers, the Best Amps can really be World Class & better anything you can buy at Any Price elsewhere. To see Bad Design-Dumbing Down in Hifi that is on any amplifier & correct it can be very difficult, we do 'Breadboarding' of sorts to get the right sound & then tech tests to see it's right to fine tune. To Upgrade right needs All Stages Upgraded, you can't just do one section thinking it'll solve the lot. This is what we have spent years doing & we get great results. Custom Work is possible to get the Best Sound out of many amplifiers, if those asking for 110v transformers upgraded to 240v ones will find no-one does this, even Transformer companies can't be bothered to work this out. Look online, you'll find some doing what appear Sophisticated Rebuilds redoing paint & casing. They brag about rebuilding boards & changing things, yet every single one we've seen totally misses the Real Upgrading Custom work we do. Try us.

Your Amplifier Is A Compromise, Dumbed Down & Poorly Designed.
The Harsh Truth of Hifi is most is just a compromise between Price & What will Impress you on first listen to buy it or decide to keep it. The more you listen, the more your Hearing Compensates for lackings in the Amplifier as you get used to it until you hear better. Further truth is some of our Favourite Amplifiers & Receivers are actually Nothing Special as Original & only come to life with our Upgrades, so don't all think the 1965 Sansui TR-707A is a brilliant amp as original as it's far from it & even upgraded to how ours is, it sounds wonderful if the background noise even without Germaniums is a bit high. We do tell that some amps are just that which is why we Rate as Original & Upgraded. Heavily Dumbed Down amplifiers we started to noticed with 1970-71 era ones, big name amps like Akai & Hitachi, these amps upgrade nicely with all the limiters sorted, but as original some are very average. The 1965-69 amplifiers are generally with the best designs if now too old to work right or be reliable for Daily Use, but they have been Our Favourites as they bring Great Results. These we've mentioned before, but Poor Design is just cynical, some amps have "rubbish bits" such as the 1971 Sony TA-1140 preamp & the 1970 Akai AA-8500 preamp. TA-1140 has a terrible spoiler in the preamp that we redesigned taking ages to perfect via Tech testing, it now sounds great. The AA-8500 we've had twice before & to know the problems but what to do about it as it's a complex 4-transistor design with a ridiculous high NFB. To sort that took getting the TA-1140 done so the AA-8500 gets tried next & brings success. But Tech Testing as in Sine waves & Oscilloscopes shows Poor Design on one stage we didn't alter, this is their design & it is just weak without giving a quality that it should, it clips assymetrically & this means all other transistor stages will get a poor signal at a level that is below Full Power on the Volume control setting, the signal at higher volume will start to flatten off & sound awful, in the mid 1970s Pioneer way that sounds dismal. Flattening off is the same as Clipping. Add to that Just about Every Amp Post 1967 Has Bass Limiting, the 1966-67 Pioneer even have a nasty "T" Bass filter that causes that unpleasant Retro Bass-Lumpy Bass which soulds awful on Speakers, the blurry one-note mess from Ringing. Reading the 1972 HFN/RR the LIndsey-Hood Amplifier is being released with the circuits & tests. The opinion is from the HFN lot is it's a great amp. To us, it's awful, Input signal goes through big resistors, heavy bass limiting, nasty Zener diodes & from reading HFN before, it has several later alterations done, yet people think it's a good amp? HFN has a heavy "Quad" bias, their ad is always facing the Editorial page yet from the circuits we see Quad are just dumbed down to make the ESL electrostatic sound good. All other people's opinions & we don't take too much notice of those "Grey Old Men" & the type of TV-Grade tech who insists the design is right unaware how Compromised it is. But the Good News is the better amps do Upgrade well, even ones with basic preamp ICs, the Bad News is no-one else has yet advanced into Hifi like this beyond us.


Your Amplifier Is A Domestic Hifi, Not A Studio-PA Amplifier.

If you've heard the Studio-PA type amp you'll have heard it's capable of being Very Loud without flattening off or sounding harsh when played Louder. A Clean amp with Huge Dynamics is a joy to hear but be sure you'll play it at home too loud & be the bother of Neighbours. Very Fast amps with Fast Slew Rate & Rise Time. We upgrade amps to max them out, because we can. Example the 1970 Akai AA-8500 is a bit too tamed for our taste if it is a great amp, it's too hard on the NFB giving a more polite sound that we aren't keen on. So we got ours & redesigned the preamp board totally to hear that Huge Sound again, if only on headphones, on our Tannoys it needs more work perhaps, if to sell it on rather than alter it too much. It has Doubled Output Transistors too & really is the only amp-receiver that does this beyond the 1965-67 Sony TA-1120(A), the Doubled-Tripled Outputs make the 150w+ amps of the later 1970s, if on the 1970 Akai it was as the output transistors they had were only 50w & they wanted a higher power amp. The Huge Dynamics are actually a bit Overwhelming as you're not used to such a big sound, it's a lot louder for the speed of the amp. Imagine if in 1970 Akai sold an amp like this, buyers would complain it was overpowering & not understand the big sound, much as the 1973 Yamaha CR-1000 receiver has a similar "too loud for Domestic" sound. This 'Big Sound' does need a lot upgraded to cope with it & an amplifier has to be of a good quality to take this redesign. The 1973 Yamaha CA-1000 we've tried to do similar with, but it's Filter Stage is truly awful, if the CR-1000 one is better if it brings up hiss & the silly FET compromise to lessen it. All Amplifiers are a Designer's Ideas at the time, sometimes Genius, sometimes almost Hateful of the job... look at how Sony changed their designs radically from each amp 1965-1974. These Somy amps as original all sound fairly similar, the Sony Sound if the designs are often completely different from year to year.


Oops! We Plugged A 110v Item Into 240v. Is It Dead?
We had a customer ask this about 2 Monobloc Amplifiers. There is no way to tell what happened. If it just blew fuses to try new fuses & see what happens. The customer said they did this & no life. Fuses in the Plug or amplifier will generally protect any Mains error as will a Circuit Breaker which we use on trying any amp the first time as it cuts out very fast. If it smoked or caught fire odds are the item is trashed, but Hifi usually has Fuses that will blow to save it. Fuses must be used correctly, a 3A fuse covers to 720W, a 5A fuse 1200W & a 13A fuse 3120W on UK's 240v. If you don't change a 13A fuse to the right 3A or 5A fuse you're not protected & your amp will fry, we had a 1969 Sony STR-6050 an amp that insanely has no fuses at all & it had a burnt out transformer as clearly the plug was a 13A fuse as was generally sold at the time. UK Woolworths in the 1970s sold 13A plugs but few bothered to buy 3A or 5A fuses or even the less common 3A plug, as they had no idea they were needed. We put the right fuses in plugs & after doing many amps we have over 100 old 13A fuses taken from plugs. 240v is twice 110v & depending on the item double the voltage & double the current will trash the item. 240v items plugged into 110v may survive a bit longer if could draw Double the current & get trashed. Today you see cheap electronics with Switching Power Supplies that say 100v-250v & you can plug them into any voltage. We're not keen on that as it can't be optimised for either voltage & using 110v or 240v is likely to burn it out faster, if today's Two Year lifespan of Electrical Goods & Phones means maybe it just lasts long enough in that Built In Obsolescense cynical way. A Burnt Transformer is very smelly as the varnished wires overheat & the smell as with the Sony amp will linger forever. To see if the Transformer is working or not takes easy tests by a Tech, not ones we'll publish, if it has voltage still odds are it's fine, but no voltage means the transformer is dead & we had this with a valve amp once to need to get a replacement transformer. You may have burnt out the power supply if the transformer has survived, but generally you have the gamble of a dead transformer with power supply damaged, or if you're lucky & your circuit breaker & correct fuse turned the power off, your item is fine, if you'll need time to trust it again.


Our Old Favourite Receivers From 1966-67 Revisited. Part 1
Fate nearly has Five of our favourite early Receivers here at once as of typing, the Sansui 3000 is the 1966 version of the 1968 3000A, the 1966 Akai AA-7000 is our first one we bought back from the customer, the 1967 Pioneer SX-1000TDF is almost the same as the SX-1500TF as we had one here only recently, plus two from customers, the 1967-68 JVC 5040U and National Panasonic SA-65. The Sansui 3000A & Pioneer are still findable in the USA if the earlier 3000 is rare like the other three receiver amps. All four once rebuilt-upgraded sound great if are different sounding as are all amps. A Severe Nerd-Fest on these Five really as they are ones we rediscovered & now others are now enjoying them, if be aware these all need an expensive rebuild as they are beyond useable really as so old, the money is well spent. Originally the Sansui 3000A we had ours three years, the Nat Pan we had two years, the Pioneer SX-1500TF we had about 18 months before old repairs caught it out, if today we'd not part it out so easily. Akai we had ours about two years if did sell it to now have it back after having one here to rebuilt & fancied a retry as we got the Akai AA-5000 amplifier. The JVC 5040U we didn't keep so long as the wood case was rough & the amp isn't the prettiest if the 75w makes up for it. All Fascinating Amps, all Great Sounding amps, but none 'perfect', but no amp ever is. In terms of Upgrading to our standards now, which would we keep longer to do more with? To hear them played as near together as a Comparing Session needs to be done, so that'll be Part Two sometime. We've got the SA-65 opinion based on the AA-7000, so once all tried to get more to tell.


Get A Nice Grade Amp That's Not Been Fiddled With.
The importance of that shown by getting one of our Favourite 1966-68 receivers again to work on for a customer. All rebuilt & upgraded it sounds great, but to have things meddled with sort of spoils the joy. Here it had been recapped badly with long wires left all over the place, untidy job, to just strip it all out & do it again properly as not worth risking trying it. Then it has a missing control knob as the balance must have got smashed & the potentiometer inside was replaced untidily. In transit the selector got broken through the front of the knob as it got a hit. They'd revarnished it badly with coloured varnish if again an amateur job. Then this person managed to lose the perspex type coloured sheet to give the tuner light the right colour and the red Stereo bulb bit. The wood case screws they used big wood screws as they managed to lose the original ones. Often amps that have been opened lack screws, do they not bag them to keep safe? The Akai AA-8500 on our Solds Gallery they replaced rear transistors & managed to lose the full width metal grille that covered them, so we had to put mesh to tidy it. The Joy of getting a cared for amp with all the right pieces intact, often ones untouched since new if some have had repairs & done correctly. Some amps you still get the Blanking Plugs & the old solder-type Phono plugs still there untouched from new, our current AA-8500 had these & to have a high grade one after having a less nice one really is nice to see. Some amps still have all the booklets & guarantees, plus shop receipts even. There's not really a Collector Market for these, if to have the manuals is nice to have to show some History on an amp as you rarely know anything. We'd rather get a nice grade outer with aged or damage inside as we can rebuild the insides, only when visuals are missing or tatty does it leave not much to do, we don't do cabinet repainting or veneering if can tidy to a degree. Lettering that wears off a fascia is a problem too as it was screen printed & ones like the Akai AA-5800 that lose the print haven't been well matched or cleared over, some that have the lacquer can wear off with a smoker's nicotine turning it soft. To put a good job into a tatty amp will get you a nice sounding amp still, but the looks will really only be what they are unless spare parts can be found or someone makes or refinishes the outer. Another Yamaha receiver we have here, the buyer got a bad deal as wasn't told of the broken antenna which had a loose wire that couldn't be refitted as part glued in, but amazingly they kept looking & found one on ebay from a parts seller so it's on the way. To find rare parts like that is pure chance, you might look years to find another as who'd part a Yamaha receiver out?


The Question of 4 Ohm & 8 Ohm Speakers, Power Ratings & Sensitivity.

In Theory an Amp rated 50w into 8ohm should output 100w into 4ohm, it's half the resistance so power should be double, but if you look at Amplifier Specifications, it's rarely this. "Why" is down to Amplifier design & the limitations of the Amp Spec, so you'll see some amps 50w 8ohm rated 60w 4ohm or even 40w 4ohm depending on the Amplifier. You'll read of extremely high power post 1990 amps Doubling, so 400w 8ohm, 800w 4ohm & 1600w 2ohm, but these are not really 'Hi-Fi' amps despite the manufacturers claims, they are just High Powered & Heavily Damped meaning they don't sound very Musical, if some think you need this power for Domestic use. An example on Speakers are Tannoy Gold 15"s rated 8ohm if 5 ohm nominal means the Impedance Curve dips to 5ohm. We've yet to find even the early "8ohm only" amps like the 1966 Akai AA-7000 having trouble, if we do know this amp doesn't like 4ohm speakers as it goes outside the design limits, we know exactly as that AA-7000 was our redesign & to use different voltages for the 4 ohm load it upsets the design balance we put in the amp. Many Amplifiers have Two Sets of Speaker outputs & some even have three, but these are wired to only use 2 sets, not 3. The Two speaker Amps often wire the Speakers in Parallel to not put a heavy load into the Amp, ie to push "Spkr 1&2" puts 8ohm in parallel with the second 8 ohm to give a 16 ohm load which won't be so loud, but it saves the amp for putting 4ohm + 4ohm together to get 8 ohm load. Other Amps add a 2ohm or 4ohm resistor when using two speaker sets. The Basic Idea is 8ohm speakers will be fine on any amp, they may match to give a great Tonal Balance or they may sound Unbalanced as we've mentioned on the Speakers page with many examples. 4ohm speakers need care for what amp you use & never try to run 2x pairs of 4ohm speakers from an amp unless the Manual says the amp can cope. If the amp sees a 2ohm load with 2 4ohm pairs it will likely overheat. 4ohm speakers have been around since the 1960s, as blogged before the Impedance Curve needs to be seen, as if the 4ohm impedance drops below 2ohm the amplifier won't be able to cope. Some Speakers as blogged before are "Notoriously Hard To Drive" this means they are badly designed & will potentially cause problems. We hear amps we sold KLH 52 & NAD 3030 which are decent midprice amps are struggling to drive 4ohm KEF floorstanders. To know the Model Number to see the KEF impedance curve could help, if both those amps are only medium power 30w & the dB Sensitivity of the KEF may not be the 95dB of our Tannoys & to push the smaller amps into distortion to get a louder volume suggests these amps & KEFs are not physically matched. To get a higher power amp will help, if ultimately the KEF specs need to be known. Speakers with 4 smaller drivers will not be the high 95dB sensitivity. Low Sensitivity Speakers. As an early example, we had a 1967 Sony TA-1120A when we had the Tannoy 605s & found the volume needed turning up high to get enough volume & this was almost at Full Power. The 605s are 87dB which is typical for the size, the bigger 609 are 89dB. These are rated 10w-90w & 10w-120w. The "10w" is the minimum needed to drive these, so no good for 5w Music Centres. With 95dB Sensitivity Speakers compared to the 605s you get 8dB extra gain. 8db is not far off Twice As Aloud (10dB), so see an amp gives 20dB gain add that to 87dB or 95dB to see the maximum volume. 87dB speakers are Strictly Domestic, 95dB ones are used in Studios.


The KEF C95 Floorstanding Speakers vs KLH52 & NAD 3030 30w Amps.
To see what the Customer is hearing in a situation many must be facing, to say "but have recently 'upgraded' to a pair of KEF floorstanders which are only 4 ohms, with both of my amplifiers struggling to drive them." We can play any amp of 15w or more with ease into our 95dB Tannoy 15" Golds we got in 2002, but they are a Top End Speaker that is now getting too expensive & even the later HPD ones are rising fast. KLH52 & NAD 3030 are midprice amps from 1970-78, the KLH the better of the two, the NAD showed it's 1978 cost-cutting. KLH52 puts out 20v Clean Sine as we read, if didn't rate the NAD if 30w is typically 20v output. We don't rate into a 8ohm resistor as no speaker is an 8ohm flat impedance. KEF C95 are 1988-91 says HFE, 3-way driver rated 90dB. KEF have been around since the late 1960s in the Hi-Fi Mags & are a Popular Brand with Better quality goods from an overview of the 1970-80 era. These can be Biwired or Bi-Amped, neither of which make any difference, the cohesion of one cable driving the speakers as designed is always the best idea, to avoid colouration by ringing, by leaving a big range of the sound unused by the speaker in Bi-Amping seems a strange idea, if good for Cable Sellers as you Buy Double. The last smaller sized driver speakers we had were the B&W CDM 1NT, sounded good loud, but too thin quieter & needed 1.5 "notches" up on the Sony STR-6120 when we had both around 2003, suggesting the Sensitivity is low, raking through the manual online shows they are 88dB & need 50w minimum. KEF therefore should play 30w amps with ease to a decent level & including Tone Control, but the 4ohm load is the added difficulty. NAD 3030 specs rate 30w into 8ohm & 50w into 4ohm & even rate 60w into 2ohm which is unusual to quote, but show the NAD should cope well. KLH 52 has the specs as 30w into 8ohm & 38w into 4ohm, this should cope well into the 90dB KEF. The KEF C95 manual suggests 10w-150w 8ohm & 20w-250w on 4ohm input in the specs. This seems typical, 10w minimum to use the speaker is an easy load for these 2 amps to drive. No Impedance Curves findable if other KEF look 'easy loads' to drive. The only question is how large is the room & how loud the owner wants to play music. Speaker & Amps should give a good volume but not "Party" level. The Quality of the Amps is another thing, both KLH & NAD aren't Top End models & to expect a confident sound up loud where the volume is likely at 12 o'clock or higher means you're just playing the amp too loud so it goes into distortion, flattens off & sounds rather unpleasant. We've done tests with 20w Sansui 400 from 1967 together with 100w Sony TA-2000F/TA-3200F & once you crank it up louder, the 20w amp just can't cope past a certain volume level, when the 100w amp gives that extra, even on 50w speakers used carefully. For most Domestic Uses you don't really need more than 40w-50w in a typical UK sized room, if you have a Huge USA Basement then you'll need 95dB speakers plus the 50w amp to do justice.


Four 1965-73 Amplifier Phono Stages Tested.
To try these amps for their Phono stages using the amp & play on Headphones. All amps have been recapped & upgraded. Similar tests as on the Turntables-Phono page, to use our Technics SL-120 & SME and Goldring G-850 that suits Mono vinyl well as it's a 1970 cartridge using a Conical stylus. We need Treble Gain on all amps, if leaving Bass flat plus Mono switch. The Four Amps include 2 we have for Sale currently, 1970 Akai AA-8500 and 1973 Trio KR-6340 as a customer asked for a compare & to add the 1965 Sansui TR-707A and 1973 Sony TA-1140 to give a better comparision. To pick two 1960s singles to test with, Loud Cut ones need a good Phono stage as per the earlier test. Tracks we choose from stock: 00165 Cops & Robbers 'Just Keep Right On' a midtempo track that has a 'recorded live' sound & 00272 Peter Fenton 'Small Town' that is recorded loud with high treble to need good resolution. The Reference is our own Valve Phono design in the Luxman LX33 that resolves these tracks beyond any Domestic Hifi. So to try the Sony TA-1140 first, the C&R one sounds nearly as detailed as the Valves, similar on the PF, both sound very decent for a Transistor amp. Depth & detail not as deep as Valves but impressive. Further compares suggest this amp isn't true to RIAA as it's too Trebly, perhaps it's been altered if we've not taken much notice of the Phono beyond recapping. Sansui TR-707A next, this is similar to the Sony if detail is better focussed on both tracks, it's also a bit upfront lacking some depth & sweetness to the sound as confirmed playing a few other 45s. We remember the Fisher 1960s Phono stages were similar, a bit hard if detailed, making Headphone listening less pleasing than the Sony here. Again this doesn't sound like a True RIAA Phono stage, it's more trebly & seems peaky on midrange. Now the Trio KR-6340, a 4ch amp if Phono is 2ch if has 4ch decoders. After the upfront 707A sound this is less defined, upper bass a little thick compared to the Sony sound. Not a bad sound but a little blurred on resolution that loses the PF record's bright trebly sound. Akai AA-8500 next, similar sound to the Trio. Phono is better focussed than the Trio on both records. This is more true to RIAA as is the Trio. Conclusion. The Sony is brighter on Phono & from playing many amp Phono Stages this isn't strictly the RIAA sound curve as treble seems about 5dB brighter than typical amps which the Trio & Akai are more like. To us RIAA is less trebly than the 'Sound' we like, our Valve Phono is designed to a sound we like that suits 1960s Vinyl. The 1960s Phono stage on the Sansui is found to be a bit hard. Phono Stages do vary a lot in Tonal Balance, they all Claim to be ±0.5dB accurate to RIAA, but in NFB Phono Stages it varies a lot on the design. Even heard from a Hifi shop dealer saying post 1972 records have Different RIAA, which is true in the idea there is the first RIAA from about 1954 & an 'improved' one that gives a slightly different response more suited to later records. RIAA EQ has always been a rather varying sound on Amplifiers. Oddly an earlier section on the Sony TA-1140 said we thought it sounded dull which the TA-2000F stage does, perhaps the TA-1140 has been altered to sound brighter? In General the Tonal Balance can be sorted with Tone Controls, the Qualifier in a Better Phono is how focussed the sound is on playing detailed music. Phono Stages are very varying & from trying on a Sony STR-6120, to try to get the Valve Sound as our MP3 samples on the Sales Pages show, to design Transistor that good is very hard & we've not tried since which was about 2003. Design Values. The Akai uses a typical EQ circuit that is familiar from later amps, the 0.0068 & 0.0022 are commonly seen. The Trio uses Phono for Tuner, Phono & 4ch Matrix with non standard values. Sony uses very similar value to the Akai so has to be altered to be that Trebly. The Sansui values are very different. The Akai balance is more true to RIAA & would suit users of later amps better, for a more familiar sound. These values can be tweaked to the sound you like by experimenting.

July 2019 Blog

Don't Trash Your Amp By Mistake, Take Care With Speaker Cables

The Number One cause of a Damaged Amp beyond aged parts, is the Old 'Shorted The Speaker Outputs' one. From a stray strand on using the older screw connectors, to Awful Ideas using those Gold Plated ones fitted 3mm apart to replace old ones, oops dropped a screw & it shorted. Then the Fashion again to use Solid Metal 4mm Gold Plated Plugs. We don't use these as even when using speaker & cables, we saw these needed electrical tape to isolate as just too close together. a large metal surface rerady to short out. The spring Connectors first used in 1970-73 by Sansui, Marantz, Pioneer etc are the most foolproof safe way to use Bare Speaker wires, if today's cables are often too big. Even the 1976 Marantz 2385 uses larger hole spring connectors, we need to use a wire adaptor to use 4mm plugs, save hacking the 2385 case to fit 4mm ones. We see one of our Sony STR-6120 got damaged by the outputs shorted. They shorted at the speaker end as the 4mm metal cased plugs got accidentally pulled out & the metal ends touched. The owner was using Ferrites as we say, but these are to be used One Per Wire, here two in one Ferrite pushed the metal ends together. So What Do We Use. As on the Sales page we show cables & plugs we use. Some amps have widely spaced metal connectors like the STR-6120 has, if the bare wire & 3mm plug holes aren't so useful. So take a look at the Trio-Kenwood KR-6340 that we've upgraded far more & are using on Speakers ourselves as we type. Note the 4ch amp has 16 speaker connectors. To refit all those on some amps is a bit of a job, but Trio 1971-73 at least used screws that are the same size as the VOSO sockets we use. Remove the screw past it's slight binding crimp & screw in the sockets tightly. It looks like This with VOSO sockets. The original screws were like the 4 Antenna ones, it was tricky to use Gold blocks & the idea to use skinny wire with 'T' Antenna type connectors must have ended a lot of amps. Note we use Red & Black Plastic Cased 4mm Plugs, they are just good basic connectors. VOSO appear Chrome Plated, the 4mm Plugs are some generic Gold Plated type with "ProfiGold" wording, Gold Plating not worn off & used many times, plus the cables are QED Balanced Design Concept ones bought in the early 2000s. The hideous Chunky Gold Plated Ones usually wear the Gold off fast. We needed some fo the Sony TA-3200F power amp so found medium sized Gold Plated Metal ones in a plastic case, blogged on these before. The Cable end on the Tannoys is big Gold Plated Sockets if the plastic cased plugs. Widely spaced, but again drop a screwdriver down the back & you could short the speakers. So we'll go Isolate those next with Electical Tape or Heatshrink. Easy enough to tape if heatshrink needs to be a large one. Looking up & seeing the TT valve monobloc amps these have big Gold Plated Metal Plug sockets. Sat out of the way not to be touched we used these for 15 years without problem. Heatshrink on those 4mm Gold Screw Blocks is another good idea. Throw Out or Isolate those big Gold Connectors before Your Amp gets damaged if there is any chance movement or regular amp swapping could get outputs shorted.


What Happens When You Short An Amplifier Speaker Outputs?

Beyond the obvious damage, what happens is the Output Load instead of being 8 ohm or 4 ohm, suddenly drops to 0 ohm. Unless the Amplifier has a Proper Relay that actually monitors the Output Bias & DC offset so it will cut out, the amp will just draw far too much current & trash itself, usually causing burnt resistors & a selection of bad transistors. The amp can be fixed & any board burns can be tidied making the amp safe, reliable & trustworthy again. Looking at old amp repairs, often the TV repair guy botched the job with whatever they had around, but if it worked, what do they care? The parts that fry are Output Transistors if some of high power may still be OK. The Driver Transistors are the usual ones to fail plus you may damage other parts, it's a Repair Tech job. It's sad to see a burnt out amp board, but most is debris so it cleans up, but needs quite a bit replacing & skills to know what may be hiding damaged. Relays To Protect? The 1965 Sony TA-1120 had a relay & a slow start feature. The manual claimed you could short the outputs brutally & the amp would turn off the relay & soon recover. The 1967 HFN review actually tried this & proved it worked. We didn't fancy trying that ourselves if enough prof it worked. Great Idea & so early, yet other amps into the early 1970s didn't use relays. What they used appears pretty hopeless to us, but one often used. To cut power from the Preamp to show the Amp had a problem, but the Power amp & speakers were not disconnected so damage to amp & speakers could occur. We know the Sony TA-1130 does this & one person appears to have used 2 sets of 4 Ohm speakers so severely overheated the amp, but only knew of trouble as music went quiet, the power amp kept running so much it melted the Potting Compound in the Maibs Transformer casing. Amp worked fine still after some tidying, but if left unattended it wasn't blowing a fuse or damaging any transistors so could be a Fire Hazard. The 1969 Sony STR-6050 foolishly has No Fuses so relies on the 13A fuse in the plug only, it should have a 3A one which would have saved the Transformer from burning out. Protection Examples. The 1971-73 Trio Kenwood range with the KA-6004 & KR-6340 we have 'samples' the Outputs from the Power Amps & will shut off if the Bias Current is too high, much like the TA-1120 did. Other amps sample the output similarly to turn off the Preamp to 'warn', but seeing the Preamp voltage goes through the Warning Bulb until it gets grounded to show the fault, it's not a good design to the point it's better without it. The 1976 Marantz 2385 has two relays, one on turn-on when mains is used correctly by the amp & one after seconds to turn on the speakers once the power amp is seen to be correct. False Hope. The Capacitor Coupled power amplifiers mostly used pre 1972 do offer a permanent protection to the Speakers, based on the output capaitors being good, there will be no stray DC possible on the output capacitors, ignoring the fact some charge can remain on first plug-in to create a small noise. But the Signal being Shorted will still draw excess current so the Amplifier Stages can damage. The Safest Amps To Use are Capacitor Coupled, Valve-Tube ones with Output Transformers & the Better Relay Protection circuits. Old Aged amps with relays may protect from damage, but remember the amp is aged so the relay detection circuit can be aged, mid 1970s Pioneer fail on this quite often. Not all amps with relays do what you expect, the Akai AA-8500 has a relay, if this is only for the Muting Stage via an optional remote control box. Some early ones 1971-73 only turn off power but don't disconnect speakers. The Start Of The Relay on Speakers Protection Era. The 1965 Sony is clearly the first ever to use a relay, if the 1967 TA-1120A omits it. The first of later amps to use a proper speaker disconnecting relay are 1971-73 Trio-Kenwood with KA-6004 & the 4ch KR-6340, the 1971 JVC VR-5521L does too but some Relays only turn off partly. Relays only started to become Standard with 1972 Pioneer SX-828 & 1973 Yamaha CR-1000, CR-800 & CA-1000 etc, if only higher models get them. Modern Marantz PM-6002 from 2007 has no speaker relays, if one bonus of today is they use those sealed blue relays for input selection. One way to be sure a post 1973 amp is of High Quality is to see it has Speaker Relays, if plenty mid & lower models don't have them.


The First Hi-Fi Magazine "Truth" in 1974 About Cost Cutting In Amplifiers. Pt 2
Audio T appearing to 'mouth off' without giving details why stirred the UK Pioneer distributors 'Shriro' to write a letter as in the March 1975 issue. Having read the 1956-80 HFN/RR mags to go through them again having understood the scene like one who lived that era & to find Gems like this is why we're re-reading. Audio T understand the 1969 amplifiers sound better than ones from 1973-74. We have put 1973 as the last "Good Year" of Hifi if 1973 Hifi has moved along hugely from 1965-67 First Generation Silicon Transistor amps. Not much after 1974 appeals to us, which is why we tried so many Yamaha as they were better than the typical of the era. But what Audio T are doing is a "Pioneer" thing too, obvious pun noted, but they are describing Hi-Fi Subjectively that rarely featured in earlier years, when it did it was so general in wording beyond "we liked it". This era had Martin Colloms start in HFN/RR with his first review giving a taste of the more Subjective plus extras like Rise Time & Slew Rate as blogged before. These factors soon disappeared as did Poor Square Waves showing extreme downward tilt at 40Hz as the amp was severely limited on Bass & also 1kHz square waves with curved rising edges showing a slow low-spec amp, often show as a lot worse by 10kHz. This 'poor square wave performance' was usually glossed over & the reviewer still rated the amp highly. We see bad Square Waves as a substandard Amp, having tested our Upgraded Amps, getting very fast slew rate with enough spec to give a high quality sound, a thing no shop-Bought amp ever has. Pioneer's Shriro letter is half the page & attempts to Waffle to cover up what Audio T says. It just says nothing really, just points out facts but never defends the SA-9100. "They Sell Well" is as near as they come to explain why, popularity isn't a key to being a Good Amplifier. Amstrad sold well but they were garbage that often went back broken on Monday say those selling them at the time. Pioneer know full well they cost cut to underprice other brands yet never mention price. 1974 was the first Cost Cutting Year as Comet & other Discounters wanted to sell apparently good stuff cheap. The letter says Audio T are "Blatantly unscientific and opinionated" which is amusing really as Audio T agreed with scientific tests but their Subjective opinion was "It Sounded Foul". Today such opinion would stand but to be taken seriously Audio T would need to explain in more detail why it was Foul & what it was lacking. Our Opinions on the SA-9500 on having three of them was similar to them Sounding Foul. But this is The First Raw Subjective opinion & is worth re-telling. Most Obvious in this Decline is a Trio-Kenwood double page advert. It shows their rather bland looking new range in the Mar 1975 issue. KA-1200 13w £57, KA-1600 23w £92. But they still list the 1971 range so have KA-4002a 16w £85, KA-4004 19w £116, KA-6004 43w £154 & KA-8004 65w £210. Look how much cheaper the new range is. Looking at the KA-1200 on the Service Manual, the insides look pathetic, cost cut a lot, none of the quality of the 1971-73 ranges. All very basic, still all transistors, but the Old Trio design quality is long gone. More on Audio T's interesting ways to follow.


Listening Tests & Comparing: 1976 Marantz 2385: How Good Are You & Preamp Swapping.
We've had this nearly a year now, it's had a huge job of servicing, recapping & upgrading. the dull muddy slow sounding amp improves each time. without any upgrades beyond Recapping it's still quite tame sounding, tame at 185w it is. It's not a Studio Pro Sound. The 1973 Trio-Kenwood KR-6340 sat forgotten for 6 months since Dec 2018 if comparing to a 1967 JVC 5040U to hear it sounded quite similar on the midrange-treble if the bass wasn't too good. So the KR-6340 gets the Max Upgrades & now it sounds awesome, perhaps the Best Amp we've heard for speed & dynamics, if it took a lot to get it that good plus as the Tone Stage is the Superior Passive type, not the Baxandall NFB type, the sound is fresher as no NFB to cut the Dynamics. The Best Tone Stage is the 1965 Sansui TR-707A & with some mindbending thinking the design can be put in the KR-6340 as we did previously with the 1967 Sansui 400, the buyer of that said they'd never heard an amp so good, because it's Our Design Upgrades, not a Tamed Shop Bought Design. Amplifiers can play Loud & Exciting, such as the 1973 Yamaha CR-1000 & CA-1000 but these amps have quite a bit of NFB so the Sound is very decent but it lacks the Air of a No-NFB design. The CR-1000 can sound better than the CA-1000 if the CR run does vary in how it plays in the Tannoy Golds, if impossible to see why, nothing is different. We've tried to redesign the CR-1000 preamp stages which is very difficult if to hear the CR-1000 without it's heavy NFB was actually a great sound, if keeping it stable is another thing, we'll keep on with it. To the 1970-72 Sony TA-2000F-TA-3200 Mk II. The later version of the power amp without the extra protection board is the better of the two versions. The Power Amp is World Class, the preamp with FETs lacks the crisp focus of Silicon Transistors, FETs are No Good in audio, if just a few amps used them. The 1973 Sony TA-1140 is a 40w amp, the preamp has an awful spoiler in it, if redesigned as we did, it sounds extremely good. the TA-1140 power amp stage can sound great but it it limited by being 40w. So to use the Pre Out of the TA-1140 into the TA-3200F power amp, it sounds awesome. To use Blanking plugs on the TA-1140 Power Amp in save leaving it 'open' especially as upgraded. So to think if the Marantz 2385 played with a different preamp would sound any different, to not rip the amp to bits the TA-1140 preamp used on the 2385 power amp, cables & blanking plugs, remember the coupling switch. 2385 + TA-1140 was an interesting sound. The extra bass solidness for the Tripled Outputs showed nicely, the midrange seemed a little more upfront, if comparing the whole 2385 it's the 2385 power amp sound. The TA-1140 preamp with it's fast open sound is not far off the KR-6340 upgraded sound & the bigger dynamics of the TA-1140 preamp compared to the Marantz 2385 preamp were noticeable. The 2385 preamp is very clean but it sounds a little flat on dynamics as ICs are still limited in spec. The 2385 power amp isn't as lively on upper ranges as the TA-3200F is, there can be impedance differences beyond design changes. Ideally to have the Treble Speed & dynamics of the KR-6340 or TA-1140 on the Power Amp of the Marantz 2385 once upgraded more would likely be a real winner, if to lose the 2385 ICs to build a transistor preamp is likely not going to happen as the ± IC voltages are only 13v so the Power Supply would need redesign & that's going too far. The 2385 sounds awesome as it is upgraded already, but just looking for that extra heard in the KR-6340 may not work out so well. Interesting to swap around preamp & power amp stages.


New Is Better Than Old? Really?
Watching "Counting Cars" S8 E13 Danny says he loves the shop truck, a new pick up that he customised only fairly recently. Says driving the Old Hot Rods is fun for a minute & then reality hits, you lose interest & it's hard on them. Oh My... We see what he means, the Old Cars still with lots of 'Old' in them are not that great to drive, they break down & get problems. The "Chasing Classic Cars guy Wayne selling cars over $1m that are just used as decoration in a Garage & rarely driven. Old Cars are old cars, they are for enthusiasts not everyday use. Ones unrestored are often with tons of issues inside, out & under. You'd think the ones they put new engines in & do $80k jobs on are as good as New really. New actually is Better Than Old, in certain things. But Old done afresh can be better than New, if still retaining 'The Old' that gets the interest. In Hifi New is undeniably disappointing, most now is Disposable, Don't Buy New. It's got the Remote Controls & Ease of Use that you may wish for. The day before blogging this, we used the 1965 Sansui TR-707A, the 707 Jet Age amp, hence the number. It's been rebuilt a lot & still more to do plus the Tuner we'll recap. It's 54 years old, it sounds awesome on the speakers & for the design it still sounds a bit Retro, no other amp has this full rich sound plus the Treble detail. Deep Bass to really floor you. The amp is old, the main board is the old PCB with all new parts on. It's still looking original. It's Old done New. Old has Character, Old has a unique sound that you can remember to an amp. Cars today are very bland looking, no personality, nothing endearing, even the fancy new Ferrari on the same show. Will be a Better Ride if a Boring Tamed Drive. To say Old Isn't So Good when it's your Business to Restore & Improve Old is not a good thing to say. Watching further explains, he knew Burt Reynolds well plus has several of BR film cars & once thinking is saddened to not quite be true to yourself. The 100 Point Restorations in Pebble Beach Concourse type cars we see as Soulless & often don't really see the point in them being more Perfect than new & too scary to drive. Amps in Good Condition but not Perfect Cases is fine by us. To not buy ones too rough or bits missing unless Rare, still leaves you with a great Rebuilt Amp with the Visual issues that grate a bit. The buyer of our 1967 Sansui 400 got a parts amp in a wood case & got the missing control knob cap. Finished it off very nicely. Old can be refreshed to better New in Hifi, but you don't drive down the road in your Amp so more old can stay. But those using Amps with 30-40 year old caps or older are missing out on the Performance of New Caps plus Upgrades to Better The Sound, if many won't upgrade as it takes Fault Finding to tune the amp to be stable sometimes.


Soundcards & Computer Audio: Free Hi-Fi Source.
We've not used a CD player in many years. No need for one really. Upload all our 20,000 tracks to the Computer in .wav format which is uncompressed like a CD is. The only thing you may miss is the ability to select a CD type menu, if Computer Jukeboxes have been around for years & you likely already have one installed or can download one. Setting Up a Souncard, like the Soundblaster range needs a little care. A Soundcard is a better spec one to the one on the Motherboard, the 3.5mm coloured sockets is sound. The £100 type of Soundcard gives great results if not Laboratory perfect on Square Waves for Test Tones, you need a dedicated Generator for that, if Sine Waves are fine. The Soundcard improves the Signal to Noise Ratio compared to the Motherboard & adds extra features. The Soundblaster one has a Control Panel & these Cards are always 5.1 outputs, if annoyingly the default on installing is 5.1 with Bass Boost & other junk, so you need to clear all that else you'll just hear a dull Bassy noise instead of Music. Cards from other makers will vary. Just turn off Bass Boost, Crystallisation, Dolby & set to 2 Channels. Crystal one is a fake effect to add life to dull digital tracks. Then your Computer on the Control Panel, Windows 10 has this on the older Control panel, not the W10 one, yes 2 control panels on W10. Go To Control Panel > All Control Panel Items > Sound. The box shows Playback, Recording etc. On Playback Tab click the one with the Green Tick Circle that is your default as 'Speakers - Default Device', or change it to be that. Another box shows General, Levels, Advanced. Click 'Advanced' & untick "Allow Applications to take exclusive control of this device" and untick "Enable Audio Enhancements" which stops any nonsense, you just want a Flat Soundcard Output into 2 channels. Recording on Soundblaster Control Panel to select Mic or Line In as Mic adds gain boost. Then adjust levels to suit. On Record you can get bizarre huge echoed noise from loops, to Disable "Listen To This Device" on the Recording > Line In Properties Tab. Sometimes the computer records at the correct Volume & other times it does it 10dB quieter, if why it does that makes no sense, maybe it auto adjusts on booting the computer. Put a CD in the Computer CD drawer & play it is the most basic thing you can do.


The Woes Of An Amplifier That Just Won't Fix.
Sometimes an Amp turns up that has never worked & arrived with damage. Some amps past 1980 are considered Disposable for the cheaped out designs, the DC type amps with no coupling capacitors usually trash a lot of transistors & fuse resistors. Fault Finding usually just turns up so much wrong with DC amps like a 1993 Sony we had, it just gets to be too expensive in time & parts to keep on trying. Amps with Computer type soldered boards & Surface Mount parts also get into this territory. Ones with lots of ICs for Sound & User Control are best avoided if faulty. Amps with poor quality parts like tiny sized Balance Controls in the 1984 Sansui AUG30X or tiny Volume with Motor as the 2007 Marantz PM6005 are parts that are unfindable. They are Built In Obsolescence to make the item disposable. Cynical & Insulting for the Money you pay. But we consider amps pre 1980 without tricky ICs to be "Forever Repairable". This goes only so far, amps in poor condition from damage are still parted out as USA ebay sellers reveal. We've not parted out any amp in a few years now, but we have a problem Amp that's been here nearly 2 years. It's a great amp, we bought another of the same model, rebuilt it all, really liked the sound on speakers if a customer wanted it so we sold the good one. The 'bad' one sits on desk now. It's the 1967 Pioneer SX-1000TDF. Lovely sound as upgraded, smooth & detailed. But the SX-1500TDF on the Solds Gallery actually didn't get sold, it had too many old repairs & left the rather fragile power amp a bit lacking in reliability so we couldn't sell it like that so had to quit, we'd probably try more these days if raw ones are often $100 on ebay USA, the shipping will more than double that. The SX-1000TDF here is almost new inside on the inside casing, unlike that SX-1500. So it's had everything rebuilt, even new resistors on the Power Amp as that was considered a problem on finding a faulty Phono board on the one we sold so swapped them. Old Resistors can go open circuit & the Phono board since re-resistored found the bad resistor which kept one channel silent. Resistors done a while ago now, not plugged it in but tests showed it still wasn't right. Just put some old output transistors that we'd kept, to save trashing yet another new set & plugged it in with Headphones on. Hum from one channel. Infrared thermometer gun shows nothing gets hot, if the power supply diodes all renewed get a little warm. Let it sit with power to see what happens. Nothing really, if no sound plays. Did the outputs get trashed? Not this time which at least is Hope. But it doesn't play music if the lights work. Not re-resistored the Preamp as that seemed fine, but maybe it's not. It'll get that redone & try again. Not to give up as you need to see what causes the problem. If this was a Customer's amp it'd be difficult as the amount of work into this is about 2-3 times a typical rebuild & we'd have to see if the cuistomer wanted to continue or give up, if here the rebuild & repair is way too high. This is the difficulty with non-working amps. Some amps sold as "not working" can be easy or hard to get fixed, it's really a gamble on any Vintage Amp really if the Success Rate is very high, over 90% of amps work out & become safe & reliable for Daily Use. But those that don't have to be considered as part of the Repair-Rebuild game. No way are we breaking this SX-1000TDF as we wanted to keep an Early Pioneer as they sound so nice. It's a Challenge. Pioneer W15-031 earlier Tone Board isn't on any manual we have if we found the Circuit online somewhere, but the Board Layout isn't shown so one to work out, which as always takes time. Preamp new resistors, still the same. Absolutely Nothing wrong to circuit. Can only assume it was wired up wrongly, explaining how new it looks inside, did find a pulled wire on the Tuner for ground if oddly 5mm away from the point & aged suggests more a wiring manufacture thing. Going into the World of "Built Wrongly" is a very different issue. In the early 1970s people did complain of Faulty Goods being sold, HFN mag has letters describing faults of manufacture.


We Get Questions: Speakers Difficult To Drive.
Despite putting "Don't Ask For Free Advice" they just ignore it & ask questions like we know every amp or speaker made, with a slight offer of a chance they might buy. Speakers that are Hard to Drive are lousy ones, the designer has not tested them right & impedance will dip to 2 ohm or even 1 ohm even at certain frequencies. These Speakers will wreck amps as they are driven too hard. If the impedance goes very low at the deep bass frequencies it'll trip up Valve Amps. The speaker mentioned is Oskar Heil Kithara Loudspeaker a 2004 review online shows they are $4900 a pair, 94dB, but no real stats as in impedance beyond "4 ohms". These Ego-Named type of brands we know with Tim De P amps to 'not be as good as they should'. Guru types who create a 'perfection' to specs but not sound or useability. What Amp to Use the writer asks. No idea. Oskar Heil invented the FET, to us a pretty useless item as, to us, it has no place in Hifi as the 1971 Sony that have FETs are far inferior to Transistors & then the Tedious Hype of the MOSFET, starting with 1975 Sony V-FET outputs being described vaguely in a Nov 1975 Sony ad for TA-8650 & TA-5650 as "These Vertical Field Effect Transistors help deliver a more faithful sound than ordinary transistor amplfiers". It's Fluff Talk with No Proof as there can Be No Proof, Hifi is often Fashion-Led. Try to buy a V-FET transistor today, they were likely obsolete by 1977 whereas the 'humble' Transistor like a 2N3055 first around in the mid-late 1960s is still easily bought as it's reliable. Our Reply: No idea, Keep trying other amps, buy our Marantz 2385 as it's 185w is the only advice. But to note the Country a person writes from, they're just fishing for advice based on us supposedly knowing all Hifi, so why go deep into a reply. One similarly asking is in USA, they agree their amp needs a rebuild but "it's hard to find a good tech" is a bit insulting when they are messaging one in UK who can do the job. We had a silly person on ebay asking if our high grade vinyl was warped, again insulting based on other sellers ways, when we note all faults, item thankfully sells to another. If You Want Free Hi-Fi Advice... Go To A Hi-Fi Forum & Take Your Chances With Amateur Info.


Buying Hi-Fi Online. What Do You Get? Rogers Cadet III.

A customer bought a Rogers HG88 III based on our recommendation of how Great the last one we rebuilt sounded. They buy from a Seller with 800+ Hifi items, to ignore the 'strange' feedback knowing the item is Keep or Return. For some reason they send the Cadet III, the box is too light obviously but to sign for it as another amp expected. Both are described as "serviced & in good working order". Pics show HG88 is a high grade one, if the Cadet has browned coupling caps so will be well used. To see any sign of "Serviced" beyond axial caps amateurishly replaced with radials in a few places is nothing Servcied to us & could be 10-20 year old repairs. How they send the wrong amp is a mystery & so far they're not hurrying to resolve the issue. Rogers Cadet III is a 1965-66 10w 'Budget' Integrated Valve amp. It's quite modest in output transformer size & the main caps to recap would be very difficult for limited space & the original caps being multiple caps in one can. These based on ones we've cut open are now dried out totally, ready to drop voltages or short to trash the amp. Some "Experts" see these are still good as they've not leaked, but they've dried out. As the HG88 isn't here, why not just get a free try of a 50+ year old amp, just as a buyer would get if they paid the £400 which is a bit high if auctions see these sometimes go £300+, if what the buyer thinks of it is what we'll find. Last Cadet III we had was the 2 part one in 2012 & it had problems after some use. Box Opening. Photo shows it's complete with a good case, if certainly well used. The inside is very aged & dirty on the top floor, to say that is "serviced" is outright lying. Dirt on the front panel & controls, it's just attic find grade if complete, but certainly not worth anything like the price. Typical worthless PAT test sticker. Old mains cable with red & black should be rewired really, if it has a correct 3A fuse. Dirty inside top is bad, if the valve base holders are filthy especially the preamp ones, water splash stains inside. Amateur repairs using radial (= end) caps instead of axial (-[]- ends). Certainly has got slightly wet to have stain marks underneath & volume control case looks crusty, attic leak type. The Main caps are original, going from the double cap back one, single cap one then two double caps, you have 7 capacitors in 4 cans. Big blob of wax on underside of transformer isn't good to see as it will have overheated at some point, or used unventilated. Valves are wrapped separately, if we don't fancy powering it up if it'll work, it certainly will be aged sounding. The last HG88 III even with TV guy type recapping sounded thin, blurry & rather awful as original, the last Cadet III we had was very trebly with a grainy weak bass sound. Has all the correct base case screws as these are Imperial thread ones. "Serviced" here is still filthy inside, a few TV grade repairs, it really no better than Attic Find grade. To see why these are bought & swiftly sold on as they will sound awful unless properly upgraded. We didn't want to plug it in, if in general terms it's a decent attic find grade worth about £250-£300 tops. To a Buyer getting this, they'd put the Valves in, if they actually knew where to put them & find an aged tired amp, not be impressed at all & put it on ebay to sell. It would take us a few hours to properly Service & Examine before we even plugged it in & still being aware the Main Caps are all dried out, we'd not trust it on Speakers. We wouldn't send a customer the amp knowing the caps are all bad, this is why we've not tried a Cadet III since 2012 knowing the 7 cap stages would be a pain to redo. Therefore on seeing this, a Rogers Cadet III that is now up to 53 years old is Not a Recommended Buy. the HG88 III we Do Recommend, but only once rebuilt as it is the best one to redo.


1974-1975 Cost Cutting At Comet Hi-Fi Retailer.
We've mentioned often about Cost Cutting by Hifi Discounters like Comet & several other less well known Shops that even undercut Comet. Cost Cutting starts to show by 1972 in some brands & by 1974 the overall Quality had taken a big dip in nearly all brands, if some of those brands had got back into higher quality amps, but still priced a lot less than Marantz or Yamaha who seemed to have avoided Comet. Some early Comet brands later decided to not be in Discount stores, if there are quite a few names that fade in the early 1970s like Rogers & Leak. Nov 1974 HFN/RR is a huge issue over 300 pages, mostly ads. To see the Brands they list over the Whole Range of Hi-Fi is a bit telling, it means these brands were Cost Cut to fit in the Comet range. Comet did get good reviews & the shops were popular, the buyers got what they wanted in price paid plus Comet did have sales staff if not Demo Rooms. Brands featured are Akai, big dip in case quality on the 1973 AA 5800 range, Alba, Amstrad who had multi page ads of their own so clearly sold lots if very few are around for sale as quality wasn't high, Ferrograph still with their 1968 design amp, Goodmans, then some expensive Galactron Mk 16 preamp & Mk 100 Power Amp, not heard of those before. Keletron, Leak still with the Stereo 30 & 70, plus 2100 & 2200. Metrosound, Philips, Solarvox, Tandberg & Wharfedale. Three Big Brands though, Pioneer, Rotel & Sansui which are very penny pinched on spec, as made they are generally disappinting even those with No ICs, if the designs are still good to upgrade. Other Categories beyond Amps & Receivers are Grundig, Salora, in turntables Connoisseur, Garrard, Goldring, McDonald (BSR) & Thorens. The RRP prices are quoted if no shop sells at that price, old style lying to make it seem cheaper, eg Pioneer QX 949 4ch Receiver RRP £572, Comet Price £379 if other shops will undercut. It just brings greed out & manufacturers have to cut costs or go broke. Note no Marantz, Yamaha. JVC, Sugden or Sony plus other small brands missing. Comet offer to undercut any advertised price too & do have items in stock. The big Pioneer SX-1010 100w receiver RRP £458, Comet £309 is clearly far too cheap for a 100w receiver, should be around £500 if the quality was there. Nov 1975 HFN/RR just under 300 pages. Comet has a huge section p232-251 so 20 pages, shows how big they got after 9 pages in the Nov 1974. Pioneer QRX 949 now RRP £695 Comet £472 is an interesting increase, but to rember VAT had gone 8% to 20% over that time. Seem to have lost a few Amp brands so Akai, Alba, Bush-Arena, Ferrograph, Goodmans, Galactron again listed as Goodmans if they are hardly the same as HFE says they are an Italian firm, the styling looks European. Leak as it fades away 2200 only, Pioneer, Rotel, Sansui & Solavox. Akai onto the even more Cost Cut AA-1030 receiver, we had one & thought it very ordinary. Cassette Decks were still the Top Loaders, the Front Loader types not far away. Sansui AU 7700 "110w" amp RRP £240, Comet £190 seems very cheap for what it was, but it's 55w + 55w really which is deliberately misleading. Sansui AU-2200 boasts about being "All ICs" RRP £80, Comet £63 is very cheap & why all the small UK brands died away, they couldn't give the quality for the money. Plainest looking amp if still looks better than Amstrad, "30w" says the ad, 15w+15w, but HFE says 10w as does the Manual if 13w+13w at 1kHz. Manual shows it is All ICs, not one transistor, very basic everything & the lazy Zener Diode save making a power supply. Oddly still drawn by the Sansui 3000 1966 artist, they must have been sad to see such basic IC junk under the Sansui name. STK amp blocks are rubbish, they are so low spec, turn it up loud & it's just a fuzz of noise as it's such junk. Ah, but Your Hifi Prize for £63 inc VAT, fooled buyers still thinking Sansui was quality & "yes it's that cheap, Mother". Quality Dipped very fast in reality, who knew? As with seeing how life started to change hugely around 1990-92, only in later years do you see the downward changes. Customers still thought they were getting Good Stuff but were being sold "only what they paid for".


The Joy Of "Audio T" in 1975 Hifi News/RR Adverts.
They stirred things up in an ad saying, by review quotes that the Pioneer SA-9100 sounded "Foul". We've had this amp & found it a bit disappointing, as Comet had got Pioneer to sell too cheap, so Pioneer cost cut too much to undersell other brands. Blogs just previously mention Audio T again & having seen all their 1975 ads, they still have more to say, if give up by Dec 1975 & behave themselves. Honesty in Poor Sound was never mentioned before, HFN/RR did a Multiple speaker Review including for the First Time Subjective Opinions if made such a mess of it giving far too much Tech info, Readers wrote in saying they learnt nothing & were confused. Jan 75 Audio T start by saying old time Helpful Shops were dying, the big Largs shop couldn't compete & closed down only fairly recently. It's all about Money, but the truth from many letter writers these Non-Discount shops charging full RRP were so scared of customers getting a Free Demo & then going to buy at Comet they were often rude to buyers who went elsewhere anyway, explaining Largs closure. They say any Advice can't be trusted as Impartial, which always was the case in our Shop Buying days, they just wanted to sell easy bulk selling items or clear ex-demo gear that wasn't popular. Audio T a bit silly mouthing off, but it shows a reality of the era. They say the Lecson AP-1/AC-1 were not reliable but sounded good, if the company went broke soon after if got revived, again a Harman-Kardon HK-1000 cassette recorder isn't too reliable but good value. Breaking Down is no good to buyers, they'll avoid. Feb 75 ad is mostly the same as Jan, if they do alienate with their attitude a bit, wanting floor plans & photos to sell to mail order buyers, to not know if they are serious. Mar 75 gets more professional, at last. It tells they bench test gear they stock to be able to tell what is good & what is otherwise. Probably the First Time in a Hifi mag that it's said that Tests are not as Revealing as Listening to an amp. 0.01% THD is a worthless spec as only the THD which is 80dB below the loudest parts of music is measured. Distortion of the original sound is never revealed in it's whole, only the very low level floor. They rate the Yamaha CR-800 as well made & sounding good, we've had quite a few of these for that reason. They go on about measuring into a simulated load, ie an 8 ohm resistor, our Power Ratings page doesn't bother with adding a load as no speaker is an 8 ohm resistor or 8 ohm + 2µf to simulate an Electrostatic. They test parts of the amp to find where the "Foul" sound is. In reality either or all can be bad, Power Supply, Preamp or Power Amp. The Trouble with all of this is it just Confuses the Buyer who can only rely on opinion as many want Music not the Tech aspect of things. All Amps sound different, All Speakers sound different. Only tryting a few of each will you find a combination that suits you. Apr 75 Audio T carry on with their blah-blah if want you to bring in your "Foul" Pioneer Sa-9100 to compare to other amplifiers, can't imagine anyone would want their amp rubbished in what may be an attempt to sell you a better amp. They recommend the 'Transcriptors Reference' turntable, a faddish item that floats your LP on rubber points, instead of a mat that damps the LP, not a good idea. May 75 continues with more of the same, it musy have put customers off as they are far too Up Themselves, the easy-buy at Comet without the feeling you're an idiot buying the wrong thing. To us they really lose the plot by saying the Leak 2000 receiver is 'possibly the Best Receiver around'. We had a few of these early on, but never really upgraded one much as they are TV grade items with a thin very fizzy grainy sound. If Audio T think they are better than the Yamaha CR-800 they praised earlier, then forget it. Jun 75 just repeats May. Jul 75 goes in the later half of the mag now, previously they got in the first pages, if nothing new. Aug -Sep 75 shows a different angle, they offer 'Amplifier & Tuner' Clinics to get your item adjusted right. Trying to get customers in after alienating? Same ad in both. Oct 75 has them again try a different angle, by offering friendly demos of two speaker brands Celef & Spendor. Continued in the blog below the next one...


The Start Of The Less Is More Type Of Selling Those Certain UK Brands.

July 1975 HFN/RR has a Double Page advert by "Hi-Fi Corner" of Edinburgh. 'Clearly Better Hi-Fi" is their tag line. £1300 gives you "No Tone Controls, No Filters, No Speaker Controls, No Auto-Lift Device, No 16, 45 or 78rpm, No Speed Adjustment, No interchangeable Stylus Assembly". Plus a Free Hair Shirt & some Gruel too. No expensive User Controls that are wanted by Customers is what you get. Of course it's the UK branded crap that we detest for it's 'Lifestyle & Upgrade' options. Linn, Naim. SDT, Grace & Supex. £1300for Naim NAP 160 power amp, Linn Sondek LP12 turntable, SDT 180 transformer, for Linn we assume, Grace G707 arm, Supex SD 900E cartridge & Linn Isobarik DMS loudspeakers. All total unknowns beyond the LP12 in 1975, no features, only plat 33.3rpm LPs. Not exactly a system you'll use much as no features or adjustments to room or taste. Then to see the Name of who owns Hi-Fi Corner, your mate Russ Andrews. How well they hyped & paid Hifi Mags to promote this Hair Shirt Hifi & how many people have told us they wasted their time on this stuff for trying proper Vintage with All The Needed Extras. The amps are so basic inside, ICs & tightly wrapped unshielded cables. But soon the Hifi Implosion rates these things, Martin Colloms reviews them, Tim De P creates the Luxman overdesigned Pre-Power Monsters, The Specs Wars start. But Musical Enjoyment was the least interest, Audio T were right in saying this stuff sounded 'Foul', but they weren't taken seriously for having the right idea but outhing off too much so the Linn-Naim brigade swept in.


So What Did Audio T Promote In 1976-77 In Response To Linn-Naim?
A good question. Do Audio T agree with the Linn-Naim basic Cottage Industry ideas, or do they prefer the superior Japanese Hifi that is what most people are buying now. Jan 76 has BGW 250 amplifier & KEF 103 speaker, BGW a bit obscure if KEF certainly sold well over their ranges. Feb 76 gets a logo change & now they go for Quad 405 current dumping error signal strange amp, Sugden P51 & C51 power & pre, the ugliest Hifi ever, they are doing Themed Demos which if you can get into their Clique, were likely interesting events. Mar 76 again Quad with that ugly ESL 57 Electrostatic, who wanted ugly Leak gear in 1976, letters to HFN/RR tell that buyers don't like the old fashioned looks if dealers had to stock them to get the ESL which as time showed was a Cult speaker despite it's limits. Yamaha CT-7000 expensive 'best ever' tuner gets a mention, if what actual use was it in reality? Apr 76 has ESL speaker again being compared to the Spendor BC1, says women don't like the ugly Quad ESL, it does look like a 1950s heater. May 76 starts with "Believe It Or Not We Are A Shop" suggesting it was thought too exclusive. Here they promote a few brands & products, a sensible choice here & at last the typical reader might understand. Amcron the DC300A pro high power gear, BGW with 250B power amp & 202 pre seem to keep their interest if obscure to us. Dual turntables that are decent but clunky in use, Technics with the SL-150 shows we agree there. Yamaha the tuner plus a 'excellent design' on the Yamaha CR-200, if it's mostly a 1969 design as we have had one. Nakamichi for expensive cassette, Spendor, KEF & Monitor Audio for popular speakers of the era & stodgy old Sugden, "you may hate the looks..." Sugden one we had was nice sounding if too polite sounding. Jun-Jul 76 continues listing brands recommending ones budget to high, again the reader will know what they like & know where to start. Aug-Sep 76 has a messy big type ad of what they do plus a list of main brands. No interest here for Linn-Naim stuff is good to see. By Oct 76 they just do a generic ad, no different to any shop if listing no items or prices. Dec 76 gets Sugden A48 ugly orange fascia & Nextel crinkly lid paint thing. Probably sounds good but they age badly so we've avoided one. The amp is recommended with Rotel RA-812, Technics SU-3500 & Yamaha CA-600 being in the same league, note all are Japanese. Jan 77 gets the Monitor Audio ET 1000 turntable, a UK made Direct Drive, not the usual Belt Drive cheapness. Feb 77 has the JVC JA-S11 amplifier recommended 30w amp for £80 so expect ICs, if a decent Budget Buy really. Mar 77 has Spendor BC1 again & recommends Nakamichi 620 a 100w amplifier they recommend to go witrh the BC1. Apr-Jun 77 just has a half page generic ad. Jul 77 a full page ad, the half page one plus a general speaker section saying they have 40 pairs on demo. But the ads have lost any individuality. Aug 77 half page. Sep 77 no index & a quick look doesn't find them if Laskys & Comet are the big sellers now. Jump to Jan 80 & still the half page generic ad if the odd ad says more, but not the same now. Whoever the Firecracker at Audio T was, they've long gone. We found their approach to "Foul" Hifi interesting & as you can see they did do quite a lot to change the Hifi Scene, by telling more on the Subjective that led to changes in Hifi Reviews with dry opinions by Martin Colloms perhaps the first one to go Subjective. But the Public were content to buy cheap IC riddled junk & past 1974 there isn't that much quality except Yamaha which we helped Revive, in 2011 a Yamaha CR-1000 cost us £90 as these had no online opinions, we got lots of Yamaha to find their CR/CA x00 ranges their best & have had most. Interesting to follow a shop, but the market changed & they sadly faded away. Thankfully they promoted "Real Hi-Fi" not the awful Linn-Naim stuff that we never liked reading HFN/RR in the 1990s.


Fake Output Transistors Again. Ebay Seller Now Has Fakes If Long Trusted.
There are/were only three ebay sellers we trust for Transistors, they have helped a lot & send good stuff. You'd think they'd be able to get reliable suppliers for TO3 output transistors, most are £5 each, but a lot will be sold so the Fakers pick up on them. Our Yamaha CA-1000 got way overheated so to replace so much, so to think it running Class A in an enclosed space was why one main capacitor actually had leaked, to think best to replace the outputs. MJ15024 & MJ15025 are ones we've bought often with no problems, Google tells of problems. The thing here is You Trust The Seller. The "On" brand ones arrive, print looks a bit weak on the "150" if genuine ones can have weak print, but again You Trust. But they were fakes. The cases looked right, they made the right sound on dropping on the desk, unlike the last Fakes as blogged a while back. Two burnt resistors after 10 secs on gets power off very fast but it burnt the board, if not hard to repair & the burn dents are hidden by new resistors. The transistors were totally trashed, shorted or open circuit suggesting 20v & 5w innards to fail as fast as that, if no case melting here. Shows you How Alone you are even after trusting the seller for years. The 'On' Fakes have "BM1828 & "BM0945" respectively, big date gap but not matched pairs. The metal looks spot on, but now you just don't trust for these except Farnell or RS. The ebay sellers can be good for obsolete transistors, but current ones that are £10 for two clearly you can't trust them anymore, if years of buying trust is now gone. Ebay is useful for odd parts instead of putting a big order in which we do only so often. Within 30 mins of the Fakes Damage the amp worked using 2 of the original transistors again. For Supplying Fake Goods the seller has Liability to correct the damage, last one they paid up, if this one is to be seen what they do, they cheat in the usual way these days. Not to put seller names on our site though, but ebay lets them get away with refunding so the Feedback telling they supply Fakes goes, ebay is known to do this to hide Fake Goods are sold on their risky site. You're on your own aren't you? Currently Made TO3 High Power Transistors. Do NOT Trust To Buy These On ebay From Any Seller. We now trust only RS Online, Farnell & Cricklewood Electronics as Genuine suppliers on currently made Power Transistors. Ordered the MJs afresh from Farnell, they arrive in card boxes with very recent '18' year codes. This bad ebay seller is a scammer to refuse to pay a very modest £40 repair & for supplying Fake Goods should know about Fake Transistors, but they have the cheek to say "you test them before use". You just learn who you can trust is the reality.


Rogers HG88 III: What Do You Get Buying One Online.
We finally got the seller mentioned above to deliver the HG88 when they misdelivered the Cadet. It took telling them how to do it, send us a Courier label so we have proof it was returned. This was sold as "Very Nice, Serviced". Pics showed dust, but we saw all the right parts in place & otherwise worth our customer getting for our Rebuild & Upgrades. Easy enough you'd think for how it'd arrive. What we see as their "Serviced" wasn't even cleaned on any contacts etc. Old repairs on several small capacitors & resistors. Amp in the case the wrong way with missing screws & feet. Trace of old capacitor leak left marks on the lid base & on the underside of the amp floor. Valves a mix of original, ECC807 supposedly if no print, one rather darkened Tungsram & a replaced one only marked 'Poland'. The ECC807 fitted fine, the ECL86 were rather loose & needed swapping around to get a tight fit. Valves wrapped separately, if how would a buyer know where 8 valves went? Mains cable replaced & the Live-Neutral wires soldered on a very wobbly tag strip, actually it could be pressed 5mm to touch the Live to the Casing, yet the worthless PAT label allows a pass. Common Sense is Advanced Safety Sense it seems. Plug 3A fuse & wired fine otherwise. Bit of black tape inside the case to isolate the dodgy mains & we plugged it in. Loud hum on one channel, we use a Headphone box on the speaker outputs, hum fades if still a noticeable Hum on playing Music which it did on both channels. We only tried it briefly, L+R channels were not the same volume, the hum & a wobbly wallowy sound were not very nice. Their 'Very nice serviced' is sadly what Professional Dealers think is ok, all 1960s valve amps are very tired as they are naturally old. If you bought it & heard the Hum, you'd send it back, if what are you buying 53 year old valve amps for if not expecting to Rebuild them? As a piece of Hifi to use, it works but beyond that isn't suitable to use, we didn't trust it for more than 2 mins, it is pretty useless as-is therefore. Others may trust it, but the Hum is too loud. As an amp to Rebuild as the idea was, it's a good clean one & will rebuild well, if at a price that puts the Buy Price into a high figure, if once you heard it rebuilt, well worth the money. Just don't buy pre 1970s Hifi expecting to use it. Needs rebuilding is the only option for safety. Of course the Seller overprices the amp, but for the amp being otherwise decent to Rebuild, to buy it as many are corroded & much messed with. This one had the Cadmium 'gold' plated insides, usually there are just lightly plated steel. Great Buy to rebuild. Bad Buy to return if you actually thought a 53 year old valve amp is Plug & Play.


August 2019 Blog

The Joy Of A Bridged Amplifier.

We first heard of Bridged Amps with Exotic 1990s type High Power Amps. the reason why such an amp was needed was never explained, just that a 100w Stereo Amp could be Bridged to a 200w one. Not of much use really to Domestic Use, beyond Bragging Rights. We had a 1995 Spectral DMV-30 & DMA-90 pre power in 2017 as reviewed, one of those 'Disposable' Big Money Amps that can't be repaired for PCB type. It was Bridgable, we saw it had a swich that altered the inputs, but the Manual we were sent with it didn't say too clearly how to Bridge, so early opportunity missed for not wanting to half guess it. Couldn't see any Audio benefit & the owner said it sounded better not Bridged, if the Speaker Outputs seemed vague. In 2018 we got a 1973 4ch Marantz 4070 as much written about. 4ch bridges to 2ch & it's one of th 'proper' bridging amps as blogged earlier. But just as we sold the 1984 Sansui AU-G90X we found it was a Bridged Design, their "X" circuitry was a version of Bridging, if it didn't match our Tannoys so we sold it. Then we got the Trio-Kenwood KR-6340 4ch receiver just to see what another one was like. Very clean sounding but the Tone stage wasn't great so we just put it for sale & left it 6 months before trying it again. With lots of upgrades it now sounds awesome. So What Is Bridging Doing? It has No Ground Reference, it's like a 'clamshell' of Audio Signal, the AU-G90X calls it "Hot" on the + and "Cold" on the --. We found you can't test the output of a Bridged Amp with a Mains Powered & Grounded Oscilloscope, it gives a ground reference that you don't want, but to use a Battery Velleman one, you can see there is Signal on Both of the speaker outputs, Red has Signal & Black as it is now a reversed phase signal is there too. Your Speaker is driven 'Balanced' with No Ground Reference. No Live & Return, it's Signal on Both Outputs. The 4ch amps in Bridged Mode use one of the L channel amps as regular & invert the signal to the other L channel & the same for the R channels. To bridge a regular Stereo amp could be done, but you need extra circuitry & it might just trash your amp too, so best stick to purpose made ones. Bridging in Technical Terms halves the Damping Factor. Much more on wikipedia, search "Bridged Amplifier". They call it a BTL amplifier as do 1973 amps, Bridge Tied Load, if that sounds more like a Transportation term. From Wikipedia: "A bridge-tied load (BTL), also known as bridged transformerless and bridged mono, is an output configuration for audio amplifiers, a form of impedance bridging used mainly in professional audio & car applications. The two channels of a stereo amplifier are fed the same monaural audio signal, with one channel's electrical polarity reversed. A loudspeaker is connected between the two amplifier outputs, bridging the output terminals. This doubles the available voltage swing at the load compared with the same amplifier used without bridging. The configuration is most often used for subwoofers." Wikipedia is trusted on Tech pages. That sums up what we've put really. Bridged gives bigger Voltage Peaks on Dynamic signal source, such as Deep Bass on TV earlier today, it rattled a cabinet nearby, we've never heard any amp do that before. All isn't really that Instantly Wonderful though, the rest of the amp has to be optimal, the KR-6340 is with the Passive Tone & a lot more upgraded. The Marantz 4070 has a taste of the KR-6340 Upgraded sound, if the 4ch power is less than the KR-6340. There are high power 4ch amps like the Marantz 4400, if Marantz gear is often hugely priced yet not selling. As blogged before about the 4ch Trio-Kenwood, the Bridged Design that the KR-6340 & Marantz 4070 isn't in all amplifiers, first seen in 1973 if not all 4ch amps do 2ch either. You'd need to understand circuits to pick out the Good Bridged Designs compared to poor ones like the Leak 2000 uses.


Which Is Best: Bridged or Parallel Outputs?

Bridged gives double the Voltage gain so Dynamics on the 'right amp' are much huger. Kicking with 2 legs instead of one, Kicks Like A Mule, if the mule needs a lot of power to do this right, else he falls over after. Bridged is an amp you'll hear & find others then a bit lacking, after all the Trio-Kenwood KR-6340 just has upgrade ideas as put into many other amps. The 1969 Trio-Kenwood KA-6000 we put Parallel Output transistors as the Heatsinks have an extra space for when the design had to use Doubled Outputs to get the Power Rating, not used in retail versions, Higher Power output transistors covered that, if the Benefits of Parallel Outputs wasn't really understood in Hifi terms in 1969 in how to exploit the extra current. Parallel Outputs can drive difficult speakers better as they can create the extra current needed. But only a few Vintage Amps have Doubled Outputs as blogged before, ie Sony TA-1120(A) & Akai AA-8500. Parallelled Outputs in 2 or 3 pairs, even 4 in some Monster amps gives more Current if Sound is more Voltage Gain, the Current Gain gives it more weight. There will be Bridged Parallel Output Amps in more recent years if they'll be very tamed as too scary, Wikipedia says these are used in ICs which are by their nature tamed. Which Sounds Best? We have KR-6340 Bridged, KA-6000 Paralleled on our design plus the Marantz 2385 has triple parallel outputs. All drive the 15" Tannoy Golds that are 50w rated, to use the 185w Marantz carefully, if in reality it likely never uses more than 10w for our use. The KR-6340 with the Bass Kick as blogged just above shows it's putting out possibly 20w for that Bass peak. More Current sounds Richer, More Voltage has Bigger Dynamics. For most speakers Paralleled won't show that much difference if it is noticeable, the Bridged will give Bigger Dynamics. 100w Bridged is more Dynamic than 100w Paralleled. We put the KR-6340 aside to try one of the Paralleled Amps, the 2385 & found ourselves 'quite lost' without the Bridged sound, if it is clean & fast with fast treble, solid midrange good bass. We'll try the KA-6000 next to compare further. This has a rich sound, midrange a little more upfront, bass is nice, if treble is a little slow, this could be for the Power Supply pulling from the main 95v HT via a hot resistor to drop voltages, rather than a Regulated Preamp power supply, a thing we've thought before about that Amp. It's next version the KA-6004 has the 2 windings power supply, this only has one. Helps decide which amps to sell rather than do too much upgrading, the 4ch Bridged KR-6340 is the one we prefer.


What Did Trio-Kenwood Do After KA-6004, KA-8004 & KR-6340 Range? 

Already looked at that Aug 2018 section about Amps & Receivers. Their "Model 600" 130w amp has too many FETs in the preamp, the Sony TA-2000F shows FETs are useless in a preamp. But the Trio-Kenwood KA-8300 is 80w, KA-7300 is 65w & KA-6300 is 55w. But this is a 1975 range, the risk of ICs as Hifi after 1973 starts to get too cost-cut as many other Brands reveal, except Yamaha. KA-7300 already looked at, nice build quality but a hopeless IC output block. TVK site shows pics & it's a very plain looking amp, see where costs were cut. KA-8300 we looked at in 2017 & sadly it's the IC output block, so useless to us. KA-6300 we've not looked at before, if HFE doesn't have the manual still is why. Has power meters on the fascia as do the other models, KA-8300 has 2 transformers for the Dual Mono idea which is only as good as the rest of the circuit, Odds are KA-6300 is with the Darlington IC block, so really Trio-Kenwood lose the quality if the "Model 500-600-650" try to go without the ICs but FETs in the preamp with that Class B design isn't very good. If this was a USA site, we'd put "Trio Sucked" after the 1971-73 era. The KA-6000 may be a bit crude in some ways, but it's a genuine great amp if it's single Secondary Transformer winding unlike the KA-6004 just holds it back.


Courier Damaged The Amp, Can We Get A Repair Quote From You.

Well it's good they think a repair quote from us would get an insurance payout. But as we don't feather other's nests or ever would get involved with other's issues, we are here to sell Hifi & Records, or Rebuild-Repair-Upgrade Hifi. Message deleted if the cheek of it needs a blog. They packed a Marantz 4ch amp badly & it supposedly broke the power switch. But they also say they can fix it themselves, so what's in it for us? Nothing. The old game of getting a quote yet giving no job to the one who quoted is ridiculous, it's insulting. Interestingly we see the 4230 sold as "Spares-Repairs" on ebay sold for £151. 4x 12w & 2x 30w, probably the same one we had in the early 1990s. Power switch is in the upper black section on the right, not on the lower chassis, so how it got broken is likely a bit 'unusual'. What they should do is take it back as damaged from the customer, fix it as they suggest they can, yet they sold a slighly tatty if working 1973 amp needing repairs & relist it. We know the Courier payout game & for all we know they are doing a claim for sending it out damaged. Not to get involved at all, especially for no job. If we were asked to rebuild the amp & had it sent here, that would be a quoted job, but with missing & broken bits, it's a job to find the needed parts which makes it a likely 'can't get the parts' job that we'd not accept. The 4230 we didn't see on ebay, if it's a good one to buy, missing bits we'd pass on it. No-one will give you a insurance repair quote knowing "you can fix it yourself", don't try it on is the tamed opinion.


Vintage Amplifiers Stored For Decades In The Attic.

It's nice to get One-User amps. often the pre 1977 ones were just put up in the Attic, usually uncovered, if sometimes put back in the box. In the 1970s the idea from what years later reveal, storing away Hifi items is common. They were supposedly replaced by "something better" if by 1977 the quality in Hifi was very different to pre 1974 as said many times by us. To get an amp full of dust, dead spiders & webs plus 'attic patina' is very usual. amps past 1977 stayed used into the 1980s & from ones we've had, were usually stored in cupboards or forgotten on shelves. 1960s & 1970s UK Hifi buyers could by a House in those days, a Detached or Semi-Detatched has an attic & older properties had a cellar too. Big Sheds were common too & these got filled with abandoned but not thrown away electronics. We had a 1972 Sony TA-1140 amplifier put back in the box, but the attic must have leaked for years so box half rotted away. Amp was a bit 'aged' looking but surprisingly cleaned up nicely so you'd never know. That's the problem, what is in the Attic or Loft of a House? Water Tanks to give Cold Water but be off the mains water supply, all a nuisance now after decades aging, but the ways of the time. An Attic is open to the air by the eaves, holes open to ventilate, if hopefully keep Squirrels out. The attic gets the full heat of the Summer, the full cold of the winter plus all the damp air & bugs crawling about. All this does age the metal in the amplifier, leaving crusty amp cases on ones even Cadmium plated or Painted. Amps with lots of push in connectors etc will age similarly, all needs cleaning & servicing. Forty Hot Summers & Cold Winters does age an amp if as long as it's dry it'll still be salvageable. It's a bit amazing what amps we've had that were abandoned, the 1979 Luxman LX33 was an attic find for 'attic patina' inside. The seller of that had no idea & said it made screetchy noises so sold it off cheaply. Other amps raw from a 40 year sleep are understandably in poor condiotion Service-Wise. As we put in the Sansui 4ch section above, some think a cheap job will get them going again, the reality is any long abandoned amp left to the elements in the Hot-Cold-Damp of an Attic needs a deep going through to get it playing right. Capacitors unused for 40 years might reform a bit to sound acceptable, but we found a long stored 1977 Rotel RX-1603 Monster Receiver needing the huge main capacitors replacing as one has dried out so the amp sounded awful. Again it brings the fact a 1972 amp like the National Panasonic SA-6400X is still 47 years old, well past it's use by date. What will it need to be sellable?


Amp Butchers? Think You Can Remove"Bad Unwanted" Stages In An Amplifier?
The Amplifier Stages we don't like in some amps to write this blog are the Filter & Muting Stages. Tone Stages are needed, these are useful features. If you have no need for Tone, Filters or Loudness, try to buy an amp without these. But we won't remove them, it's not what a customer wants in buying Vintage, they want the amp complete. To Butcher an amp for your own needs is you choice, but it'll make the amp worthless beyond parts. To understand what the "unwanted stages" are doing is required. Acceptable Passive Filters such as on the Sony STR-6120 has a Filter Stage with what look like limiting values, if in reality these act more like a Buffer rather than to reduce the volume. Fisher 1960s Amps use even bigger values if again they don't seem to adversely affect the sound level or overall quality, so leave them alone, we've tried & can tell they aren't a problem. Unacceptable Passive Filters are the nasty passive "T" Bass filter, like 1967 Pioneer have, the 1965 Sony TA-1120 has one as do several 1970 era Sansui & the NAD 160(a). To get rid of permanent filters like these is fine, an acceptable part of upgrading, awful harsh bass filtering design that affects the sound severely is unwanted, see an earlier blog about the 1967 Pioneer SX-1000TDF & how it sounded as original. The harsh Bass limiting makes bass a vague mess, it should not be in any amp. Active Filter Stages are not good design, yet often used & designed badly, this means the Filter Stage has Transistors as gain or buffers. These can affect the sound for Overdesign & high gain that must be reduced with heavy NFB. Why they are even used is a mystery & to redesign them is extra difficult, if possible. You Can't Generalise An Idea You See In Another Amp To Put Into Another Amp, Similarly Upgrades We Do Are Different For Every Amp. But you have a good amp that you want to be different. The Best Advice is Sell It before you butcher it. To only alter what is subtle, or easily put back. To try to bypass an unwanted stage in an amplfier doesn't work out for different audio levels, hum, instability, excess RF & impedance differences. You generally can not remove any circuitry to "better" the amp, it just doesn't work. A Future User Or Potential Buyer Would Not Be Pleased An Original Feature Was Gone Or Not Operating. Much Hifi can be improved by keeping the design original, if plenty improve for some redesign. What we do is SUBTLE Recapping & Upgrading including Redesign, as our Solds Gallery shows. Tried & Tested ideas go into Customer's Amp, Experimenting is on Our Amps & we do sell these once we've finished upgrading & they are Reliable to sell. To present a Quality Rebuild. that's still got Originality is what buyers like.


4ch: What Are The Good 4ch Bridged Amp Designs Then? 
Best way to see what 4ch Quadraphonic Amps & Receivers are is to look in the Hifi Year Books, in similar style to the List of Amps & Receivers pages. 1973 is the first book that lists these, so to pick through to find the better ones, ignoring cheap ones or part units to add on to others & then look at the circuits, if findable. Must be 15w or more to be worth considering, there were several 4x 10w & 12w ones, if 4x 15w is our mimimum here, if that omits ones that look promising so we add some. Ignoring 4channel-only ones, must have a 2 and 4 Channel Wattage to show it's Bridgable. Probably won't leave many really. Whether the ones stated are 2 & 4 channel are bridgeable is to be found out.

•1973 Quadraphonics. Starts with early looking JVC both are 2 & 4ch MCA-V5E Amp "15w" £85; MCA V-9E Amp 25w x4, 55w x 2 £140. Also MCA V-7E 25w x2, 12.5w x4. Pioneer have some but both stated as 4ch only, QA-800 is 34w £179, QX-8000 receiver 32w into 4 ohms £237. Sansui are 4ch only with QR-1500 15w x4 £183, QR-4500 27w x4 £367. Trio-Kenwood has a 2ch amp that's in the wrong section, KR-6170. That's it, if other 4ch complete systems of Low Power.

•1974 Quadraphonics. Adds Akai AA-8100S 36w x 2, 18w x 4 £265; JVC have a lot: 4VN-880 28w 'per channel' amp £170; 4VN-990 38w 'per channel' brideable amp (see our review) £236; 4MM-1000 a 10w receiver with Marconi dials £229, 4VR-1006 10w £229; 4VR-5414 15w £229; 4VR-5545 21w £308, all 4VR are receivers if seem 4ch only. 4VN-550 12.5w amp. Marantz 2440 20w 4ch receiver £165; 4060 15w 4ch amp; 4100 25w x 4 + 60w x2 £286; 4415 is a 15w x4 receiver £236; 4430 30w x 4 receiver, only the 4100 is bridgeable. Onkyo Y-3A 16w x4 receiver £133. Rotel RX154A 10w x4 receiver £122 this one seen a few times on ebay as a budget buy as new. Sansui QS-500 33w x 4 £157 + VAT; QR-1500. Sony have a decoder & extra low power 2 ch amp to add to your main amp, SQA-100 & SQA-200, if not proper amps.

•1975 Surround Sound is the renamed section. But that's just add-ons. The 4ch Amps & Receivers are put in the main Amp & Receiver sections. To rake through looking for 4ch gear. Amps section: JVC; Marantz; Radford HD-224SQ appears to be the Only UK 4ch Preamp; Servosound RC4-SQ preamp decoder is another UK one; Trio-Kenwood only shows the KSQ-400 add-on 4ch decoder with 8w power amps to add to a 2ch amp. Receivers section: JVC adds 4VR-5456 45w x 4 £385; 4VR-5446 22w x 4 £308. Marantz show no 4ch receivers. Mitsubishi show the DA-R400 as "40w RMS" but no further amp info or price, could be 10w x 4. National-Panasonic-Technics have SA6400X £255 & SA-6800X £340 but no info. Pioneer QX-646 10w x4; QX-747 25w x 4; QX-949 44w x 4 all seem to be 4ch only (see below) & not priced. Rotel RX-154A, RX-454 24w x 4 £217. Sansui QRX-5500 25w x 4. Trio-Kenwood don't list the KR-6340 range if the 6340 shows in shop ads as does the KR-8340.

•1976 4 Channel Amps & Receivers. Seeing how feeble these sections are, by 1976 Quadraphonic is seen as a Failure. Discount Stores start to list these amps & Receivers Cheaply, the 4ch ones Bridgeable to 2ch will have been a bargain buy at the time. Notice only a few Manufacturers bothered with 4ch. JVC same 3 amps; Marantz had 4060, 4070, 4100, 4140 amps, the 4070 is bridgeable, the 4060 is a 1971 design & isn't. JVC same receivers. Pioneer same. Rotel RX-454 only. Nat-Pan-Technics now just Technics with the same. Trio-Kenwood finally shows KR-6340 27w x 4, 65w x 2 £345 + VAT; KR-6340 20w x 4, 50w x2 £235 + VAT.

•1977 shows no JVC amps, Marantz 4070 & 4140. JVC still 3 receivers Pioneer 2 receivers. Rotel has a RX-254 which must be a late if optimistic new model. No Trio-Kenwood. 4ch failed & moved on if the discounters still had these. 4ch failed dismally for mixing too many Disc Standards, the fact who needs 4 channels where there is little to play on them beyond studio created mixes of Pink Floyd etc. The next Gimmick in Hifi was the Monster receivers then Pre-Power amps. The 4ch amps that are 4ch only aren't too much use, the Bridged Ones that more than Double the 4ch power need remembering & for us to see if are any as good as the Marantz 4070 & Trio-Kenwood KR-6340.


4ch: Looking At Three '4 Channel Receivers' On Ebay.
To have a look what's available on UK ebay. Probably all the Marantz are on USA ebay at high prices. JVC 4VR-5456 £400. Big item, proper TO3 outputs, sold as "Not Working" as it's too complex plus FM dead. 45w x 4 says HFYB if seller says 2x 100w & it does have "BTL" wording on the back. Interesting. Pioneer QX-949 £700 44w x 4 if looks 4ch only (read on). Nice looking amp with 4ch display section on the right. But Not Bridgeable? Technics SA-5600X £500 isn't one listed above, does appear to be Bridgeable if care on wiring speakers as it doesn't switch them inside, 2 wires to 'Red'. 25w x 2 if only 8.5w x 4 is their budget one. All look impressive, Technics the lower power one & vinyl wrap so despite an all Transistors amp with proper Bridging , not enough Power & way overpriced. Pioneer has a messy schematic in bits, looks 4ch only, if well made. One for the collectors only really, not much good to use & leave 2 channels unused. JVC is way more impressive, proper 100w x 2 Bridged. Has the SEA equalisers as for Front & Rear. 20kg with 513mm wide, 410mm deep & 180mm high, it's a Monster receiver. NFB on the preamp is typical JVC, Power Amps are a straightforward design. HT is 33v which is not much higher than the 27v of the KR-6340. Not a bad Bridged Amp, 100w RMS x 2 is likely underrated as is our KR-6340, if we'd not choose it over the KR-6340 for proper Tone controls & no Filters. JVC has issues, if £400 gets the best one of the three. Rebuild on a 1974 receiver is required & it's a big job as double the amp for 4 channels. There are more 4ch receivers than amps around to buy, so to look at 4ch receivers as a better chance of finding one.


4ch: What Good Are Non-Bridgeable 4ch Amplifiers?
Most 4ch amplifiers & receivers are 4ch only, without the BTL Bridged facility, it's not too obvious which ones are which explaining why we tried a 1972 National-Panasonic SA6400X. Info out there is misleading & often wrong. 1973 was the first Bridged Amp year, 6400X some sites say 1973 or 1974 which is wrong. A 4 channel amp has two Stereo amplifiers in it so even if you have no use for 4ch, then an amp like the 6400X is still useful as it has 2x 20w for Stereo if the 4x 20w of quadraphonic will go unused. Small amps with 4x 10w are of limited use, if 15w on amps of this era is still useful as the Yamaha CR-200 proves. The SA-6400 is a large sized receiver, looks great if the size of it for 20w x2 RMS appears a liitle low, the Nat-Pan amps have a better volume & presence. The only difficulty is some of these amps are Rare so getting Service Manuals isn't possible. Beware the pay-to-download pdf sites who think you'll wait 1-3 weeks for the manual. This sadly is a con as they use 3 weeks to try to get a manual & likely can't. The SA-6400 we'll recap ours to sell it, if without the Manual we miss learning the design used to get such a good sound, if perhaps it's not that different from other Nat-Pan of the era.


4ch: The Early 4-Channel JVC MCA-V range: 5E, 7E & 9E.
These look interesting. Proper Bridging if on the Amp Outputs with Diodes & Resistors plus using both "+" outputs to bridge. These have rotary Tone controls also. They look like the 1966-69 amps if they are proper Bridged Amps, MCA-V9E is 25w x4 & 55w x2. Aug 1972 HFN/RR reviews the JVC MCA-7E. Service Manual of the 7E found so have a look... 7E version withdrawn by Aug 72 for the new 9E version, if they'd done the review of the 7E still. JVC we've liked their 1966-67 ones & the 1976 JR-S 600 receiver still had the Good Sound, if the plain tin boxes by 1978 are with ICs so not our interest. The review is long & waffly, much drifting from the amp itself. Square Waves at 1kHz are spot on if 10kHz is a bit slow meaning it'll sound a bit soft. Proper Tone Controls make this nicer, the SEA is fine on the 1967 JVC 5040U we had recently, if a regular tone we prefer. Performance is said to be "good" and the amp "really excellent value for money" if typical dry reviews tell very little beyond that. 5E version has no meters plus a £89 buy, with £110 for the 7E & about £150 for the 9E. Looking at the 7E Circuits. All Transistors, NFB tone on 3 transistors, Phono on two. Power Amp much like the similar Receivers with the Bridging stage a switch before the Power Amp input as typical plus more after the Output Capacitor for the Meter & using the "+" connectors only for Bridging, it is similar to 1973 Trio-Kenwood if less sophisticated which may mean it's not too successful in 2ch. Power Supply is basic with only one HT winding for Pre & Power which isn't ideal. These amps not known, £82 bought a 7E which is a nice buy. The 9E is the high power one. would think they sound nice, if no 9E circuits findable on a quick look. Later 4ch amps like the JVC 4VN990 is a proper bridged amp, 4x 38w plus 2x 88w are impressive. 4VN-550 25w x2 + 12.5w x4; 4VN-770 30w x2 +12.5w x4; 4VN-880 55w x2 + 25w x4. This range first in the 1974 HFYB so a 1973 range. We later get the JVC 4VN990.


4ch: Technics 4 Channel Receivers, Any Good?
National - Panasonic - Technics are the same brand. HFE shows there are a few: SA-5600X mentioned above 8.5w x4, 25w x2; SA-6000 10w x4, 30w x2; SA-8000 13w x4, 36w x2, SA-8100 16w x4, 46w x2 & SA-8500X 28w x4, 80w x2. Hifi Yearbook kept those obscure, if 45 years later HFE has the info. Who would have even known to buy Technics? The turntables known, but National-Panasonic was the Amp-Receiver brand until about 1976. Service Manuals found but the big 8500X is too choppy to look at quickly. The 8000X version, the 'X' seems to be a slight facelift in design outside, has a better schematic. Designs look as good as the Trio-Kenwood & Marantz which we've had to Review & Blog on before. Complex to rebuild as double the amp, but Quality here, if not surprising as the 1967-72 National-Panasonic Receivers were pleasing. Seems early ones are National Panasonic & the later with the "X" are the Technics rebranded ones. SA-6400 exists 26w x 4 at 4 ohm & 20w x 4 at 8 ohm so to assume 50w-60w x2 at 8 ohm bridged (not so, 1972 model 4ch only), big amp 453mm wide much like the KR-6340 in size. Pic online shows it has a 2ch-4ch mode so as 1973 expect it to be a bridged amp like others mentioned here. The SA-6xxx range is SA-6000, SA-6200, SA-6400 & SA-6800 exist. SA-6500 is a 1971 Stereo receiver. The problem with specs on HFYB & online is they don't always show the Bridged ones, here most are Bridged, if the impressive SA-6400X we have is 4ch only. See below as it needs a blog.


4ch: Pioneer 4 Channel Receivers, Any Good?
Again HFE shows a few: QX-4000 10w x4, QX-646 10w x4, 11w x2, QX-747 20w x4, 40w x2, QX-747A slightly updated 1976 version, QX-8000 20w x4, 25w x2, QX-8000A updated, QX-949 40w x4, 60w x2, QX-949A updated, QX-9900 28w x4, 33w x2. The early 2ch-4ch ones from as early as 1971 have less impressive power ratings as shown, so it's not a proper bridged design like 1973 onwards. The ones that look proper bridged ones just by the power are QX-747(A) & QX-949(A). Bearing in mind Pioneer were in the Discount stores by the time of those two, what to find in the circuits? QX-949A has a service manual, the 949 schematic is too chopped on HFE. Stages before Transistor Tone are ICs for Phono, Mic & more ICs for the 4ch stages & Effects. Power Amp an odd design with limiters. Looks good otherwise if fear of Pioneer cost cutting probably hides a good sound.


4ch: Sansui 4 Channel Receivers, Any Good?
The Sansui QRX 6500 is on ebay Aug 2019 if to only see the front panel. This shows 4ch & 2ch options but looks more like a 4ch amp than Bridged. 4x 37w only, no 2ch bridged. Looking on HFE site Sansui went crazy on Quadraphonics with loads of 4ch Receivers, Eighteen of them is excessive, we thought JVC overdone it, yet these are not shown in the HFYB. QR-1500, QR-4500, QR-500, QR-6500 are 4ch only. QRX-2000 7w/11w, QRX-3000, QRX-3500, QRX-4500, QRX-5001, QRX-5500, QRX-5500A, QRX-6001, QRX-6500, QRX-7001, QRX-7500 25w/32w, QRX-7500A, QRX-8001 40w/100w, QRX-9001 60w/120w. Only a few are proper 2/4ch ones so to look further at those two highlighted. The rest are 4ch only. In 4ch Amplifiers more sensible with QA-5000 10w/14w, QA-6000 18w/40w, QA-7000 15w/40w. QS-800, QS-800A are add-on amps with decoders & 2 channel amps to put with another stereo amp. Again only two appear Bridged. Sansui were not wise making so many 4ch amps & the majority being 4ch only. QRX-9001 has 'BA 312' ICs in the Tone Stage & 4ch stages if otherwise all transistors in the Audio stages. Has a Dolby stage, 23kg Monster Receiver here. ICs much like the 'highly rated' Monster Receivers puts us off if the 9001 certainly is a complex huge amp, the power ratings suggest it's not really bridged, there is no "BTL" in the power ratings, if 60w to 120w is double, usually Bridged like other Brands would be higher, complex circuit to follow. 4ch version of the 9090DB & a 'Collectors' amp, one HFE commenter reckons just $300-$500 will get it going right, really? The amount of work in an amp like this is extreme if you want 'use daily' quality & done professionally. QA-7000 is the Amp, the manual says it is BTL connection aka Bridged explaining 15w x4 & 40w x2. QA-6000 appears not to be bridged, but it is BTL with 22w x4 & 45w x2 as specified, so some different methods used. We're only having a quick look, Sansui are a bit confused on ratings, the receivers are too big & with ICs. The 4ch amps being Bridged seem worthwhile if again the IC in the Tone. As with other later Sansui, the ICs do spoil it a bit as otherwise they seem good quality, if far too many models & all will be rare.


1973 JVC VR-5521 Receiver, What It Sounds Like To Us As Original.

We've had one of these before in 2015, as with all the amps we get it's an educated gamble just to see what they are like. The 2015 one was the 5521L version adding LW, this latest one is the USA 5521 version with FM/MW. Marked as 110v on the back if it's actually Multivoltage, the silver box over the typical Black Multivoltage block as shows on our Solds Gallery one. So we set it to UK 240v to save bothering with the step down transformer, if the USA customer will get it set to 110v again. Strange how both we've had were abandoned ones mucky inside, the looks must have seemed 'old fashioned' compared to the silver 1977 ranges so it gets put in the attic for decades. Fluff & leaf bits here plus a little water damage inside, if minor. Has had some use as not all the bulbs work. What Do We Hear As Raw Original? Crackly Controls as always, some hiss shows on the SEA Graphic Equaliser which is not like the Graphic EQ boxes of later years as this is passive beyond one gain transistor. The sound is respectable, not rough sounding, but rather flat with bass barely there & dynamic quite reduced. The overall JVC quality does shine through if it needs Our Upgrades to get the best from this 22w receiver. FM & AM works which is always the stumbling block with tuners, if in our experience most beyond 1967-69 Trio-Kenwood do work to a degree. Playing FM needing the SEA EQ it sounds decent if rather limited with a lumpy bass instead of Extended Bass. Trying Aux again playing louder to see if it has any kick, it sounds thin & harsh with no real body to the sound that it had played at lower volume. No doubt this is the real reason these JVC got abandoned. Try Guitar Rock, the usual Joan Jett hits, oh dear they sound thin & uncomfortable, hollow sounding with no guts to the sound, if in some ways the sound is clean, it just sounds unpleasant with no weight to the sound. We had the 1967 Sansui 400 recently, a 20w receiver. It similarly sounded lacking as original if having an overall quality to know better was in it, if we upgraded it as far as it could go to see how good it could be. It upgraded way better than we'd imagine if so much was rebuilt & redesigned, the lucky buyer of that said he'd never heard an amp that good. Because only we upgrade like we do & to be fair, not all amps can take it, but it's good to try the interesting amps to see how far they can go. JVC VR-5521 needs a $14 manual from Analog Alley, not all Manuals are free if they should be really to keep them alive, but the $14 one has their name all over it. The circuits of the 5521 show 2x Phono transistors, 2x Preamp Transistors inc the SEA stage, if only slight NFB unlike the earlier models. Power Amp is 6 transistors, input, driver, P-P drivers & P-P outputs, clean & sane design that gives an overall clean sound if needs quite a bit upgraded to hear it at it's best. Relay output on Semi Complimentary design, no Coupling Capacitors if no Differential either. Power Supply is modest with one Transformer winding giving Main HT & 2 Preamp-Tuner Regulators on ±28v. This amp can upgrade well if to still bear in mind 22w power has to 'keep within itself' to keep it stable. The design of the amp is a very good one, if it needs rather a lot upgraded to get the best out of it.


Stages Of Recapping And Upgrading.
To compare with The Car World perhaps, if new capacitors etc can be better than what was made in 1970, generally by 1980 the quality of today is mostly set, ignoring pointless "exotic" components that we don't bother with as they are no better in reality, which is again a bit Controversial, but what we use is proven by our usage to be high quality enough. "Restored" should be using the exact same spec, same resistor types, same transistors if needed & same capacitor values. New will better Old, if higher quality New Capacitors can cause issues for higher frequency response. There won't be any old-for-old compare unless you find NOS capacitors that are unused but aged, it doesn't really work. Upgraded in Car Terms is "Custom Upgraded", simply because it's Not Stock but is a sensitive Upgrade that looks right & offers an improvement. Not to be done lightly, upgrading is redesign & many issues can arise, if these can be tamed to keep a good reliable amp as we offer. This takes a lot of experimenting to get right & test right. It's far from Butchering an amp, as we've proved Customers Trust Our Amps, which is why we show the detailed phonos, anything less won't show the work done. Note "Sensitive Upgrade", anything beyond that takes too much of the original away. Custom Upgrade must still look from the outside as original & the functions should all still work. In Cars they call some Custom Cars "Resto Mods" if this from seeing on TV is old car outside, restored but with high performance innards. this isn't really comparable to Hifi & the idea is not a good one in Hifi. People buying say a Yamaha CR-1000 want the pretty looks, updated to be Use Daily with Worthwhile Upgrades, if sadly no-one else seems to be taking Our Lead on doing anything more than Basic Recapping. We keep looking...


The Hifi Scene 1975-1978 Seems A Mess In Hifi Magazines.
Reading the HFN/RR 1956-80 set again to be sure we didn't miss anything, the Hifi Scene appears to Lose Professionalism. The "Musicality" and "Cables Changing Amp Sound" stories are actually true, but it's all such a mess. Hifi News appears to have John Crabbe ill or away as a later issue tells for early 1977 quirks & he's left Two Hi-Fi Hippies in charge, Paul Messenger & Martin Colloms, both sporting Rock Haircuts & Hipster Beards. We Welcome them to a degree. PM with his "Subjective Sounds" is often pointless as he just looks at the UK Linn-Naim type stuff & MC gets weary trying to do extreme amount of very confusing tests on a group of 7 then 5 amplifiers. What the reader is supposed to understand is a mystery. The 5 Amps Test says the amps all test well yet no tests reveal why the Amps sound so Different on Subjective Tests. They don't realise the design & spec creates a good sound & from our exploits the difference altering just a few components can make to the sound of an amp would fry their minds. In late 1977 one letter writer comments on this, thinking that the old sober objective tests told all they needed to know & wishes the "Musicality" crowd would vanish. We look at Amps Subjectively then Objectively with Circuit Diagrams to see what can be Optimised. Anyone else do that? We see work others do to amps, by the amp being "rebuilt" but strangely Up For Sale as they don't like the Sound, because they've not Rebuilt it with Design Based Upgrades. The PM guy soon leaves HFN/RR when JC returns & says in as many words the magazine has been "Chaos" without him at the Editor post & we have to agree, if certain ideas have proved worthwhile, the HFN mag was now competing with "What Hi-Fi" and "Hifi Choice" as adverts show "Hifi Choice Best Buys". To us, by 1977 the Hifi scene we like has long gone, the 1965-73 era, just Eight Short Years has gone & most brands of quality are lesser versions of previous years, too reliant on ICs to get Worthless THD ratings, THD is Total Harmonic Distortion that can be 70-80dB below the Music Peaks, ie you'll not hear 0.1% or 0.001% as being any different. Cost Cutting yet again is why the Amp Quality dips, the amount of Silver Pioneer Clones with that samey fascia design & rubbishy insides putting all stages on one board. We do often look at ones post 1977 on ebay to see them & look at the circuits, but we don't buy them. Even Amstrad with their 'Executive' range, including the cabinet that started the Rack Mount one-piece disaster by 1979, are copying the Japanese look if on seeing they put tiny inside pics, the insides are still the same old rubbish. Look on ebay, try to find late 1970s Amstrad in good working order, you'll rarely see any as they were binned long ago, yet you find plenty of the Japanese amps as even budget ones were built to last.


Overdesign In Amplifiers Is A Problem Later Solved?
Hifi by 1975-77 has got to a Rut of the Worthless THD Ratings War of 0.01% being The Catch to hook a buyer. THD is as stated above, Total Harmonic Distortion that can be 70-80dB below the Music Peaks, ie you'll not hear 0.1% or 0.001% as being any different. It looks good on paper & it conveniently hides low spec design & cost cutting. As the Subjective Opinions that start showing 1976-77 in Hifi News, they are finding the Test specs aren't really telling anything of how good an amp sounds. They are finding Valve Amps have more "Musicality", which to us is a friendly sound of good balance but can be from a tired old amp as our 1932 Pye G/RG radiogram with it's 4w power and no NFB sounds ancient, but pleasing, if far from Hifi. The Blog Title, that we wondered what it meant re-reading this, here is the fact of adding more needless circuitry to get a "better sound" is fraught with danger, so lots of 'stoppers' are used, the low value ceramics that add a fizzy sound. The 1965 Sansui TR-707A is a remarkable amp, crazy design, all very carefully thought out if even as new, the manual says Aux & Phono are -70dB noise floor, the 1965 Sony TA-1120 has more design to get it to be -110dB which is a value that even today is impressive. But to get these -110dB Test Specs, there needs to be Overdesign which the TA-1120 does have as 'sound shaping' circuitry is evident, it gives perfect Square Waves, if we'd still like to redo one from scratch again, to our ideas. The 2007 Marantz PM 6002 once all the 100 pieces of dumbing down were either removed or altered, it has the similar Noise level as a 1970 amp, transistors are no quieter than 50 years ago. The 1969 Trio-Kenwood KA-6000 has not too good design in the Buffer Stage behind the Volume & poor design with Filters acting at full volume after the Volume Control. Our KA-6000 we got rid of both Buffer & Filters as they are too poor once the rest upgrades. Too Custom perhaps? Look how 'perfect' the TR-707A does High & Low Filters, yet no other amp uses this design. The TR-707A has Zero Stoppers in the design to tame spurious ultra frequency oscillations & peaks. It's Germaniums on all but the last 2 stages & we were wary of putting Silicons, if worked out fine when usually it doesn't. we need to try these things & Question all we see. The Yamaha CA-1000/CR-1000 has overdesign in the Filter Amp, so needs it's taming else as we've found, else it will knock out the Main Outputs for switching on certain stages. The Marantz 2385 with ICs that aren't particularly a problem in use still needs the stoppers to cut out bizarre noises & to go further into trying to upgrade the power amp could be quite risky so we've not gone too far. The More Circuitry Used, as in Active Transistor stages such as a Buffer or a Gain Stage to use NFB, the more taming the circuit needs. Usually this taming is excessive or poorly done to actually spoil the sound, or those nasty "T" Bass Filters as mentioned recently in a blog. An amp can be 2-3 transistors in Phono, 2-4 in Preamp-Tone & 6-10 in Power Amp. This actually describes the Sony STR-6120 with some other amps of lower power on the lower transistor counts. They sound great. But once Overdesign appears going over these amounts, the amp goes Unstable & there need to be varuios things done to tame the amp from trashing itself in normal use. That Marantz PM6002 was a 2007 amp so scared of not being universal so 100 "dumbed down" things were added is the extreme of Poor Design today. ICs are overdesign, sometimes with 8 to 20+ transistors doing what 2 to 3 regular transistors can do, so ICs need their taming as the Marantz 2385 revealed. But look what we've typed, a 1965 Sansui TR-707A is designed so well to not need any dumbing down. It needs a huge rebuild to be as good as ours is today is the stumbling block on this amp. Your PM6002 will be Bin Food already as the rubbishy tiny Volume Pots etc wear out & you can't get spares. The Quality of Build in the 1965-73 era amps we like means they are Forever Repairable, assuming they ever worked from new unlike our 2 year chore on a 1967 Pioneer SX-1000TDF.


The Joy Of Amplifier Comparing...?
Talking just about Amps we've recap-upgraded. Big Compare Sessons with amps we don't do now as it just confuses, the first amp has your ideal & other amps sound good or bad, but then pick a different reference amp that may have been not liked so much & then it shows up the other amps. We used to write opinions of amps & see how far wrong they were after a year of comparing plus further upgrading. They still All Sound Different. Which amp of say 6 amps is best? All of them, but they suit different moods. The Tonal Balance is what differs including how they Match to speakers. We put the Amps to test on a big coffee table-chest to test them, this sometimes brings up mechanical noise from the transformer. Beyond that we get Amps with Higher NFB like the Yamaha CA-1000 from 1973 they sound 'perfect' on Headphones after some alteration, yet on speakers played louder the amp for the NFB gives more 'texture' to the sound by bringing the sound more flat that enhances mid range detail. This we thought sounded very good. But next day watching TV for Breakfast, the amp was played quieter & all the sounds sounded too compressed & lacking the crisp treble. Confusing, but it's how Amps are. The 4ch Trio-Kenwood KR-6340 from 1973 is a regular on speakers with the Sansui TR-707A tone stage really bringing the amp alive. On Speakers it is sensitive enough to need Bass adjusting a tiny amount to reduce the thick sounding upper bass on some TV shows, yet on others better balanced it needs it setting back to the optimal point. Tone Stages are Essential on Speakers, we'd not try an amp without Tone that claims to be better if is just a big cost cut feature removed & hype lies to say it sounds better with a muddy sound. The KR-6340 sounds really great on speakers as our version is, but on Headphones it's not a good listen as it's Too Trebly with not much Bass. This is because the KR-6340 is a very low NFB design with Passive Tone losing a further NFB stage. Perfect sound on Speakers as it's so open & effortless, not unlike a valve amp. The Akai AA-8500 that's being Ignored For Sale gets tried to, a few more alterations & it gets used for a few days too as it gives yet another different sound to compare. Sansui TR-707A from 1965 is another outstanding amp, on speakers it sounds great not unlike the KR-6340 if a bit retro if it'll stay like that to have a different amp sound. On headphones it's a great listen if it doesn't have the lower treble detail of other amps, it sounds retro but suits speakers a lot better. But there is another option, the Valve Amp itself. The Luxman LX33 valve amp from 1979, our design inside though. What does it sound like? On headphones it get a lot of use on playing vinyl, the high detail of it can sometimes be a bit overpowering so to play it with earplugs just to have the music, if other times when in the mood that detail is as good as you'll get from vinyl. Odd one that to use earplugs to play an amp, it loses the treble detail if the bass is fuller, maybe the LX33 needs a redesign? LX33 on speakers to get this blog done reveals it sounds as different to the KR-6340 as is sounds similar. The midrange 'voice' is more upfront, the Bass despite the accepted idea of Valve Bass isn't as open as the KR-6340 & high treble is clean & open but not as upfront as some transistor amps. Conclusion is all these amps are upgraded by us but still sound different on Loudspeakers & Headphones. Which one you choose is what suits your taste, to swap around amps and use them in rotation has you realise what one has that's special & what one lacks that may be altered. The reality is the KR-6340 sound can't yet be put in the CA-1000. The TR-707A got put in the KR-6340 with the Tone design if otherwise the best way to swap & compare preamp stages is to use the Pre Out-Main In stages.


Where Does A Valve Amp Fit In With Varied Transistor Designs?

From the above blog, onto the 1979 Luxman LX33 which is all our design where it matters, theirs was lousy as said elsewhere on the site. Going from the Passive Tone-Low NFB design of the 1973 Trio-Kenwood KR-6340 again with modifications to the Tone design, it sounds rather like the LX33, if it os more on the extremes, Treble on the KR-6340 is upfront & bass is deep & expressive. But the LX33 initially is more restrained, but use if for 2 hours to get used to it on Speakers. The Deep Bass & Loud Treble is very different on the LX if it doesn't lack either, it plays it differently. With the Tube Technology 100w monoblocks & our custom valve preamp, it always sounded subtle until you got into the sound. It kept us pleased for over 10 years daily use no less so it must have sounded right. Here the LX33 after tuning in your ears to the sound is far more natural, treble is far from being upfront as can be got from low NFB transistor amps, but now it sounds right & is perhaps a more easy sound to hear as it just plays the music through 2x Tone-Pre Valves, Power Amp Driver & splitter then the El34 outputs. Transistor amps add more stages & the more Transistors there are, the 'harder' the music sounds. This recaps on previous opinions, if beyond using a rebuilt Rogers HG88 III we've not used valves on speakers for a while. That last HG88 III sounded great on speakers, it does use more circuitry than the LX33 but it does sound great rebuilt properly. The next "Amp Flavour" can only be the very precise but high NFB design of the Yamaha CA-1000. Playing it after getting used to Valve Sound to be used to the less upfront amp sound, how will it fare? It has some of the Valve Amp Sound, smooth balanced output with wider Stereo than the LX33. But the high NFB does upset the sound on being familiar with the KR-6340 & LX33. The NFB does flatten the sound too much, it's just too obvious to us if it does take a trained ear to hear this. Treble is clean & crisp but it can be heard flattened off leaving Sibilant sounds more pronounced at they sound a little clipped, if the're squashed by the NFB compression. The "airy" sound on a Stereo Soundtrack now sounds like an Over-Dolbyed Casette to those who suffered the cassette era & realised Dolby was more bad than good as it gained then compressed Treble to 'hide' tape hiss. We played with Dolby in the early 1990s on the 4ch Marantz 4230 receiver and found the effect was interesting if it did lose music detail too readily, just like overdone NFB can. Big Hifi Mag fuss about Dolby being 'essential' at one time around 1973-74 on Cassette Reviews, but they were being fooled really, Dolby on Tape is not good when played on big speakers, not the tiny BBC LS 3/5a that many unwisey used as monitors that are missing so much of the detail. You can hear CDs restored on tiny speakers as they overdo the "restoring" leaving dead compressed sounding mess that is unmusical. Back to the CA-1000 the high NFB especially in the Filter Amp has the amp sound "perfect" on headphones as the sound flattened, but 15" Speakers need the detail the NFB loses. NFB in preamps is good to a point, if overused it's too flat. The Sansui TR-707A is an oddball amp, it uses gentle NFB on the preamp stages if uses a very high value on the Output Stages. This is what creates the Unique Retro sound, on speakers it sounds great, on headphones it's more Retro as it has a Dolby-styled lack of mid-upper treble that makes it sound like a 1950s Jukebox gone Hifi, with big Bass, extended high Treble, wide Stereo if the sound on speakers plays treble differently. But this is Upgraded Amps, generally an amp will sound similar on Headphones & Loudspeakers. Big 15" Tannoys will make nearly any amp sound good probably as much as cheap small speakers can make the Best amp sound nothing special.


Marantz 2385: What Does This Sound Like After Comparing Those?
The 2385, 4 owners in 6 months before us as the sound on an aged raw amp like this isn't good. Our deep Service, recap with upgrades over the year we've had it now. It gets played still if newer arrived or redone amps get played more currently. It's a big 26kg amp to move around, it sits safely under a table up on end. It's a 1976 amp, amps of this era are very different sounding to the 1965-73 era ones. It plays great on our 1968 Tannoy Golds, if maybe asa original they suit the Tannoy HPDs better, actually they do as customers of our amps like the Yamaha CR-1000 & CR-2020 have the HPDs & they certainly impress them, but we've only heard a huge Pioneer SX-1250 on Tannoy HPDs in about 2003, the Pioneer was like a coffin on the floor & sounded as aged as the 2385 did when it arrived. First try of the 2385 today has it sound fresher than the CA-1000, treble is crisper if ours is upgraded to sound crisper than the stock version. Again it has the sense of what NFB can do with compressing the airy treble sound, if in fact the 2385 has very low NFB on the preamp. It just lacks the ultimate fresh open treble a few 1965-73 amps can do with the 1968 Tannoys, the trouble is once you know that sound, little else will impress. Our Marantz 2385 is a great amp, in terms of no hiss or hum, no mechanical noise, not wary of relay tripping as it clicks two relays on realiably & quietly. No slight 'thump' as heard on some relays on turn on even after making the turn-on delay slower on those amps. A Trusted Amp. It's a pity the Sansui AU-G90X didn't match the Tannoys, but there are a few amps that don't and that is still a mystery to solve. Based on all the amps we know, the Marantz 2385 is still the best sounding of the Post 1975 range of amplifiers made in the Tannoy HPD era.


Vintage Hi-Fi Sold As Serviced: It Generally Isn't Done Properly.
See the two Rogers Valve blogs above for the problem. People think that a few replaced capacitors soldered in 10 years ago is Serviced. Note the Rogers amps were still with 'Full Patina', ie Dirt collected still there untouched, nothing cleaned, nothing examined, nothing taken apart. A further idea of Servicing is squirting contact cleaner. This doesn't last long & it's baxk to being Noisy again as it's not servived. See our Solds Gallery Photos, we showed when we sold on ebay with "Serviced" exacty what the amp looked like. We took it apart, we cleaned it, we examined the track & connections for issues, sometimes tidied bad Mains connections that seemed unsafe. The sort of stuff your PAT test doesn't see. To do a Proper Service on an amp including many hours running in & testing is still quite a job. but the idea of How To Service to give a good product is overlooked as it can take 4-5 hours plus hours running in. Vintage Hifi, as with Vintage Cars, have no Standards, look on ebay to see that Sellers don't do our inside pics, if they copy the half pics & show sides & underneath, if the amp covers still screwed on. For us Upgrading & Recapping Amps, we don't really want Servicing Jobs as it's Money Wasted for the Customer. Early on, we took the amp apart to Properly Service it, being aware of all visual aspects, put it back together & then to Recap-Upgrade, it had to come apart again. Why not just Service & Recap in one, beyond a Quick Service to get a long asleep amp like a current 1973 National Panasonic SA-6400X needed. It was made good enough to use, but we've not had it apart fully until we get the Service Manual to see what to do to it. So Sadly... Serviced in a Vintage Amplifier doesn't mean much today as a 10 minute job blowing dust out & spreaying contacts does little. Regardless of what is claimed to be done, You Want photos & after years of us doing our detailed pics, very few do this even when they are asking a premium on Servivced & Recapped. You see those offering £99 service & repair, you take your risks on a cheap job as with anything. Would you ever get it back again? Only if there are Inside Photos can you see what the amp is like, if they say 'Serviced' but offer no inside photos, consider it as you wish at the price. May still be a great amp, but what they've done is still unknown. We put several "unboxing" blogs & used to write of optimistic dead spiders in amps, but these were raw untested amps often.


Want To Redesign An Amplifier Stage You Don't Like?

Continuing from the Aug 2019 "Butchering" blog, a stage can possibly be redesigned to be what you want it to be. It takes ages, it's done by knowing good circuits rather than the 'theory' way of working out values knowing voltages & currents used, as that's just sticking to safe circuits which isn't what upgrading is about. Upgrades bring the designs along but still test correctly & reliably in all ways plus more importantly sound better. It's far from easy if we've done a few this year: the 1972 Sony TA-1140 to lose an awful preamp design & the 1970 Akai AA-8500 to lose severe NFB in the preamp. Now we're doing the 1973 Yamaha CA-1000, the design at least makes sense, the later CA-1000ii is very different & the CA-1010 appears way overdesigned with three differentials on the Tone stage. CA-1010 was a dry sounding amp that at the time we couldn't do too much with. Yamaha has never sounded like that with low NFB as they always use more NFB. Resdesigning risks all problems of hum, instability, volume inbalance, hidden RF etc that can trash transistors. Redesign is very advanced if when components are put into the right combination to give a very different sound, it looks deceptively simple once the board is completed, as does any output from a complex recipe. It then takes tech testing to see it's correct & adjust if needed. Then long listening to see if it's the sound you actually want. To keep good notes on what you done, as even weeks later what you did can seem a mystery. The CA-1000 we got good results to a degree with if the overdesigned CA-1010 is one that can't be dealt with as too much 'rubbish circuitry'.


September 2019 Blog

1978 HFN/RR Article About "Irresponsible Hifi Reviewing" By A Hypocrite?

The 1976-78 era in the Hifi News/RR magazine is really shaking up the Old Grey Men. Some may be Hifi Legends like Peter Walker of "Quad" with his heavily tailored amps to suit his 1957 Electrostatic that has smooth midrange yet no Bass or real volume. A supposed "test" of his oafish "straight wire" idea of a string of Quad amplifiers sounding no different after multiple amplifiers in-out-volume reduced-in etc is ridiculous if this 'battle' never fully occured & a weak excuse why is all we got, saying that "nobody knows" as the results were 50:50. Thankfully some Young Hippies took over quite a bit in 1977, Paul Messenger soon departed to 'Hifi Choice' books & bored many with the Linn-Naim-Meridian ideas that are as basic as can be yet "better", not many like these brands & wonder why so many 160/250 amps are for sale, they sound boring is why. Martin Colloms was more in-depth if continued to be almost unreadable with pointless 7, 5 & 6 amplifier tests over 1977-78 that hardly told the potential buyer anything, to understand what he means but it's over the head of the typical mag reader as letters pages told. The tedious opinion this time is May 1978 with Gordon J King. We've read all his reviews since he started at least ten years earlier. He is a very tame guileless reviewer, he spends most of his time condensing the User Manual & describing looks than testing & until 'forced to' on later years if made no effort to describe what the Hifi Sounded like. People buy Hifi Blindly & often get sick of the sound to go Blind Buy more. Here GJK tries to justify with a page and a half of Waffle, blaming the input transistor gear as being poor sources without explaining why. We've tried enough UK-EU gear & wish it was better in the 1965-80 era, but it's not. To get the Hifi News set to read the reviews, they get some of the good ones to review, if not all. Their 1973 Yamaha CA-1000 review only says how good it is yet to tell the reader why they should buy it when new is never really told. Those confused Colloms multi-amp tests (as we wrote of on our Books page) shows that these amps don't really sound very good despite the 'impressive' pointless Specs. We write of how Amps Sound, much after Recapping & Upgrading. We do Tech Tests on all amps to see the Sine Wave Output & some get tested further with Rise Time. We care not about THD as you can't hear it if "raw" amps can sound rough especially UK-EU ones. A Distortion Meter we carry with us everywhere, the trained ear picks up Distortion & Untidy Sound that Meters can't do. The Ultimate Test is to use the amp to listen to it on Speakers or Headphones & do this for days or weeks. Hifi is for Listening To, all the Tech Tests won't explain why an amp sounds good or bad, but Knowing Design looking at Circuits we can often tell how the amp will sound. Only the overdesigned circuits can't be predicted, except for the fact overdesigned doesn't sound so good. So Gordon J King Reviews 3 Receivers. Same issue, May 1978. This is what he considers 'Good Reviewing' so we'll have a look. Rotel RX 603, Yamaha CR-620 & Trio-Kenwood KR-4070. We've had the Rotel, know the Yamaha CR-820 if not tried later Trio for risk of ICs. To say these would have sold well at the time & are considered Quality Brands. The Reviews naturally cover FM performance, not many FM stages on Receivers are that great, muddy dull sound is what we usually hear, UK's Radio 2 the only uncompressed FM station tells how good a Tuner is easily. Amp stages get Power Capacity, Amplifier Distortion & Frequency Response. Not too promising is it, Watts is easy, Distortion as THD is meaningless & Frequency Response is useful for good Square Waves revealing Slew Rate & Rise time, not that HFN/RR tell you these factors by now as it tells Too Much about Amplifier Design & Sound. Rotel RX603 we thought sounded basically good if sounded rough played louder from cost-cutting, we've heard much more impressive 45w amps than this. GJK's review is frustrating, he just spends half the review describing what your eyes see & what the user manual says. Then FM stages info that few will know what it's about. Onto the Amp stage, he tells it plays 50w+50w with ease if it picks up bad power supply hum pushed hard, bit silly as in normal use it's fine, who gets a 45w amp & pushes it to full power? He says reviewers overlook this, can't imagine why, the amp is at the top of it's power range, it complains as does every amp. The full power 1kHz test brings up harmonics, because it's complaining, yet a graph is needed to show -55dB harmonics that you'd never heard at full power. He didn't like the Treble Tone saying it should be tamed, this is what gives the amp a generally pleasing sound & should Square Wave test well. We had the RX-1603 more recently, similar cost-cutting if still a better amp for the era. But the Sin here is Zero Opinion on using it, the garish lights, the silly handles, the lack of confidence in the Sound is all bypassed. The reader of this would have no idea if it Sounded Good or not. Our Opinion of the 603 as original would be it was a good buy at £225 for a 45w receiver, if not to expect too much from it in terms of Finesse. Yamaha CR-620. We liked Yamaha 1973-78 amps & receivers, for us liking them the Brand has been revived when in 2011 they were just 'secondhand amps', nobody told they were good amps. We had the CR-820 & found the build quality disappointing after the CR-800, too many cramped up medium power transistors that got hot, all on one main board, see our Sold Gallery pics, it's a bit messy if still looks good externally with the wood veneer lids on. We've not bought any more of the CR-x20 range beyond the CR-1020 & CR-2020 since, if have got all the CR-x00 range except a CR-600 if would try it. Our brief 2013 CR-820 review says we liked the sound on the amp, so the CR-620 will be a decent amp. 40w for £230 is again good value, if you see where costs are cut. GJK says it gets rough sounding at 16kHz played very loud at almost full volume. Again a pointless test to say on what is a good Midprice Receiver. Beyond Tuner & the lazy describing as with the Rotel, nothing is said about the amp. As with the Rotel, it should be said they sound a lot better than some competition & both are Recommended Buys at the price, but none of that by GJK. We know these two amps enough to say they are worthwhile. Thirdly the Trio-Kenwood KR-4070. We don't know this amp & are wary of ICs, so to look at the Service Manual. This is a 40w receiver of rather plain looks & £188 means it's cheaper than the others by quite a margin bearing in mind 1978 values. Manual shows the later one-board & heatsink inside idea like 1980s amps use. The Circuit is a bit dismal, ICs for Phono typical of the era, but as with the 1985 Dual CV1470 it has Tone Stage further into the Power amp. This compromised design is not so good we found with the Dual, if we have seen this in other amps of the 1978-80 era. Aux to Volume & Balance & onto the Power Amp differential with no preamp stage. Tone is before the Push-Pull drivers as Passive design in the NFB Loop, if put so late in the Amp it just seems a bad idea. An amp like this would need to be heard to hear if odd ideas are any good, too hard to guess on this one. JK has the thing so we look to him for guidance. But there is none, his 'Lab Tests' are utterly pointless & the 1978 reader would not know of the different design as we found looking at the circuit. Conclusion. The Gordon J King reviews in this issue & before are generally Worthless to any reader. They would have No Idea if these are Good Amps or Rough Sounding to be avoided. No opinion on Sound beyond they mostly put out the same volume which with 40w to 50w is no surprise. The Reader would decide on Cost plus Which The Wife liked, the Yamaha with Wood Casing is more Home Friendly. The Trio looks Budget styled, the Rotel looks tacky with poor fascia lights & silly handles. You'd do good buying the Yamaha based on looks alone, but Gordon J King is a Terrible Reviewer. He is of his mannered & dry Tech generation, born in the 1920s & nearly 60 we assume. Reading The Long Hair Hippies like Martin Colloms & Paul Messenger is what livens this era up, silly stuff about Jean Hiraga ideas on cables & turntable mats is mocked if the ideas continue today as truth is in there, plus know-alls like Quad with their Big Amp Test fizzles away as they only get 50:50 "we don't know" responses as stated alredy. You really are given No Idea in Reviews beyond MC & PM what the amp sounds like & the MC ones use too many people to gve an overall opinion. You Buy an Amplifier or Receiver to Listen to, your only Hope were Shop Demos assuming the Staff weren't just trying to flog dead stock. As with this site, we just Bought Loads Of Amps to test them to our needs. Our needs meant we've revisited many amps since 2011-13 to look deeper. Not many Hifi Buyers have more than One Amplifier, the one they use. To swap amps around on speakers really does show how different they sound, even ones much upgraded will always sound different. See a Blog later in this Month for an Update on GJK.


Passive Tone Stages In Amplifiers.
This is an early type of design first seen in Transistor Amps that were The Next Amp after The Last Valve Amps. It's the alternative design to the Rogers HG88 III that has the Classic Baxandall NFB Valve circuit which sounds very good on this amp. Passive Tone has a Ground Reference is how you spot it, together with no link from the transistor before the tone to the one after, as in NFB. It's an interesting design to know of. An amp like the 1970 Akai AA-8500 uses NFB around one transistor, this isn't Passive therefore & this NFB design is mostly used. Many valve amps used the Baxandall-NFB type such as the 1965 Rogers HG88 III, if some early ones used rather Primitive ones that aren't too successful. Either NFB or Passive can sound great, as with any amp Design it's how well designed it is. Past the 1967 ranges, the NFB Tone was generally standard, because it gives good results more easily as most are pretty similar or just copy the basic components design. Passive Tone in later Amps was considered only on a few amps: the Sony STR-6050 & STR-6850 that are midprice amps have Passive tone. We've put the TR-707A design into the 1967 Sansui 400 which really brought it out & the Trio-Kenwood KR-6340 being a 1973 4ch receiver has Passive Tone so to try the TR-707A design which gave great results, showing these passive Tone stages were not great designs. To Find More Passive Tone Stages interests just to see how they did it. There are probably a lot more but these will be Budget Amps not really in Hifi terms, if the 15w Marantz 1030 is Hifi. So we have 1965 Sansui TR-707A, 1965 Sony TA-1120, 1966 Akai AA-5000(S), 1966 Akai AA-7000, 1966 Rotel 100AMP, 1966 Sansui 3000, 1967 National Panasonic SA-65, 1967 Rotel RA-110, 1967 Sansui 400, 1967 Sansui AU-777, 1967 Toshiba SA-15Y, 1968 Sansui 3000A, 1968 Sony STR-6040, 1968 Sony STR-6060FW, 1969 Sony STR-6050, 1970 Hacker GAR 500 range, 1970 Rotel RA-610, 1970 Sony STR-6850, 1971 Marantz 1030, 1972 Rotel RX-800, 1971 Sony STR-6055*. 1985 Sony TA-F550ES is a late one. Notes: Sansui NFB Tone by 1969, Rotel NFB Tone by 1971. 1967 Sony TA-1120A may be passive but very hard to trace through many controls without it here. *1971 Sony STR-6055 has the Passive design if uses NFB also, odd one. Passive or NFB Tone is as good as each other, much as Capacitor Coupled or Differential Direct Coupled Amps are basically no better than each other.


Filter Stages Are The Worst Designed Parts Of Too Many Amplifiers.
Nearly Every Amplifier since the Dawn of the Era in what we consider Hifi Amplifiers, as in starting with 1963 designs, has had Filters. The 1963 Trio WX-400U plus the Fisher X-100-B type of Valve Amplifiers with Power Supply Diodes instead of Valve Rectifiers are the earliest we can properly upgrade to give Great Results. Amps with Valve Rectifiers are an Earlier Generation that we don't cover. Filters are Low Filter aka High Pass Filter confusingly. which reduces the deepest frequencies in an era of Rumbly Turntables etc. High Filter aka Low Pass Filter reduces the highest frequencies. High Filter was much used to Filter off Rough Treble which is often found in amplifiers if this we can upgrade to give Smooth Treble. HFN/RR magazine in the 1956-70 era had readers & reviewers who could only use their Hifi using a Filter which suggests their Cartridge, Phono Stage, Amplifier or Speakers wasn't as good as it can be, not everyone could afford & slavishly only Bought British who were being overtaken. Quad & other Brands offered many Filter options with sharp cut offs via using Inductors which gave the effect listeners wanted. The fact you lost a lot of the sound clearly wasn't so important & be sure many still use these Filters. But we have No Use for Filters, we've spent years upgrading to expand the amplifier Bandwidth & do it cleanly, not that all amps can give the same quality. The Most Ideal Filter Stage we've seen in any amplifier is the 1965 Sansui TR-707A one. Filters do not affect the sound or get in the signal path in any way. The Design is So Logical & Perfect yet we've never seen it in any other amp. The Filter isn't a steep filter with a sharp 16dB cut off to please the fussy filter user, but the Bass Filter simply puts it through a limiting capacitor & the Treble Filter works it into a NFB loop with the Filter using higher NFB in use & only slight NFB when not used. We've tried bypassing some Filter stages, such as in the Sony STR-6120 to hear how the Stages Affect the sound & in the case of the Sony, seemingly large resistors don't reduce the sound as Impedance affects the sound differently, as with Grid Resistors on Valve Amps may look limited but make no difference to Audible Sound. Onto The Bad Design. Unfortunately as with a lot of Design ideas, the bad idea of Over Complicating Things aka Overdesign gets some hideous Filter Stages. These are in late 1960s to early 1970s amps too, it's not just the post 1977 era. One Amplifier puts the Filters after the Volume so are actually Dangerous to use on a much upgraded amp, huge thumps in use would send the amp unstable & trash the Power Amp, this amp is the only amp we've removed the Filters from as it's a bad design if the amp as sold is tamed enough to not make issues. This amp had an update bulletin issued very early on where it must have thumped badly as sold on the very earliest ones, as the ones we've had are with the alteration. No names mentioned, as in which amp. The Yamaha amps with the Filter Amp aren't great if these can be much improved. Another Amplifier we've had was always rather 'fake' sounding. It sort of had the right sound, but it didn't please the Subconscious as the sound wasn't strictly authentic. Try as we may, the amp just wasn't convincing. After having worked out Filter Stage designs the dark Moment on Realising how Awful the Filter Stage was in this amp really upset the ideals, why are they selling amps with such bad design, this is from a big name if we had difficulties with similar ones of theirs before. The ghastly Filter Amp stage mangled the sound with severe limiting & just no way to get out of that. The design on further examining, the sort of extra complex circuit pdf with very long lines between boards so you don't realise what they've done revealed more Horrors that covered their cynical cheat up & caused noise the bad ideas made by 'tidying' them that few would ever realise. All helped get the 0.0x% THD, mangle the sound to lose all the problems. This shocker isn't unique, reasons why so many amps past 1977 just don't sound nice is because of similar bad circuits & sort of back tracks to the Musicality that was the Buzz Word in Hi-fi 1977-78. 1977-78 Yamaha still sounded nice which is why we got so many of them & revived interest in them. But in that era, no-one understood about Cost Cutting, Low Spec, Current Limiting & generally manufacturers selling you craftily worded hype if selling an Ideal that was never really there. No Reviewer was examining Circuits to see What Rubbish, Compromises & Sound Shaping were being sold to The Public. All we see online about Poor Design is when Monster Receiver Power Supplies go wrong & then what they do to 'better' the issues aren't ideas we'd choose.


The Trouble With Hifi Designers... No Retrospective Knowledge

The idea was always to Forget The Past & Design a Great New Idea that itself would be Forgotten by the next Model Range usually 2 years later. Perhaps We are the Only Ones to know so many Hifi Designs over years of Recapping & then With Upgrades. A designer in 1976-77 was far more interested in getting Worthless 0.01% THD than caring how good it sounded. The "Musicality" reaction in the Hifi mags showed people weren't happy with these 'New Improved' Designs. The Further we Look into Hifi Designs, the more we understand & can see where Faults are, the Loudspeakers page lists All Amps we tried on our Tannoy Golds to see how they matched. Plenty rated "Great Match" yet the ones past 1971 didn't seem to match quite as well if still got a "Good Match". We have taken certain amps & upgraded to get "Great Match", just for the trying of ideas & this shows Speaker Matching isn't in the Power Amp stage usually, it's in the Preamp. Looking at our Solds Gallery, a remarkable array of Amplifiers from Great to Good To Awful, to remember Amps that sounded poor on Speakers yet were Great on Headphones. We play Headphones Flat on the Tone Controls, but on Speakers we need Tone Gain, Tannoy Golds are Neutral Sounding if it seems Tannoy HPDs match better to later Amps from what others tell us. Knowing Preamp Design better than any Mid 1970s Designer who doesn't realise the Great Amps of the Earlier years, such as those 1965-73 we can see "You Designed It Wrong" on quite a few amps. The 1971 Yamaha CR-700 we initially liked but it sounded awful on speakers. The 1984 Sansui AU-G90X we done so much with but could never get it to sound good on speakers if the buyer of it has later speakers & it sounds great they say. From Recent Amplifier Experimenting based on a 1965 Amplifier, we now see exactly why those amps didn't match & can see what needs redesigning for them to sound right. The 1970 Akai AA-8500 we rated "Good Match" yet for changes it's on our Tannoys as of typing as it's now a Great Match. To see certain amps that we liked but didn't quite do it on speakers brings grumbles, but these amps were a few years ago & possible to get them again if priced sensibly. For an example, that 1965 amp is the Sansui TR-707A. It has Filter Stages that many amps make a total mess of severely limiting the sound in extreme cases. The Sansui uses very simple stages, maybe not as Steep Filters as was wanted, the Quad heavy filter stages were much used, to cover up how rough treble was usually. If you understand Design, go check out their Filter designs, if this we've never seen fully in later designs. In comparison the 1966 Sansui 500A valve receiver was clearly designed badly with really awful Filters & Tone stages, lousy weak design as we noticed on having that amp, did lots to it but it was with too many problems so we got rid & were glad to. Recently the Revox & Grundig amps similarly we really didn't like so just got rid of rather than suffer their poor design. Our Upgrading is based on knowing design that makes a Great Amp & to put the Best Ideas within reason into Upgraded Amps to give Great Value in Customer's Upgrades without going into Maxed Out Upgrades costing too much. This sort of Awareness of Good Designs seems to be in the Car Upgrade scene, but that's been going since the 1950s. Amplifier Upgrading is what many try as "mods" on Forums, usually awful ideas unaware of the amp needing upgrades all over to bring out the best.


The Yamaha CA-1010 Amplifier.
On the face of it, this should be The Best 1970s Amplifier. It has 100w power, it's got big meters, Class A, sensible fascia controls, wisely a High Filter only and No Loudness. We got one as we reviewed in 2012, at that time we'd just recapped the Yamaha CA-1000 to find it nice but a bit dull sounding. The brighter & thinner CA-1010 sound as original was more impressive & the CA-1000 we sold on a bit too fast. The CA-1010 stayed a while, it was found clean sounding but Bass was thin & the balance was bright on headphones if this was before we tried Transistor Amps on our Tannoys, we tried upgrades if now we may do more. The Sept 1978 HFN/RR rear page ad says "The Yamaha CA1010 certainly won't be your first amplifier. It could well be your last". A little sinister perhaps, is one of the buttons wired to Mains? No, it's Yamaha's quaint headlines like earlier ads pre the CA-1000 range naively said "Anyone could have done this, Yamaha have" or similar. Yamaha use the "Natural Sound" NS Series going back to their 1969 Music Centre. We liked Yamaha to try enough models & revive the Brand to Vintage Buyers, prices varied if now are Overpriced for Raw Amps sadly, they'll see they're not selling & price more realistically, we hope. The CA-1010 has it all, but the sound isn't right & as with the CR-1000 we found it too upfront & harsh, the 2012 first review of the CA-1010 said this, copied unedited from an old page not online... "Disappointing Amp. This on paper apparently looks like the best Amplifier (ie not receiver) that Yamaha ever made. But after much effort trying to better it, the opinion is it is hard & cold sounding, bass is left wanting & it just sounds rough from too much overdesign in all areas. It is loud & impressive so would appeal to those thinking later 1970s Pioneer are Hifi, ouch. You can upspec it a lot, the thin bass can be dealt with depending on how far you want to go & the sound is easily one of the biggest powerful soundstage delights we've heard or got from Solid State! Others may be sweeter, more detailed & more natural, but the CA-1010 will kick like few others. But it'll never be the best Amplifier as it is too overdesigned. Other amps don't have the volume & effortless power. Big heavy amp well made if still a captive mains cable & odd screw fixings for bare wires only, certainly better than small hole spring connectors. Gets very hot in Class A. This amp uses Push-pull Tone & Phono stages and the sound isn't anything as natural. It offers Class A by using the Class AB pairs but biasing them as always on, they create a lot of heat as so inefficient but add a fineness to the Sound, but in the case of the CA-1010 the sound is so mangled by overdesign, it didn't really make any difference, the fact the Phono & Tone are Push Pull (Class B) & then the Power Amp being Class AB or Class A is mocking the buyer just a little. That's what we wrote in 2012. Yamaha Power Amps sound good on the 1973-78 ranges, but the Preamps on the higher models get like many amps do by 1976-78, they just get overdesigned. Filter Stages with terrible design, excessive Differentials, excessive Transistor stages, needless NFB are what put the post 1973 era at an Audio Disadvantage.


Listening Tests, Subjective Opinion Then Backing Up With Tech Testing.

Reading the Nov 1978 HFN/RR about Reviews, Subjective & Objective testing, one of their more grounded writers, Adrian Hope who later wrote under his real name in the 1980s HFN/RR as 'Barry Fox' has a look at all the fuss about Reviews with Objective not being liked by writers as far back as 1935 saying that people give far too much credibilty to a technical test that tells nothing of how the amp sounds. Considering Valves & Electrical Recording of Records only started in 1925 this is great to see that Percy Wilson took issue with this. Many will say "This Amp Sounds Excellent" but have very little experience of 200+ different amplifiers to listen to. What they say is "Excellent" we may think is OK but way short with very obvious aging & weaknesses. Then even fewer will be able to Upgrade & Better Amplifiers that are of dumbed down or inadequate design. Play any Amplifier Briefly & your ears will tune into the sound giving a Head EQ to tame bright Treble or fill in lacking Bass. This makes the Group Tests of Amplifiers interesting but never conclusive which sounds "Best" as all amp designs differ. Level of Tone Control you require & what the Amplifier provides we've found can affect "Matching" as being able to redesign the 1970 Akai AA-8500 to go from "Good Match" to "Great Match" interestingly takes away all the worries of an amp matching or not, because it can be altered, if not on all amplifiers. Then, as we find with the AA-8500, an amp we've not 'Maxed Out' the Power Amp if have altered it quite a bit, it sounds a little strange, improves further though, it has a great Soundstage, Bass on TV shows really kicks out, if it still lacks what more upgrading can do. How do you Tech Test that. Impossible to, this is Strictly Subjective by a Trained Ear. Said AA-8500 has been on the speakers for TV sound over a week now, further changes as deeper listening reveals really bring it alive, if before it was clean but Dull Sounding & we couldn't work out why as it was very clean on Headphones. This amp is still a work in progress, if seeing how cool it looks in it's light wood case, good job it didn't sell, because it has no real cred yet beyond us. As original it's not great as far too tamed. But to mention a real success, one lucky customer got this as we had Three 1960s Sansuis & to thin them out. The 1967 Sansui 400 has been blogged before. Old amp with some crude design we redid, just to see how it could be. It upgraded well, sound improved every time, if on Tech Testing with an oscilloscope to see the Max Clean Sinewave as we show on the 'Power Ratings' page. Here the 400 showed up it was way off, the Sinewave clipped off on the upper half. Knowing Amps & Circuits to know what causes this, experimenting how to solve this with some redesign later & the Sinewave is correct to Clip Evenly at Full Power as it should. Redoing the Amp altered things, the Sinewave test on the Speaker Outputs showed this up & tracing where it started helped get it altered. Extreme things to do with upgrading is why most won't try as it needs Fault Finding & Problem Solving, but why not learn how to solve it. Listening Tests for Subjective Opinion is very important, if we by Upgrading improve things hugely sometimes & these test great by how Great They Sound. We've done Blogs testing amplifiers with how they perform including Rise Time that shows how fast an amp can be & interestingly in the brief time Rise Time & Slew Rate was mentioned in Reviews, our readings would scare the 1976 reviewers. "Too Fast" they'd say, but it's about Quality that has Design Support to Allow such Fast readings. The AA-8500 Power Amp we can hear where it lacks what other upgraded amps can do & this is what can be upgraded further. These Improvements we can do, but the Reality is it takes Ages to work out what an amp needs & where to go further which adds up in Cost that could Way Outprice an Amplifier. Tech Testing is certainly worthwhile to Sell An Amp when it was New, confuse the Buyer with Meaningless THD 0.01% ratings that make no difference. Tech Testing to us is GIve A Stable Amp, Clean Sinewaves clipping evenly as possible. Lowest Hiss & Hum plus No Annoying Switch or Relay Noises which sometimes isn't possible. You Hear on "Top Gear" that it's a 'Driver's Car', similarly the Best Sounding Amps are 'Listeners Amps'. We'd never consider Quad, Linn, Naim, Meridan, or other boring black plain box "Hifi" that still sells at £1000 despite very obscure brands, to be 'Listeners Amps" as they offer no User Controls or Likeable Sound despit testing so well when stuffed with ICs & a Sheep-Like Brand Loyalty to 'Upgrade' by buying an add-on unit. You'd have more Musical Pleasure buying a 1971 Leak Delta 70 amplifier.


Comparing Amplifiers By Longer Term Listening.
As Blogged above, the old Multi Amp tests don't really work with Upgraded Amps as similar Ideas are in them. It did help learn the Differences in Sound to then Pick Out Amps worth upgrading further. Now we use the Amps on Speakers for a few days or longer to learn how they sound. If we like the sound, to keep with it longer as it pleases. Take two receivers, 1970 Akai AA-8500 & 1973 Trio-Kenwood KR-6340 4ch amp used as 2ch Bridged. The Akai we've not really used much on Speakers as it didn't match as good, if it's a Real Classy looking amp. On testing it this month, it has many good qualities if to feel it's still lacking. The Power Amp has been improved if not fully. So to go back to the Trio & the sound of that really is spot on, can't criticise it or want more from it in terms of sound. It sat ignored unselling for 6 months until we decided to upgrade it a lot more as it sounded so nice on treble & mid if Bass was weak. Akai to Trio tells the Trio has a similar open soundstage in the 'effortless' range which isn't often heard with amps. But Akai doesn't quite have enough Bite to the Sound on retrying, a lateralteration made that amp sound much better, the Trio's Treble & Bass go further plus the sound fills the room better at lower volume, to give a very smooth yet lively sound, the Akai could do with a bit more which subtle changes do bring. But this takes days of using an amp hinking what it lacks. These last two blogs are a bit thinkng out loud if it shows how we go about upgrading & wanting a sound into an amplifier. Of course, use another amp for a few days to then try the other ones, they still all sound different. Sometimes one amp suits you & then another time another does. We currently keep 3 on rotation including the 1965 Sansui TR-707A. They all please when used & all sound rather different to the point of a bit confusing if using one amp for an hour then swapping to the other. The Fun of Hifi.


May 1978 Brings IHF Technical Standards To USA Hi-Fi.

This alone is why Hifi past 1978 gets difficult, compared to the Joys of Transistor Amps 1965-77. IHF is a USA standard designed to brig what is called Hi-Fi into following certain standards. it's a much stricter set o rules compred to the previous 1966 version & the 1966 DIN 45 500 German Standard. What the Criteria is was never published in HFN/RR if a Dec 1978 article mentions it without saying anything. The only info that tells is -80dB Noise Floor is considered the standard, Hiss & Hum 80dB below the 0dB maximum output. The full specs can be found online now to see what changed. The Trouble Was that All Manufacturers had to Conform to be able to say they are using IHF standards & their date in manuals to quote Power Ratings, THD etc, if they didn't the idea was they'd not be trusted as seemingly sub-IHF-standard. The Outcome of this is Manufacturers had to Tame Amplifiers to get this -80dB Noise Floor. Try Google search for "IHF 1978 hifi" & you find we looked at this Here on Jan 2018 blogs as we last read through the HFN mags. A further Blog less annoyed than the previous IHF one Here tells more. These Blogs are written showing what we think of things as they appeared during the 1956-80 era & ones like this IHF are annoying as you can see as they killed off the chance to get Great Subjective Sound, probably much as "CE" badges in later years restricted Hifi even further. To force Specs onto Hifi makes Manufacturers Tame Down Hifi even further, That 2007 Marantz PM 6002 you'd think would have Better Low Noise Transistors, but after removing 100+ pieces of Dumbing Down, the Amp was as Hissy as a budget grade 1970s amp. There is No Progress in Hifi, the technology beyond Digital & Limited IC Spec is all that grows. Hifi past 1978 gets Too Samey, they all copy the same Pioneer SX-950 type fascia, by 1980 Power Amp ICs arrive, by 1982 medium power smaller items are all there is after the 1976-79 Monster receiver era. In cars you hear of the Muscle Car era being ended by heavy restrictions on Engine Power in a fairly similar way. Back to Noise Floors, aka S:N ratio, in older amps the Background Hiss & Hum can be noticeable. the 1965 Sony TA-1120 is very designed to give perfect Square Waves plus a -110dB noise floor which is very impressive if the NFB on the amp is a bit high to limit the expressive sound to get this reading. The 1967 era of amplifiers are far better on S:N (signal to noise) levels, the 1967 National-Panasonic SA-65 quotes -70dB whih after hearing one recently is a modest rating. The 1967 JVC 5040U rates -80dB which is very impressive. These use an amount of NFB to get the low noise ratings, if still sound great. 1966 Sansui 3000, pre the 'A' version is -75dB which is again very decent. The 1965 Sansui TR-707A rates at -70dB if to question that for noisy Germaniums & how the Resistors age too, but we hear it 54 years later & it can get back to -70dB with a lot updated, ie new resistors underneath. To Force 1978 IHF Standards onto already Heavily Cost Cut Amplifiers sadly is a Nail in The Coffin that ends the earlier Good Sounding era. A great 1984 amp the Sansui AU-G90X still needs a huge amount to improve how tamed it was.


The Darker Side Of Working On Hi-Fi...
Some may think it's easy to just put new parts in for old, plug it in & done. Some even think to Just put New Capacitors in & it'll solve all issues, which is Wrong as the design in resistors, transistors & capacitors will be the same. But the Reality of "Solder It-Done" is far from that on nearly every amplifier we've worked on. Many do work right first try as you'd hope a Pro Hifi tech would be able to do, but often you are 'running in concrete' for the obstacles these amps put in your path. Wires coming loose is regular, wires not long enough brings strain. Boards can't always be removed as there are far too many connections to unsolder so you're left moving the amp up & down to find the place where a component is to find the solder track for it. Then the mess of design leaving even that awkward with other parts in the way, as in messy designs. Illogical Problems can really test the patience, a sort of thinkng "they did this so you'd get annoyed, break it & go buy new" is actually pretty true with modern gear. One channel can go quiet, it tests fine mostly but no sound & the Board is really hard to get to, it's a "Loosie". If amps get annoying, as with that 1967 Pioneer SX-1000TDF, put it out of sight for another day. Next time you look generally you'll find the fault. The Negativity of working on Amps that "won't behave" is a real downer & to need to put them away similarly. More Success with Amps thankfully is what keeps it Good & this helps balance the stinkers. Getting Negative results only for a day or two is bad to get, so to try on ones that will not annoy balances things. Negativity with Hifi gets you Questioning your Whole Hifi Experience, it is possible to get such great results with some amps that it leaves others once considered Reference Amps now though of as "not very good" and needing a rebuld with new ideas. How lucky the person who is forever content with an amplifier never to consider it can be bettered. We used the Tube Technology valve amps for 12 years daily, doing upgrades but being happy with them. Today they don't get used, after 5 years of trying Transistor Amplifiers, the TT's don't sound so good. We've had 1960s Valve Amps recently, the Rogers HG88 III sounded exceptionally good on our Tannoys and we have another to rebuild even deeper to again compare to our Transistor Amps when it's done. But the 1979 Luxman LX33 & the 1993 TT amp & pre now show up as lesser. The LX33 isn't as smooth & refined as the HG88 III or other amps that now better it. The LX33 to be honest was a bad design as original, we spent three years getting it to sound better yet now it's surpassed. What to do? The Pursuit Of Perfection can often lead to finding out once-accepted standards are now bettered & you're left in Limbo. We have wondered several times if the LX33 Output Transformers are the issue, wound to match 1979-1993 era speakers, the 1960s Rogers & Fisher TXs sound so different. Hearing that HG88 III it really amazed how good it sounded, yet the LX33 on speakers was always lacking the smooth sound & nice Bass. The TT amps were never great on Bass if smooth on the rest. TT 100w Genesis Monoblocs were compared with the Sony TA-3200F 100w power amp, the Sony was hugely better, the TTs sounded soft & vague. The HG88 III, in comparison to the Rat's Nest some Valve Amps are, is so nicely laid out with no lousy design. Pity Rogers didn't do an EL34 version. Maybe that's what the LX33 needs, a HG88 III clone into it, after all it sounds so good. To turn Hifi Negativity into Hifi Positivity is what keeps us going. To find the LX33 now has been surpassed needs work done there. Keeps Us Busy. Blogs like this are us thinking out loud, typing the issue & seeing a Positive outcome.


Is It Possible To Put A 1966 Sound Into a 1970s Amplifier?

That's The Dream isn't it? Even to put into a Remote Control Amp. The latter may be possible if to choose the right amp with no ICs would be a tricky one. But to walk before running. The 1973 Yamaha CA-1000 amplifier on paper & looking at it appears to be one of the great amps. 70w power is enough for 95% of users. But it's design is holding it back. Yamaha power amps are very decent, but the CA-1000 has far too much gain, far too much NFB & why it needs a Filter Amp is a bit of a downer. It has cynical spoilers that hold the sound back. The joy of being able to redesign, in a breadboard way, can get the best sound. To get good results from the CA-1000 is nearly a year after after getting a frazzled amp from Class A heat without ventilation by the previous owner who kept it 40 years if it had far too many issues, not the sort of amp for a customer to get sorted, it'd cost a fortune to get it working. But it's our amp, time & money spent is Our Research to bring the Best Upgrades having worked them out. The 1965-66 sound is in the Sansui TR-707A, a real gem of a design if forgotten. That amps needs a huge rebuild, but again it's for us. The Yamaha needs some quite intense redesign which results in the hard loud sound gone to be replaced wth a "Bouncy Bass" that we first heard in the 1975 Luxman L100 if it was far too tamed otherwise. The CA-1000 sound now has very wide Stereo, deep soundstage that is effortless, clean treble & a lively bass. The Hifi mag reviews once they started telling of how Amps Sounded tell that the Yamaha CR-620 sound is good but on close listening it sounds muddled, as in blurry & lacking focus. This is where they upgrade well. Redesign needs voltages correct to not clip out, to be the right volume & not Hum, juggling all together is very difficult if can be done with much patience. The loud but not focussed sound is exactly how the CA-1000 sounded before. So the CA-1000 now sounds lke a tighter sounding TR-707A. What it sounds like on Loudspeakers is the next thing. The CR-800 receiver is very like the CA-1000 in some ways. The CA-1000 on speakers overall sounded good, but the match wasn't right as too much on the Midrange, meaning more to try. Wew could hardly do this for a Customer's Amp, but fascinating for us to try.


1970s Amplifiers Are Failing A Lot Now.
We get a lot of Messages about the better mid-late 1970s Receivers & Amplifiers by brands like Marantz & Pioneer. These are failing now as they are over 40 years old & over the last few years they are going from working to just giving up, no relay click on. This is because the components used aren't as good quality as say ones from 1972, because manufacturers had to cost cut. The Reality of these giving 40 years service is still Great compared to gear today that is disposable in 2-5 years. Your Smart Silver Faced Receiver or Amplifier is often Forever Repairable, so don't just let it sit abandoned & not working. Amps with complex ICs & Output IC Blocks, V-FETs etc can be difficult, ie mid 1970s Sony, Trio-Kenwood & Sansui as parts aren't available. Leaving an amp untouched until it fails is how most use an amp & when it fails it can cause damage. But based on many we've seen, they just need to be Properly Recapped & with The Unique Upgrades we offer when we Upgrade, your Amp will sound a lot better than before, improved full Bass instead of dry bass or the false Retro Bass, a cleaner Midrange & crisper tidier treble. All this does cost of course, but an investment now in your amp could get another 40 years use, a suggestion not a Guarantee. Quality Amps are Complex, expect at least a £600 job on these receivers we get asked about often, could be higher, will be lower on more simple amplifiers. If you don't want to spend the money, sell it on ebay, it won't make much as Faulty, but be sure another will revive it. Be sure any modern amp for £200 on Amazon to replace it will not please, today's IC junk is disposable. Your 1970s Beauty Deserves Reviving. Ask Us.


Fault Finding And Part Repairs Are A Waste Of Money On Pre 1980s Amps.

We See how Other Repair Techs operate, This "TV Repair" mentality annoys us, it wastes the Customer's Time & from invoices we see they charge almost what We'd Charge To Fully Recap The Amp. Old Timer spends ages Fault Finding to find One failed coupling capacitors, they feel so proud to have found one bad & replaces it. No consideration that if one Capacitor on a 1972 amp is bad, hey, the Rest must be nearly failing too. Better Deal for Customer to get their Aged Amp rebuilt properly, else the next faliure could be a year, back in, expensive repair & could continue for several years until the Customer realises their Trusted Tech is doing them no favours. Good for Repeat Custom, but Disrespectful when it should be clear a proper rebuild is needed. Take the 1970 Akai AA-8500 that was on the site ignored for several months, if we're glad as we thought more on it & now are keeping it, it's on our Speakers for Daily Use as we type. The Amp we rebuilt a huge amount including critical redesign, it all worked fine if the Tuner wasn't great on FM which probably puts buyers off, if Tuner work can be a pain as work may require realigning & we don't have the £3K of test gear. But Most Tuner work is possible, we rebuilt the Sony STR-6120 Tuner & the Trio WX400U valve tuner so the stages & needs are understood. FM Tuner low on one channel means a board needs recapping as the fault is there. No point fault finding one bad capacitor, redo the lot including some upgrades. Tuner now works better if not quite perfect so to recap the other boards makes sense. We don't know exactly which capacitor was bad & don't need to know as the board with new capacitors now. Straightforward job or spend hours Fault Finding to find the one bad one & leave the rest that are 49 years old. Now you see why it's a waste of money just to repair once an amp is pre 1980. We're getting quite a few 1976-78 amps failing as the blog above shows, since 2011 these have deteriorated as early sales by us showed these amps were still useable, but 8 years later they are failing. 8 years use is very good compared to new gear though.


Quad 44 & 405 Preamp & Power Amp New in 1979.

July 1979 has HFN/RR announce "At Last" as the Quad 44 preamp is released. You look down the page & see a early 1960s looking thing & wonder, but sadly this is what Quad offer as New 1979 Product. Still for Building into Cabinets, or using standing free & sliding all over the sideboard. Quad are Seriously Out Of Touch on looks. The Quad 405 power amp was New in 1978 & is just a plain box with a grille, perhaps better looking as Quirky, but the Quad 405 is dismal. The 1968 Quad 33/303 seems to have sold well, the power amp used by Broadcasting for it's small size. But the Quad 405 needs looking at. We know we'll not like it as beyond the looks it "makes extensive use of Integrated Circuits" so it's stuffed with ICs. To hear comments in HFN/RR saying the Grey Old Men think it sounds good again just leaves us wondering. Jan 1980 HFN/RR has Martin Colloms with a multi amp review in his usual dry way, the other amps are far from perfect if the Quad surprisingly is liked for it's sound yet there are quite a few issues that are pointed out a little too calmly. Eight Amplifier Review over 10 pages not including ads, but just abouut 1.5 pages on Subjective Opinion on a Group Test, what use is that? "Difficult Case" says MC, if adds the ICs on Input are Buffer Stages & they aren't Relays, they are small Logic type switches. Interestingly it shows the Quad 405 response curves including Tone. The 'Flat' Response curve clearly shows it's Tailored for the ESL57 Electrostatic, people still bought these 1950s Room Heater looking things in 1980 still & it just must have appealed to an older buyer rather than the much more attractive & useful Japanese amplifiers. Bass is flat down to 20Hz if then drops 5dB to 10Hz which is fine. The Treble is Not So Acceptable as a Hi-Fi item we say, it starts to roll off at 5kHz, 1dB down by 10kHz if 3db down by 20kHz and by 45kHz it's 6dB down. This is poor as it'll never give good Square Waves as these need Good Harmonics over 20kHz to give the correct shape. Maybe not a disaster, but clearly sound shaped. The Tone Controls are even more Non Standard, these are really Useless in terms of you buying a Preamp for any other speakers than the ESL57. Bass can get a Huge +15db Boost, it goes off their Graph even, boost centred about 40Hz to fill in the No-Bass ESL. Useful perhaps if why you'd need 10dB Bass Cut is a question. Treble is Ridiculous, this is giving just 2dB Treble Boost at Maximum in the broad 2kHz-10kHz range, not really a Treble Tone at all, just a Presence Boost, but just 2dB is hopeless. Huge amounts of Treble Cut including their Out Of Date Treble-High Filters. For those used to Vintage Amps with ±10dB Boost & Cut, the Quad 405 is of No Use. Circuit Design. It's easy to say "Quad are Garbage" but to explain why, the Circuit Diagrams, just of the Preamp, the Current Dumping Quad 405 with it's Error signal that runs too hot at higher power we've said of before. To get the 44 manual from HFE just now, we've not looked at it before, to surprisingly see a User 5* Review saying Tone is limited if it's Good for Vinyl tells a Newbie opinion. The Quad 44 manual on HFE has Loads of Modifications through the Production Run. That clearly shows there are lots of problems with the design, did they not properly use & test the thing? Looking at the PDF Page 29/36, the Tone Circuit, it is with 2 ICs & some design is truly awful, they clearly want to restrict the sound as much as possible, taming it down to sound "Small & Nice" yet Far From Hi-Fi as we see it. The Design is utter garbage, all those useless Filters, everything So Restricted. The Inputs board from Nasty DIN sockets has Relays which is useful, but again the ICs if what they do is vague, Buffers or Gain Stages? The Power Supply is pathetic too, just 1000µf Main Capacitors on ±, a Regulator pair as many amps use, but then they use 15v Zener diodes to get the Supply Voltage. Rubbish design & Zeners as Voltage stabilisers is very poor as are other aspects. The "Disc" input is for MM & MC via separate boards. Again the IC if 2 transistors for an obscure reason. The amount of taming here again is very disappointing, an awful design & rarely seen elsewhere. The Radio input, Line level again mangles the signal. The Quad 44/405 to us is Far From Good Hifi. We do not Recommend you even bother with this amp combo, It is one of the Worst Designs we've ever seen, it will give a small soft limited sound that is far from Hi-Fi as we see it. Everything is Tamed, Designed to Limit Treble & Bass, this Hides the Roughness from it's poor design & unresolved detail. We need a Beer after seeing this one, amazing what awful ideas these "Lifestyle" type Hifi systems force onto their Gullible Inexperienced Customers. It continued with other Cliquey Brands like Linn, Naim & Meridian. It's Sad to know people buy this junk even now thinking it's good when so many much better amps are out there, you can buy a £100 amp on ebay & get a better sound. This is why these amps are forever on ebay, likely the same amps being resold once the buyer realises they sound awful. Yet HFN/RR love these things, but to realise a guy like Donald Aldous was 80 at the time, to not want to try newer gear as it's not for them, brand loyalty was important at this time.


October 2019 Blog

Severe Overpricing On Ebay Is Now Spoiling The Scene.
We see how we've helped the Vintage Scene along a lot, together with useful info sites like Hifi Engine (HFE) with manuals. The idea of the Hifi Site was to let the World know that "hidden" amplifiers were good & revive them from obscurity. The 1973-77 Yamaha range, early JVC, early Sony, early Trio-Kenwood, early Sansui etc etc. We've helped give Many Amplifiers credibility & the pre 1977 era is very much alive as this era is where the Best Sound Quality is. Collectors have kept these amps, if mostly what you find are Attic Finds. All Aged Amps needing work, ones pre 1978 are now failing as parts age too much & amps don't work right, if most buyers just use them until they fail which is a bit sad as once they fail, damage could be extensive, a Relay, if fitted, will not save much as the "Protection" circuits aren't what they seem. The Bad Aspect is Greed by Sellers Online. The Reality of Prices & Sold Prices for Raw Grade Amplifiers is best shown on the "Hifi Shark" site. They list ones for sale on many sites Worldwide, but always check the Sold Prices & ones on ebay. It is known that some Sellers "Buy" their own amps to falsely inflate prices & relist, this does show up. But look on ebay to see The Overpricing on Buy -It-Nows. They put very high prices on Aged & Often Average Amps, the £50 amps of 2012 are often £300-£400. Ones we've rated for years are usually £600-£1000, yet theirs are Unserviced All Original Aged Amps. Blogs above show these amps are often on their last legs, yet the Pricing is Unrealistic. The Best Judge of Any Item is to see "Sold" prices & to see if they are genuine. There are a few sellers who Sell On Commission & their prices are often 50% higher than what they should be worth, as in Auction Prices. Greed often comes with Rudeness when you try to make a realistic deal, generally in higher priced items, the first offer is the best. Restored & Rebuilt Amps as we do are another thing, much work & new parts ups the price but done right you get a refreshed amp good for Daily Use, as we offer. Only the Reality of Not Selling will get these Overpricing Sellers to realise Aged Electronics only have a certain value, the bigger amps they realise are Expensive to Rebuild & this puts most people off as we've found & have altered our Email Form to stop dreamers thinking a Big Rebuild is £200 as they don't properly read our pages. Ebay allows offers on Items via Messaging, even if the Seller doesn't ask for Offers. Try your luck, but be prepared for Rude replies, they often Bark Back at you saying another is that price online. Not Sold at Double what it should be. You see on "Pawn Stars" that Sellers want say £8000 for a Rare Item, Pro Dealer Expert who deals in these things says it's only worth £2000 as not so rare or wanted today yet the deluded seller wouldn't take less than £5000, just walk away. We realise the days of Yamaha CR-1000 for £90 & plenty of our early amps under £100 are pretty much gone unless they are Not Working, but The Greed in selling 40-50 year old Raw Aged Amps like they are less old is getting a bit ridiculous. £800 for Yamaha CR-1000 raw, Sony STR-6120 raw, Yamaha CA-1000 raw. They're great amps but those for sale are way overpriced & often several the similar price not selling. A different reality is still how cheap you can buy good Hifi in Street Markets in Countries around the world as we hear. When Collectable & Useable items are Priced Realistically to Cheaply, more will sell & more will discover them. The problem with ebay, as we see with Records, dreamers putting £25-£50 on records worth £3 is common. Seller gets Free Listings so just keeps overpriced items running forever. One seller with a 1956 UK London R&B record has it in awful grade, it's probably worth £30-£50 as a 'filler' copy, yet it's been £250 for about 4 years. We told them they were way overpricing just to see their response, which was to put it up to £300 for a year. Other copies in better grade have sold for £100-£150 in the meantime. Overpricing their tatty amp or record at high grade price is a problem too, a £50 record in scuffy grade is £10-£20 if anyone wants it but they still put £50 on it, a JVC 4ch amp missing control knobs priced at 3x what a nice one is worth are examples. Also the Overpricing by not telling of faults, Amp Works but is so noisy it's not useable is not unknow, high price as usual too. Beware the Overpricing. We buy amps very carefully that we want & will rebuild, the reality of some amps like our Marantz 2385 is we bought it at the right price, yet our work has way overpriced it now, it's a huge job to rebuild & service. But we now want to sell it & we know the reality of pricing, sometimes to only make a small profit like "Wheeler Dealers" does, but without the benefit of being paid to make a TV show to cover the real costs. If buying Raw Aged Amps, be sure unless it's a real Rare one that's not on ebay USA or Germany, you'll find one at a better price in better grade than the one the seller wouldn't move on price with. We did just today as of typing & it'll be blogged about soon.


What Sort Of Hi-Fi Gear Actually Sells On Ebay?
Just click on "Completed Items" in how you search to Browse. Not done that in Ages, but the Results are certainly interesting. Ones we looked at have Sold, we thought not for us if are worth others buying who'd just use them, careless without getting them checked, but the reality is, the Majority of Amps & Receivers that sell are Under £100. We see AV Amps that last about 2 years before failing sell at High Prices as working, £600 now, £20 very soon seems the very cynical Reality. People apparently buying Naim Amplifiers, stuff we don't like at all, to wonder if they actually Sell or are 'Sold' to create Interest as we've Blogged on before. The Majority is under £100 with a large amount £50 or less. This is the Real Audio Scene, they buy a Cheap Amp & Use it until it fails, was only £50, who cares. Much like Buying a Car & Running It into the ground, in days before Severe Emissions Tests on MOTs people used to drive Rusted Out "Flivvers", Bangers or Wrecks. To do the same with Hifi. Not everyone has the Money of course. But they are generally buying Rubbish Amps that won't sound nice. The ones we looked at to consider the buyer will have a more worthwhile amp, but they'll never get it Serviced or Checked. Many will just end up tidied up & priced unrealistically, the amount of average amps overpriced at £300+ is a bit sad. There are some Real Bargains but "Collect Only" which is so naive, travel to Cornwall for a £60 amp is expected. After doing the Hifi Buying Game we've noticed people do Pack Them Better these days if often the descriptions are hiding huge faults, if sometimes the seller is honest to say it had bad problems, we bought a JVC receiver described like that & will rebuild it, if it's not really for many to Gamble like we do. Despite Prices being Way Higher than our Early Days getting good amps very cheap, there now are Sales on Gear that was Ignored in 2011-2013 before we Serviced & Cleaned up amps, if not recapping then & the Market saw there are Customers if you do things properly. We can see We Are The Ones who have got the Vintage Hi-Fi Scene going more than any other seller. Who would consider buying a 1972 Trio-Kenwood KA-7100 60w amp in wood case for £350, tidy amp, no inside pics. KA-7100 is All-Transistors if the IC looking part is a Double FET which is good for Matching. A 1977 era amp with less pleasing build inside isn't a type of amp we'd try, if it'll likely sound good & would upgrade well. We also saw a 1967 Trio-Kenwood TK-66 sell, the tuner not mentioned working or not, they are nearly always dead or will fail, so we left it alone remembering the last one had a poor Power Amp that was pretty lousy as made until fully rebuilt & redesigned like the lucky buyer of our one got. We only fully redid it to see how good it could be after getting a tatty one early on. To see several £500+ more Modern Amps selling, to think they are not buying wisely, the sort of amps we hear Customers had & swiftly got rid of on hearing even Raw 1970s amps for the far nicer sound. As with Any amp, what you read & hear others tell influences. Not sure many buy as we do, looking at designs to tell what the amp is, if some now look to avoid ICs which are best avoided anywhere in the Power Amp, if Preamp ones we've found more acceptable. What is noticeable is The Lack of many amps we've reviewed, just not being around anymore, if better selling ones at Overpriced prices put buyers off. Those buying Cheap Amps may get the Interest to look for Better, if as we found before buying amps to try, where do you look to find Qualified Opinion on many amps? Forum Opinions we used to read since getting a computer & generally the opinions are so vague based on little experience, so we thought to Write Up Our Opinions to share with the World & further a Scene We Like. This Concept is What Your Reading Now. Hope it Helps you Discover Lost Magic In Music that lousy sounding amps lost your Interest with.


At Last: A HFN/RR Letter Saying 'Quad' Sound Lousy.

Quad have been heavily sponsoring HFN/RR since the early 1960s, as the continual "Quad" front covers to the 'Hi-Fi Year Book', every year 1956-1974 had Quad on the front cover, the 1974 HFYB with the ancient Electrostatic ESL 57 must have got ridiculed as 1975 brought far more what people were wanting, a modern styled midprice Goodmans system. Quad got the ad facing the Editorial page similarly for decades. Quad Bias? Be sure of it. September 1980, an issue which goes to A4 size instead of the usual shorter & slightly wider size is a bit strange, to see not all advertisers were told as their ads don't fit. But the Quad letter in "Reader's Problems" matches exactly what we think of Quad, the 33/303 & 44/405 amps. The writer says "I Don't Care For Their Sound" and says they sound "Muddy with Top End 'Tizzy & Edgy' with a deadpan lacking in life sound with no real warmth to the sound". That sums up their opinion, they sound lousy with no detail or quality which is obvious from looking at their very tamed circuits. The writer is asking HFN/RR for help, having tried many other amplifiers, probably only UK made ones if no Brands noted. He say the clunky Dual turntables aren't much good which we agree with. He owns KEF 104AB speakers which sound good if the Quad really kills the sounds, as tamed for the ESL only as we've said before. HFN/RR reply is still with it's Head Up It's Backside about Quad & claims just about that all amps sound the same. In 1980 to still claim that after many tests to prove otherwise is shameful for HFN/RR to still state. Reader still wants to try Sugden A48 proving they've only tried UK amps. We tried UK amps early on & came to "not like them" for general poor design & build, typical British Workmanship. The far superior Japan & USA gear never gets recommended in letters, in 1980 they could have their pick of 1977-80 Japanese amps that were being heavily discounted. We'd say, "Yeah, Quad are way overrated & way out of date" and recommend they try the earlier Marantz or Yamaha that shops still had. Forget the 1980 ranges as too many ICs. The reply still fawns over Quad who will demonstrate etc, but Quad are Old Man's amps, sold to those aged 50-80, not the far more impressive Non-UK brands. They just say their amp must be faulty & can't possibly sound as bad without daring to admit the truth. The "Crossover" reply is clearly written by The Old Grey Men rather than The New Hippies who'd be Telling Him To Get Modern. Frustrating closed minds in Hifi still in 1980.


How Much! The Reality Of What Certain Amplifiers Were Sold For As New.
Comet really upset the Hi-Fi scene with Heavy Price Discounting. Several Major Brands got involved & Comet Ruthlessly Discounted as they grew Huge in Buying Power. Brands like Pioneer, Akai, Sansui & Rotel really had to Heavily Cost Cut to be sold so cheap. It's actually sad as these Brands lost Any Cred & Mostly are Best Avoided past 1974. Note Yamaha never got in with Discounters. Marantz only allowed their lower models, April 1980 has their Marantz 1070 36w amp for £90 now it was an end of line product. Pioneer SX-980 80w receiver for £380, Pioneer SX-1080 120w for £450. Rotel were way price cut & to see the Rotel RX-1603 180w receiver we had recently, priced at £250 is embarrassing, but it was now an old model to clear. Rotel RX-1203 was £200. The Rotel were slightly less in October 1979 ads even. August 1979 has the Rotel RA-1412 110w amp for £194 & the Rotel RA-1212 70w for a ridiculous £102. Letters in HFN/RR told that these Discount Stores were Notorious for Selling Off End Of Line, or Amps that got poor reviews, to appear to give the 'Mug Punter' a great bargain, so these tricks were quickly seen. In 1971 early Discounters picked up early Japanese Germanium amps from 1966-67 to sell off cheap. But it makes Good Brands seem poor & the build quality of the RX-1603 we had showed where it was cost cut to even be it's Original Sell Price. August 1978 has a shocking price reduction, the first real Big Discounting, the huge Pioneer SX-1250 160w receiver RRP £692, Comet Price £350. The Reality must have been The Monster Receivers like RX-1603 & SX-1250 weren't wanted by Buyers as too big sized & too much power. The SX-1250 is already much cost cut in a 1977 world where the Marantz 2385 was RRP at over £950. Today this sort of 'Huge Price Discounts' is often to trick the unwary. We wanted a new Kettle, RRP £70 it said, £25 to you & other ads offering at £70. But on getting it, to see it was really just a £20 kettle with £5 delivery, so back it went. This with Hifi was just the start of confusing the buyer with Discounts when really the 'suggested RRP' was pure fantasy. Unless gear is End Of The Line clearouts, be sure any 'Bargain' isn't what it seems.


What Is The Safest Type Of Amp When There Is A Major Fault?

The idea of a Relay on the Speakers, such as the Yamaha CR-2020 one you'd think would save your speakers & amp. Not so as proven by one we had with awful 1980s 3 leg Output transistors instead of the correct TO3 type. The amp must have got shorted, to assume the relay clicked in at some point to save the speakers, but half a second will have damaged the Output Transistors. Other Amps with Capacitor Coupling appear safe for speakers, assuming the output capacitors are good, not chancing 50 year old ones. The output capacitor will save the speakers you assume, probably this is correct as no high DC voltage gets to the speakers if stages of the amplifer power amp will fail. Capacitor Couplng won't stop a very loud "squeal" noise as we found with the 1967 Dynaco/Dynakit Stereo 120 when the main input wire got pulled out with the amp on. Result: trashed tweeter as the signal desite an AC sound was heavily clipped so appeared as high voltage DC which outed the tweeter. Sony TA1120 the early one has a complex slow start up with Relay & Protection. A 1967 HFN test actually purposely shorted the Outputs, Relay jumps in, Amp is fine again on turning on 2 minutes later. Impressive but it's not a Test we'd like to try. The 1971 Sony TA-3200F has No Relay & Direct Coupled. The superior 1973 later version without the Extra Protection board has 2 Stages of Protection it says, the Service Manual explains this & based on ones we see for sale since 2002 when we nearly bought a set, these are always in good condition, no spares or parted out ones, so the Protection must work well. The big 1976 Marantz 2385 has 2 Relays, one large one for Mains & then after a few seconds the Speaker one jumps in. This amp can be found in less good grade or much repaired, but the 185w power if not used safely must turn the Relays off Fast, if not Fast enough to stop damage. The Sony STR-6120 we fitted extra Fuses on two of these as the amp only has One Fuse on the Power Supply Board. The 6120 we have here to repair the owner unfortunately kicked the speaker plugs from the speaker & assuming the plugs were Metal Cased ones, it shorts the Amp. We only Trust the Plastic Cased Plugs, huge amounts of Bare Metal is just too risky, as Blogged before. The STR-6120 even with Fuses on 4 HT Lines still trashed the Power Amp Half, burning out Resistors & Damaging Transistors. It can be repaired if burn holes from Resistors Frying leaves a scar. To add Speaker Fuses is possible, but these would need adding into the Outer Case rear panel. The Old Type Spring Fast Blow Fuses aren't around, the Standard type of Fuse might not catch it in time. But how often do Outputs get Shorted on Amps? Based on all the Amps we've seen, it is not so common, if Amps of All 'Protection' Designs are liable to get Damage.


Which Sounds Best: Bridged Outputs, Parallel Outputs or 1965 Crazy Amplifier Design?
As Raw amps these sound much the same. The Reality of them Being Aged & Not Very Useable now isn't considered, opinion on rebuilt & upgraded amps is. 1965 is the Sansui TR-707A that we got another of for a customer so we rebuilt it leaving the main board until last, to hear how it would have sounded to a 1965 buyer. It was decent enough but quite tame. The Bridged is the 1973 Trio-Kenwood KR-6340, again very clean sounding by bass was disappointing. So hugely upgrade it as the 1973 Marantz 4070 when upgraded had a certain magic to it. Here with a better Tone design it brought the 6340 alive. Takes some time to put the 'Concept' into words, the Bridged Mode gives an Unique extra life in the Lower Bass & Bass regions. It has greater Depth & Separation when usually Bass sounds more Mono. The Bridged with it's lack of Ground Reference as it uses the Normal Output plus the Bridged Stage that's Inverted. So the Speaker sees 2 Signal Sources, like a { = } instead of { = | with the "|" being Ground. No Ground allows the lower frequencies to be freer without Ground getting in the way to limit the sound, it also gives Bigger Dynamics as Double the signal. An idea that needs deeper looking at. The Bridged Design is very clean on this amp & the Passive Tone adds an extra quality that the Baxandall NFB Tone can't quite get. After getting the KR-6340 Tone stage correct for our Redesign, to actually need to be careful with the Treble Tone as BBC with their Peaky Treble Microphones really can be too much which is a first to hear, voice Sibilants just too loud if not clipping. Slight Treble decrease brings it into line. Parallel Outputs is the Akai AA-8500. This we've not fully upgraded the power amp yet, though the amp is lively as it is. The Trio-Kenwood KA-6000 we put Doubled Outputs on & the Richer Sound is Clearly Noticeable. The AA-8500 is a design we can do more with than the KA-6000 so we're finding the AA-8500 does sound very nice. The big Marantz 2385 has Tripled Outputs, but the design is still restrained, we could redesign it but slightly wary of a very lively 185w on 50w Tannoys, 50w Continuous could take 100w brief peaks, but 185w is too high. Crazy Amp is the Sansui TR-707A, a truly outstanding amp if to get it to the standard of ours is extreme as so much needs doing. The design is early, based on Germaniums & with what sounds a Low Damping Factor, the TR-707A has an Unique sound. All three amps sound High Excellent, but to rotate them on Speakers to enjoy their differences is the current idea, KR-6340 more finished than the other two, but to keep Reference Amps of all three. The TR-707A design has inspired the other two & the Sony Pair blogged below.


Late 1970s Group Listening Tests In HFN/RR Magazine
In the Pursuit of trying to get Worthwhile Subjective Opinion, HFN/RR often used Panel Listening Sessions with about 8 people. The idea summarised after reading several articles is this Forced Listening was a Bad Idea, stressful, impossible to judge correctly & Too Many Cooks with differing opinions never gives one Educated Opinion. As said before we used to Test 10 Amps in One Day to "Pick The Best" but usually this was as Useless as Group Tests. The first amp was your reference & maybe 5 amps later one with a more Bassy-Trebly sound upset the Reference Opinion, even played with Tone Controls Flat, as we do with Headphones & our Source Material. Too many opinions causes confusion, the Brighter Amp will appear 'better' but later the more Neutral Amp sound will always Win Through on repeated tests & then using for days-weeks on Speakers. The HFN/RR panel tests were known reviewers & their wives plus the odd extra name. What Sound Quality Men like is often not what Women like, the more Dynamic sound of Hifi isn't important & to see Women in the 1970s were happy with a Cheap Portable Radio & even in the 1980s a Portable Cassette of no Hifi quality at all would please. This is just from the Typist knowing Family, another didn't like Bass as it Buzzed their Earwax. Hardly worthy Audio Opinions from them. The idea wisely was only used a few times & proved that more than one opinion, especially by those less experienced is just about Void.


Hi-Fi Magazines 1978-80: A Wasteland Compared To 1970-1977.

We've only got the HFN/RR to Dec 1980 if we had one of each year until 1990 & found the Magazine was really very marginal for items to interest, much like we've found the 1978-80 era, which shows shops more into selling Cheap than Quality. Monster Receiver Era? You'd barely notice it reading HFN/RR. Other magazines around at the time were criticised as "Hi-Fi Comics" as HFN/RR were only too pleased to print letters about "What Hi-Fi" type publications. The adverts 1978-80 are more into selling Junk like Graphic Equalisers, loads of Cassette Decks & Tapes. A 40w Amp by a known maker could be £100 or less, boring plain boxes. The start of Stack Systems in Chipboard Cabinets with Glass Doors, a few years before the Amstrad All-In-One Stak systems that had one fascia moulded to look like multiple units. The High Power Amps just about disappear. Then the advent of CD in mid 1979, it's all there but not released until 1983. We just fail to find any interest in the post 1977 era Hifi. By 1980 the HFN/RR magazine has very little to interest us. Amps of the era just low powered & importantly "Cheap" making amps of 10 years earlier seem expensive, and hankfully they were as well made with good designs & no cost cutting. Comet again set the scene with Amps so cheap by the Big Brands it's not nice reading. The amount of "Crap" in the 1979-80 scene is a real offputting read, Graphic Equalisers, Boring Basic Amps that have No User Features like Tone, Mono switches or even Phono. The Moving Coil Cartridge scene gets a Blog later on. Useless gimmick items, loads of Home Care products are cluttering up adverts. The Amount of Ludspeakers is as Confusing Now as Then, how on Earth can you decide between maybe 200 different Speakers? Price, Size, Power & Wife appeal was likely the deal. Review Articles try to compare loads of similar items together. One-Off articles about Technical matters if barely worth reading once you see Maths Equations. Oh, and then Digital arrives by 1979, loads of artilcles about that, Paul Messenger's 'Subjective Sounds' isn't worth reading either. A 1980 mag is loads of Ads, Editorial, News then some rambling boring articles, dozens of pages about Classical Cover Versions, even some telling there could be 20 versions of the same Symphony etc. Then comes Rubbish like Half Speed Mastering of LPs, Boost Up The Bass required on cutting if supposedly the Dynamic Range is better if 4 times the price. Further into 1980 the depressing scene of Music Centres with Glass Doors to stop you using the gear & seeing Hitachi were the first to the 'Amstrad' idea of one unit looking like 3 separates. 1980s Hifi was dismal if the Cheap Junk sold by the Truckload, if now Long since been E-Waste as it's just Disposable gear. Then the ghastly Cassette sold as an Important Item to have, sadly it was as the only way you could Record your Music to play in the Car. Car Stereos were still the Standard 1950s format with the 2 side Rotaries with the middle block unit. So much Excitement in 1960s & 1970s Hifi then the Mass Market 1980s Crap. It was Crap too, stuffed with ICs & as cheaply made as started to become normal by late 1978. There's still the odd interesting Stuff 1978-80 but it's very minimal, what stood out we've blogged on or will as a pile bookmarked to talk on. The 1978-80 era in Hifi News/RR is a frustrating one & having tried one of 1981-89 it only got worse as CD, Tape, Graphic Equalisers & others seemed more Important than Amplifiers, if those 1980-1989 have very few amps of interest to us & be sure we check out loads of Amps by looking at Manuals to see if there's anything worth trying.


Sony TA-2000F & TA-3200F We've Not Mentioned These Much This Year.

Not mentioned these much this year as the last opinion from around Dec 2018 was that FETs weren't very good in Audio circuits. The TA-3200F is World Class as our Upgrade & 1µsec Rise Time is very impressive if one late 1970s amp quouted 0.6µsec. The Power Amp using the much upgraded Sony TA-1140 as the preamp, putting Blanking Plugs on the 1140's Power Amp input to not upset it, the 1140 pre & 3200F power amp were very impressive, the 1140 amp stage at 40w or so came close. The TA-2000F volume control, as with some Sony is just not very good, the slow taper on low volume means it needs to go near midway for a decent volume & then goes too loud too fast. We got the Alps Blue volume control & found the previous owner tried the same as the cables were cut but resoldered loose. The TA-2000F with the Alps is Not Much Use as it goes too loud on just a small rotation. TA-2000F has too much gain, it sounds hissy & too much gain loses finesse. So to alter the preamp to have the gain match right. Finding that Sony put far too much Gain & the Silly Volume Control Taper is offputting & the amps sat gathering dust really since last December with the odd try, but not having much confidence with it. Blogs tell of recent amps & after playing the Marantz 2385 to at least try the Sony Pair. Had toyed with selling them, but the Power Amp is too good so leave it for another time. The TA-2000F still needs alterations but the last 2 days on the Tannoys for TV had the amp sound impressive, if not altered since the Alps change. The Opinion on FETs being fine or awful therefore is currently nearer to being acceptable, if the design being overloud & losing Finesse certainly made the FETs seem bad. The Sony TA-1130 has FETs in the preamp if the amp was more dry sounding. It's probably just how they are used & the TA-2000F does not have a good design as original. From listening to some really great amps this year, the 1965 Sansui TR-707A, the Trio-Kenwood KR-6340 & belatedly the 1970 Akai AA-8500, to hear different sounds & ones more advanced. The 1976 Marantz 2385 being one used often too, if now seeing where it's still limited, what to do with it also. The Sony Pair sound very like the Akai AA-8500 a more Neutral sound if far from Warm & Slow with Redesign. All this Redesign takes ages is the Reality, for a Customer to want these sort of High Upgrades sort of Outprices the Rebuild-Upgrade game & for Amps to sit ignored 9 months isn't viable. The Akai & Trio-Kenwood sat ignored for sale for 6 months similarly. The Story of The Sony Pair will continue. Those thinking to buy these amps need read our Review, Preamp is very limited if the Power Amp is decent as Original. Just looked on ebay to see if any Sony TA-1130s around, last look a year ago there were ones £300 or less, yet now a crazy £1700 on one from Japan, not recapped even sadly shows how messed up pricing is, despite £300 & £349 in the clip-woodcase being Summer 2019 sales.


Our 2011 Bought Sony STR-6120 Here For Repair. A Chance To Play It.
A chance to hear this same 6120 we got from Canada in late 2011 from parting out the earlier one, enough to buy a high grade 'Aux 3' one as on the Solds Gallery. Had Quite A Life this Amp as Blogged before, but these Amps are Forever Repairable & despite a Speaker Plug kicked out to Short & Damage one channel. It makes a mess sadly, burns resistors that burn the board & trashes Transistors. We added Fuses on this & another to try to save it from faults, if it unexpectedly it didn't really help. Looks smart again with a scar is the outcome. Get to play it again, very Wide Stereo. This amp has all New Resistors on the Amp Stages & this does make quite a difference to the sound. Just before we played the 1973 National Panasonic SA-6400X that sounded great if a little treble rolled. The Sony took a few tracks to 'tune in' to it's sound & now it's on The 'Correct Head EQ'. Lively Bouncy Smooth Detailed Sound. Does sound a little Brighter than other amps we've played recently, ie Marantz 1122DC as original plus the 1965 Sansui TR-707A. It could be rolled off like the Nat-Pan if that'd lose the fresh sound. It's a Low NFB design, these sound a little brighter on Headphones if on Speakers they sound right, if want at least 12" speakers to do the amp justice. Hearing the amp again, it could perhaps do with a little more finesse or some redesign, but the Customer clearly likes the amp a lot, so we'll not alter it, if to run it in for hours to see it's reliable. Later Circuit-Gazing shows the STR-6120 design isn't ideal to do the sort of upgrades the TR-707A has inspired & looking at other amps it seems there are few that can. The STR-6120 can be a real pain to get working, plus the wires keep coming loose if moved too much on the boards, yet once it's right it's reliable. The loud treble can get a bit 'eek!' if played loud on Headphones, Tone set flat, the reality is this is where it starts clipping off. 50w amp needs 95dB speakers to be it's best. Still one of The Best Ever Receivers, if they are 1968-72 made now so always need work. To go as far as we have on this brings a rather tired aged amp into something very special, see a 2-part STR-6120 blog that was another amp, not this one.


BE CAREFUL.. Who You Send Your Amplifier To For Repair or Work Done.
A current Worrying One on ebay.USA is one who claims to be able to Rebuild the Big Marantz receivers, 2385, 2500 & 2600. They put glammed up photos of these receivers. The "Deal" is very vague, $50 buys "Two Hours Work" on your Receiver. There is No Pricing Guide for those who claim to be Marantz Experts. We messaged them, they didn't reply as we asked what the full price is, if a belated reply saying the $50 buys you their time to price it, but never giving any idea of pricing. Their idea appears to be where you cheerfully send your Big Marantz Receiver to them, have no idea what it'll cost and just accept what they tell you, it might be $500 or $5000, who knows. There are always unknowns in amps, but one Skilled can still give a price range. These may be offering a Legit Rebuild, but the Reality of Vagueness & Egos is you may probably never see it again as they hold it hostage until you pay what they tell you to. Therefore it is in the Category of "A Scam". The Feedbacks where they claim many years doing this since aren't really true, their template website only registered 2014 if they've Sold Hifi if the ones Claiming to be from their 99c LED refit to $50 Rebuild are all Voiced in the Same way. Not hard to "buy" your own 'service' & create Feedbacks based on nothing. No Customer would just send the Amp without knowing an expected price. We try to price jobs if there is always the unknown if there is Damage or Faults. The more amps we do, the better we can price them & often our quote is matched on seeing the amp here. Some amps could cause far more work if to keep to the Price. We don't do Doorstep Drop Offs as this is ridiculous for a Customer to do, to just leave it at a Street Address, so Courier only is how we do it to keep a paper trail. There use to be £99 Repair Service ads online, these seem to have vanished. Vintage Gear is Specialist, TV Techs of Today have no idea as it more than Board swapping. Other Ebay Sellers offer Parts Kits for those who think they can do it themselves yet are only in a Beginner skill level. You can get whoever you want to work on your Amp, but to Trust someone who Won't Price, Not Knowing if you'll See the Amp again or if they are able to even do what they Claim to is Risky. Beware cheaply made Template Websites claiming to offer any Paid Service, these can be Fly By Nighters who get one deal, such as the rather dubious Crowdfunding or Investment schemes, then Branch Off into another Company with the same team, if dissolving the old company.


1960s Trio-Kenwood Receivers Are Selling.
Saturday 12th October we see two Trio-Kenwood receivers sell. The fact is only we have told online on several models that these are good, so the buyers will very likely be readers. These amps were unknown & ignored in 2012, good Progress to see these old receivers now get considered worthy & bought. TK-140X with the Silver label earlier one & a KT-77 28w one in the KT-66 range from 1967. We looked at these, the KT-77 was listed just 10 mins before it sold for a Bargain £40. What the Buyers think & actually get with 50-52 year old Hifi is the unknown. Tuners on these 1966-69 Receivers are notorious for not working, the TK-66 FM Tuner did work & we heard it fade away to silence that stayed silent, sometimes FM is gone but AM works. Trio-Kenwoods we've had, beyond Tuner stages either work well enough or are too far gone on firsat try, just like any pre 1970 amp & pre 1980 ones are starting to get that way. The TK-77 looks much like the TK-66, we rebuilt the whole Power Amp as pictured on the Solds Gallery which much improved it, as original it wasn't so good as reviewed. The TK-140X Silver label has an earlier 2-tier Tuner & the same Power amp board as the KA-6000. Whether the Buyers will Recap them, TK-140X is a big job, or even see what a Rebuild will cost is another thing. Nice to Buy Them Cheaply or at a Reasonable Price, if the Rebuild is the Reality they need to consider. Three More We Saw But Bypassed. Looking for Interesting Amps or Ones To Rebuild. Yamaha CA-810, only one down from the big CA-1010 we had. Circuit much better without the CA-1010 preamp mess, but look at pictures inside online, it's not got the Quality like the CA-800 has, one board on the amp floor & random bits around it. Will be hard to work on & despite 65w the build quality puts us off. Non Worker goes for about £135 which is cheap, but doesn't exite. Yamaha CA-2010 goes for £500 the same day, looked at this in 2012, 27 Transistors in the Power Amp is way too much. Same awful stack of Differentials on the Pre-Tone. Thin harsh sound expected, certainly as original. Then a Pioneer SA-7500, a 40w amp for £80. 'Untested' bleats the seller, feedback tells they're lying, they know it is damaged so it'd be another big project. Two below the SA-9500 that we've had a few of. Nothing too exciting knowing the top model so didn't really inspire. Probably that's the thing, We've Had Most Good Amps so the lower models don't interest too much. Buying Spares-Repairs Non Working Amps is a Big Gamble. Never Believe it's Untested. Likely it'll be a Recycling Centre Find & be sure These 'Dumpster Divers' know just enough to get an amp working if it will be able to, to see their other items reveals them. Sunday sees a 1971 Hitachi SR-1100, an amp we've not had since 2012 so maybe the review isn't as conclusive. It's a rare one so we never found one to revisit. We've got a NOS boxed one here to recap so it'll be updated soon. Ebay one in high grade makes a very modest £90 is what an amp with no deep writeup can get. Only a reader of ours would even know it's worth trying, but we can't buy every amp, if weren't around to bid at the end & probably would have won it. Maybe we'll see it for a rebuild, it is 48 years old & can be much improved.


November 2019 Blog

Hi-Fi In 1960-61 and A Quick Look at 1956-59

We've already Blogged on 1962-65 in 'Hi-fi Digest' blogs. We had the Full Set 1956-80 of the Hifi News/RR mag. We've sold 1956 & 1957 that were The Mono Era & really didn't hold anything much worthwhile except Garrard 301, Tannoy Speakers and Quad Pre-Power once it became Stereo. The Summer 1958 Stereo Launch was swiftly considered a Rushed Mess as Manufacturers rushed into making Stereo Gear that wasn't of the Quality of the Better Mono gear. 1959 had a craze on Tape Machines, probably more Advert Driven than Sales of the Cumbersome things. There's really not much pre 1960 that you'd ever want to use today, rebuilding the early amplifiers isn't worthwhile, to redo like-for-like gets done but the designs are too modest to upgrade. The Hifi Scene in UK only starts to improve with the introduction of Continental & USA brands as the 1962-65 era shows, the end of 1959 brought relaxed Trading with certain Countries. After the desperation of the 1980 soulless era, to try 1960 era magazines. Back into a very different world, selling Hifi to a few hundred people. The Feel Of 1960 after the depressing 1978-80 magazine era is really refreshing. To see the old gear that in 2019 you'd not really want to use, all those ancient amplifiers, prehistoric tape machines in Rexine covered carry cases plus much that seems so crude today. But back in 1960 when these were New, the idea was they were The Best seems right, if not for long. Stylish Adverts are more interesting than the Goods. The USA scene was far advanced to the UK one, where Integrated Receivers looked great compared to the Home- Made Build-In-Cabinet idea of Quad & Leak. Readers sent in Photos of their Hifi, built into their cabinets. Nearly all look awful today & the idea of the control preamps low down & turntables in a well is probably why these survive in good visual grade, hidden in cupboards & rarely used. The Adverts rarely change from month to month, there are Cocktail Dress women in adverts to show Woman Appeal for these things, have a party with a Tape Machine. The magazine seems far more Personal, like it's aimed at just a few hundred readers. "Johnny Staccato" in 1959 was a Jazz Hipster so had the USA versions of Hifi & this seemed to be the scene into Hifi. Records they review are predictably Classical Cover versions, a fifth version of one gets a review, plus reviewing those sort of Quirky LPs that made Hifi Sound Good. The letters page in an awfully polite rambling way, lots of words if little said & plenty of Circuit Diagrams for You to Build your Own was a large part of the Scene. Beyond the big Names there really wasn't too much choice in 1960 if you went back nearly 60 years you'd not be lost with what there was. Whether it sounded better as new, needing all those filters & rough Ceramic Cartridges on crude arms, just call it 'Historic' if the Records at the time were far better quality than replaying gear. British Hi-Fi claimed to be "The Best In The World" but the reality of the early 1960s was as the USA & Continental brands arrived, they upped the Quality in Sound & Looks. British Hi-Fi stayed much the same & got left behind.


FM Tuners: The Early Switched Type.
Rogers were the main makers of these early Valve Tuners from 1959-66 it seems. They were fine for UK Listeners who only used the BBC Home, Light & Third channels. But as better Radiograms showed, you could miss out on lots more from Continental stations that were labelled on Radiograms for three wavebands, MW, LW & FM-VHF. For the fact that BBC in 1967 changed to Radio 1-4 meant if in 1966 you bought the matching switched tuner to go with the Cadet III or HG88 III then your Tuner was useless unless modified. Explains why these are rare as long obsolete. The USA-Japanese Tuners or Receivers used the full 88-108 range & beyond, the 1963 Trio WX-400U goes 80-108 MHz, or 'MC' Megacycles as it was pre 1967. Similarly the 1970 Sugden 'FM Tuner' as on our Solds Gallery had presets if a proper dial, the presets needed the case taking off to set, very crude looking gear for 1970 as was typical UK product.


Custom Work On Amplifiers & Receivers.
Most Amps Recap, Upgrade & Rebuild well to give a Quality Product, the more Custom it is, the Better it can become is the Idea. But we don't usually offer Deeper Custom Work beyond what you See on the site already. To Experiment on a Customer's Amp is a risky thing, but we do on our Own Amps just to see what can be done. Risky work can get Tons of Problems as well as Give Excellent Results. It's far too unpredictable to Price on a Job & we find some Customers are on a Budget that sometimes is just too low to Do A Proper Job. But on the other side of things, it can Take A Year or more to get the Best From An Amp. It can go too far or need redoing again as it's not quite good enough. The 1969 Trio-Kenwood KA-6000 is an example. Ours is Very Custom with Doubled Outputs, had it about 4 years now, a Different Amp Board from a later Amp. To be forever trying to get the best from it yet find Poor Design as Original is the Limiter. The 1979 Luxman LX33 we've had 5 years & just this Month did some heavy Redesign to make the Amp a LX33 shell & TXs with Our Design replacing their awful design that they have the nerve to brag about on the Fascia wording. 5 years to redesign, rewire & improve is hardly a job we could do for a Customer. Circuitry needs Changing as is Redesign which takes ages to think out & try to get to peerfect. 1973 Yamaha CA-1000 is another one, here a year now, the preamp is lousy if it took so long to perfect it if still to fine tune it & then sort out Noises. Then the 1966 Akai AA-7000. We had this, sold it after doing a ton of custom work, but get it back earlier this year & so far have rebuilt to redesign loads of it, just for the trying of an unique design. One amp that arrived late 2018 really shook things up. The 1965 Sansui TR-707A has to be The Best Amp ever, but the thing is the Rebuild on it is extreme, it needs new resistors throughout plus much more including Tuner to recap. But this Amp despite loads rebuilt is still on the Original Resistor Values circuit if Our Upgrades really brought it out as Blogged & Reviewed. To do a TR-707A to our standard as we've had playing on speakers for most of this Month is a very big job for all the planning & work involved, Circuit diagram but no Board Layouts needs a lot of Learning The amp you can buy from USA to get to UK for about £300 inc Shipping & Import Fees. But a Full Rebuild to Our Standard is a lot more than a £1000 job. But for the Customer who wants it done properly, we can do it. Those who are on a Tight Budget shouldn't get involved with these Aged Complex amps, but Based on the Price of the No-Tone, No-Phono & lots of ICs High Damping Factor Junk New Today, the Buy & Rebuild Price is a Great Bargain for the Sound. Those 5 amps are ours currently, two are keepers but what for the Other Three? Since typing we've got a 1973 JVC VR-5525L receiver & a 1970 Sansui 350A receiver, both only 20w but these are still interesting amps with good looks, so well worth trying.


December 2019 Blog

Obscure Pioneer Receivers SX-2500, Pioneer SX-6000 & Pioneer SX-9000.

Receivers as an Amplifier with 'Built In' Tuner were usually the Best Seller in our 1965-1980 era. The earlier ones were higher power than Amplifiers, the Receiver with it's Tuner Dial & Controls often looks a Lot More Retro than the plainer Amplifier. The Receiver usually outsold the Amplifier versions, even the 1977 Yamaha CR-2020 outsold the varied higher power Amplifier versions at the 1977-79 era. Many who prefer the Amps end up getting the Matching Tuner as they go well together, many Amp & Tuner Combos even lower power do go well together. Back to those Pioneer... SX-2500 84w per channel into 8 ohms. £337 plus VAT in 1974 HFYB, it looks like the 1969 SX-1500TD. Preamp has a FET on the input. The rest of the circuit shows this is probably the Most Advanced Pioneer as many features in this one. 92v HT is high & the diagram says 85w/8 ohm. This one we get Jan 2020. SX-6000 is £221 plus VAT if no info. We got the manual in 2017 if didn't buy. Looks fairly like 1969 Pioneer if a Passive Tone here is unusual. Pre-Differential & the Power Amp is a tidier design than the 1967-69 ones. Would consider this worthy if the Power amp on heatsink plus output caps like the SX-1500TD can be messy on old repairs. SX-9000 is 62w into 8 ohms at £303 plus VAT. 50w into 8 ohms both channels is the real rating. These are all still around in 1973 as the "Comet-fied" Cost cutting on the SX-828, SX-727 etc begins, if SX-828 at 75w into 4 ohms is £285 as our Gallery Pic shows it still has Build Quality, if the SX-939 quickly replaced it, this still loooks well made but is very cost-cut as we found. HFE says SX-2500 is 1970 with 72w, SX-6000 is 36w & looks c.1971 style, SX-9000 has board info if no Schematic, 50w & 16.7kg suggests Quality here, lots of boards & ICs only on the Tuner. Looks good & would consider it worthy if unknown on the circuits.


European Amplifiers: Where Are They?
We've mentioned this before & last year tried a Revox and an early Grundig as blogged & reviewed. We didn't like either so got rid of quick. The trouble with EU amps is the Build Quality, the UK brands similarly. Designs are not to the standard of Japanese & USA brands until these EU brands got "Made In Japan" in later years. They use crude TV grade components, axial lengthways capacitors that are very hard to recap & they don't allow better quality capacitors. The Biggest Issue is DIN sockets, UK buyers do not like these. They are a Crude if 'Idiot-Proof' way of connection. The DIN input cables are OK but they still use unshielded cable which affects Cross Talk, not so bad if just using the Input cables, but Tape etc with In & Out is far too busy so they aren't really Hifi quality. Speaker Outputs on DIN are again Safer but that depends on the Cables being good, never use Old DIN Speaker Cables. DIN Speaker is OK to 30w-40w but look how thin the cables are, over 5m lengths will degrade the signal on 20w, with 40w more than 2m seems a bad idea. Some amps use DIN on 40w+ that we see is not a Hifi standard. To replace DIN sockets will just make a mess on the amp so don't try it. We write this as a reader liking Kirksaeter receivers wonders why we've not mentioned them. Firstly their availability in UK was very limited, only briefly shown in 1968/69 & 1970 HFYB. Looking at online Manuals they have that typically Cheesy Lego looking build look yet two of theirs RTX 7000 is supposedly '110w', RTX 8000 is '140w', RTX 6000 is '90w'. But they are lightweight 10kg amps, the ratings need more weight in the Transformer. The User Manual shows all DIN sockets with DIN for 140w Speakers? We don't believe the Power Ratings, a Spec sheet says 140w but it's going to be 2x 70w, these are late 1960s specs, even 70w RMS into 8 ohms is unlikely, EU use 4 ohm speakers so we reckon "140w" RTX 8000 could be no more than 40w x2 into 8 ohms. Beware the Misleading ratings. But even at 40w using DIN speakers & 10kg weight, we don't see the quality here, non UK text will alienate many too. EU Folks do get their own brands that don't cross to UK or USA markets, to like them for not knowing better is often the case. As with post 1980 Amps & Receivers, we'd like to find good EU ones & did try last year. But the quality isn't there, no point trying to Rebuild these as we can with other amps. Even the mighty Braun CSV 1000 that is a big money amp just for the Style Aspect, the circuit is pretty average. Google shows Kirksaeter are mostly a typical 1980s-1990s Mass Market Speaker brand, the usual multi drivers that aren't very good, seems a German version of Goodmans or one of those other UK midrange brands. The RTX 2000 pictured looks nice in a quirky way. On ebay a 1973 Kirksaeter RTX 85-55 is shown. It looks crude inside, $349 from the USA. Not the sort of gear we'd buy as we'd need to Rebuild it. For a Customer wanting one rebuilt, as with other EU & UK amps, to be concerned the amp couldn't take the upgrades due to substandard circuitry is a real issue. The big Tandberg TR 2075 we've looked at before & similarly don't see the Quality to build a Good Upgrade on. EU gear is built like Radiogram Innards, seen several of the big Brands to see that build quality doesn't improve on what are claimed to be Hi-fi. EU Hi-fi can be related to EU Cars of the Era, they may have some Charm but are very basic. No UK or EU amps ever rose to the Quality of Sony STR-6120 is the reality.


Considering EU & UK Amplifiers Differently.
The Best Quality Amplifiers & Receivers are the Japanese & USA made ones from 1963-1974. Past 1975 there are only certain ones of Good quality in a market when cost cutting & selling very Low Price Audio was the Deal. Hifi went very commercial by 1979 & by 1981 there is very little of quality left. Good that Music was getting played more if there was always a need to sell Cheap Hifi but to pretend it was better than it was seems cynical, read the Ads of the time. To be Fair to the 1963-74 EU & UK amps, these were Popular & for the fact many are still around in some sort of Working State shows some were worthwhile when plenty are not worth the effort to get going. You can't deny the build quality is very crude & primitive on many, Tandberg TR 1010 35w receiver shown up close by one seller after having done some repairs. Tandberg given good sales hype "Once A Tandberg Man.." but a man who doesn't think too deeply we think, like the Austin Allegro driver. At the same time Armstrong & Quad hyping theirs as "the best" when in the early 1970s the Japanese amps were way ahead. These are getting Old Now so Need A Proper Rebuild, just replacing a few parts will only bring more Repairs soon. As the Tech who'd maybe be rebuilding these amps, the work in these messy built amps will make a more expensive job & again are they good enough for high quality components even to recap let alone upgrade. We don't like doing Jobs that won't give good results, you can never tell what 'Secret' hides in any amp if many amps we do like there are some we'd avoid now. These EU Brands were Popular in their day & much liked, but as time goes on they'll age & opinions on the Quality as with Cars of the Era will change. We found one site... hifishock.org that asks Is The Amp Of Good Quality yet only shows inside photos. Sadly no Text but it lets us see Build Quality as do many Google Images searches. Photos are helpful but having the Amp here tells so much more, if it helps narrow things down. The Goodmans Module 80 we tried to rebuild, it looks tidy inside but the circuits are crude once you get in deeper to try ideas that work well on Sony amps for example, on the Goodmans it was laughably bad with instability & silly noises beyond just RF, cheap TV grade components limited bandwidth as original. To risk getting poor results on UK & EU gear is a Big Risk now we know it. Past 1980 things in UK & EU amps change, they start to be Made In Japan as were Leak from 1978. The 1985 Dual DV 1460 was a Japan build, a lot better than EU build if still with some quirks if it sounded Good on Speakers, we consider it good progress. As with any amps past 1980, risk of ICs, budget priced gear & a deep search to find Quality is the Unknown. We'd like to know of Good Post 1980 Amps we can Blog about.


Too Many Sellers Of Hifi Rubbish On Ebay: Who Buys It?
Quite a few sellers appear to get Smashed Up Amps from Recycling Centres & put them on ebay. The worst one we've ever seen is a Sony TA-1130 as on ebay currently. The Turd of a Seller wants £200 for a trashed amp. It's not worth £50 in parts as most parts are Smashed Up. Seller has 13 negs so clearly there are Mug Punters buying his Rubbish & finding out they were Conned, yet they're a Top Rated Seller which shows ebay cares zero. Plenty do rake through Skips & Dumps for gear to try to sell, the way the World is, ultra bottom-feeders. Their 300+ items for sale all look like E-Waste hoping Computer Based Electronic items are worth a Cash Strapped Buyer going for. Never Buy this Low Grade Junk Stuff, it'll be in Your Bin within a few days once you see it is trashed. The Sony amp is filthy, bits broken off, damage everywhere. Clearly a Council Clearance of Abandoned Property of those who never cared for it yet had what was once a Great Amp. To have Bad Negativity from Trashed Goods should not be Invited Into Your Home & it'll never be any good unless you buy another amp & swap all the parts which is pointless.


Oh It Only Needs A Little Repair Anyone Can Do.
This little Lie you see fairly often on Hifi Sales. We get lots of Messages about amps that are Failing, mostly 1970s but now even the 1980s & 1990s ones need work, but if it powers up & makes sound despite hiss & hum, it'll do. Seller tries to explain faults which is good, but brushes them off as Minor. We know what the Amp really needs so look at it with Eyes Wide Open. To regularly buy & get Customer's Amps, what we get is a Tired Amp. It may work, but too many Problems for a non-Tech buyer. The Hiss, The Hum, Very Noisy Controls, One Channel plays lower volume, Crackles in Use & other types of issue that generally means The Whole Amp is Knackered. It can be rebuilt, as a 1971 Sansui 350A we recently got, seller fairly tells of most faults but realistically the amp is only good to Rebuild, you can't cut corners & just Repair as it'll just go wrong again elsewhere. Those who still use original 1967-1980 Hifi without any serviving or work done are 'lucky' to have it work, but it'll be well below spec & once it fails, it'll gt expensive to even repair.


Ebay Overpricing On Aged Unchecked Hifi.
This just keeps getting worse, the Buy It Now amps offered at unrealistic prices, often higher than we've sold Rebuilt ones for. These Amps sit realising it's not selling as too expensive. The High Prices offered on pre 1979 gear is a problem, these are mostly With Problems now yet the Seller never tells the truth, a Yamaha CR-1000 we got from a customer paid top ££ for it yet it arrived Hissy to him. He didn't get any help from the seller as in that 'Ha-Ha' way, if there are ways... To buy 1967-1972 era amps they are Always Hissy. You get the Idea, you're Buying Blind & get sold a Turkey that does work but is unuseable. The 1966 Pioneer SX-800A valve amp was sold as Working, it did but you'd never trust it with Severe Hiss, Hum & Crackly Noises, you've overpaid, but if an item is Rare then you Buy it Aware it's Knackered to get it Rebuilt. There will come a time as these amps age to not even work, the last 10 years has aged amps we like a lot to make them not safe to use. Once these Overpriced amps start to fail as they will, prices will become more Realistic as the Amp needs work & to be bought by one who'll get it rebuilt. 1971 B&O Beomaster 3000-2 offered raw at £395, they say Tuner aligned but these were always in bad grade inside for the cheap capacitors. Buyers really need to be careful buying Vintage, to just plug in & use is getting amps failing too often now. Not to want to Scare Newbie Vintage Hifi users who think 40 year old gear is safe to use unchecked, more tell a Reality, but a lot of the Hifi on ebay is not recapped or anything & from all the amps we've had, very few in the last few years we can dare to try briefly on speakers to see what they are like as Original. Sansui AU-999 a 50w amplifier with far too many controls & obsolete hissy transistors, amp needs a full rebuild, yet £795 you can buy a raw one for. Big rebuild on this one as we found on our one, it should be £300 tops in reality. What do Buyers do with Tired Old Amps? The Vintage Hifi Market is still evolving, the interest in certain amps that need a £1000+ rebuild quickly stopped interest, yet these same amps are still Overpriced on ebay. The best ones are well worth the Spend. Sansui AU-505 a 12w amp from 1972, basic but worthy, but who would pay £200 for a not working one? Numbers don't add up, to buy at £50 or less in reality. A working one £180 may tempt a buyer, but remember it is 1972, these can work fine after Servicing, or use a few times & hear it go bad.


Hi-Fi Year Book 1956-1981 & HFN/RR Mags : How Essential Are They Now?

These books showed the Hifi Available in the UK 1956-1981. Started off in 1956 by only showing items the Editor considered 'Hifi' which was good in helping define Hifi. But by 1959 they'd bowed to the Advertisers & listed Tape Decks of below Hifi quality as these sold fairly well. The early books had articles worth reading if ones by c.1970 were very dry, just fillers with too much Maths Equations. These books still trade, they usually sell £15-£25 each if some years are rare & a 1981 one sold for £85, rare it is but not an interesting book at all if early Video Gaming may interest beyond. We've had & now sold our set. They are great books on reading Amplifiers & Receivers if interest heavily drops off looking through the rest. Hifi systems, consoles & stack systems may look Retro now but beyond the Expensive ones can't be many around. All those corny Repro Antique Styled cabinets hiding Hifi behind doors seems so Quaint now. Our site lists Amplifiers & Receivers Sold 1956-81 from the HFYBs. The specs listed are often wrong needing a second look online to be sure what Wattage the amp is. The years Post 1970 are stuffed full of Hifi & Related Items that are not really of any interest now. The Loudspeaker pages, in Enclosured era meaning a Complete Speaker in the cabinet again are stuffed with very mediocre items under 20w. Maybe someone will do a List of Loudspeakers by buying up many of the best ones & do a website. We'd think this would be a Waste of Time & Money as there really aren't many Classic Speakers, too many with 3-Way driver that never sound good & risk Bad Impedance Dips. To look at the small B&W photos does help, unlikely the scanned DVD versions are in crisp quality from ones we've seen. To be without the HFYB set isn't a problem, not looked through them in years beyond the odd look-up if a Customer has an old speaker, if today much is online including our Digest of them. The Hi-fi News & Record Review Magazines we've read through twice, it can be interesting & it can be a chore-bore. The Ads can often be the Most Interesting Bit as with the Year Books. The HFN/RR is great to get a Real Feel of the Era in Hifi, but they aren't essential & those paying £10-£15 for a copy with a liked Amp etc in will be disappointed at the mostly worthless reviews pre 1976 & then mostly confusing ones after 1977. The HFYBs don't take too much space, if the 1956-80 HFN mags are a pain, those weak 'Flyt' folder boxes to store them in but be too big for filing cabinets or shelves. UPDATE to get the 1956-1980 CD of scans of the books. These ae decent enough with pictures clear. The 1981 book is rather dismal for the Real Lack of Good Hifi so you're not missing much. 1976 & 1978 are smaller .pdf file sizes so photos less good. The set for £11 instead of a pile of books we rarely looked at is still worth having if it bdoes miss one issue.


1970s Music Centres & 1980s Stack Systems.

The HFYBs show Music Centres, a flat wide Sideboard-filling Unit was very popular from the Mid 1970s. Record Player, Cassette Deck & a Tuner Amplifier plus Speakers that were always best upgraded if many came as one Set. We've known these in the 1980s & the better ones were actually pretty good in context of One-Piece Systems. To see Ads of them to remember them fondly, but not to want one. Knowing a 1977 one in 1984 it was still working fine, but now 1977 is 42 years old, the unit may look appealingly Retro, but there will be many problems as are happening with Amplifiers. The Cassette deck needing new belts was a problem we knew in the early 1990s, if today you will have a job buying them as Rubber you can't use NOS ones as they will have aged. The amount of work to get a Music Centre working right & being Use-Daily Quality will be a big job. What do those buying these do with them? Probably a lot of these long since binned, even the big chunky Panasonic ones we remember from getting in the early 1990s were cramped up, made mostly of plastic, STK IC power amp blocks & likely to be TV grade components. Stack Systems arrived around 1979 with the initial idea being Seperates in a Chipboard cabinet with Glass Doors. These will take apart & fix like any seperate, if with the usual issues. Amstrad by 1980 made one piece units to look like Seperates but weren't. Even seeing these mid 1980s, these were cheap & nasty items that chewed up tapes & generally sounded lousy through the cheap speakers, if probably sounded better with better speakers. But cheap does not last & to actually think to buy one, these will be getting rare as few survive as they failed long ago.


Valve Amplifiers & Preamps: Home Made, Kit or Prototype.

The Valve-Tube world since it began in the 1920s has been a Home Constructors scene & was into the 1990s with Velleman Valve Amp kits & the Hifi News related ones. Tody the scene continues with Chinese Made ones as Plug & Play type ones. These are often no more than Kit type amps if better ones use PCBs often just copying the early designs. Our Firt Valve amp was the Stern's Mullard 3+3 later the Sterns Mullard 33RC Mono intergrated of 3w. Rectifier valve, preamp valve & output valve which was likely an ECL82 or similar. In 1961-63 adverts for £8 to £10 by Sterns so could be a hangover from the Mono era if still the type you could build into a cabinet. In the early 1990s this still worked, Aux input was a TV aerial socket type with basic EQ for 78 etc. It sounded very nice to one used to 1980s Audio, we used it with a 1939 Tannoy PA speaker in the wood case with 'Tannoy' as you see in Wartime Films. To search for that sound in other amps. But to Home Made Amps, there will be many Magazies & Forums about Making Your Own Preamp. Some may call it a Prototype but only if a Big Brand one, else it's just Home Made. One we recently saw they'd made a case & fascia. several input stages & tape output ogether with selectors. Probably built to use with the Quad II 15w power amps by the age of it. The thing is it had no Phono or Tone, these are very tricky to design right, it just had one valve per stage which could add Gain or just be a Buffer. To us it's not very useful without Phono or Tone & appears just to be made to a design in Circuit Books with little else. Actually it has a Name on the Fascia & pro labelled controls, it'll be a Kit Amp. Some like the 'Linn-Naim' idea of Flat sound, this may appeal to them, we've heard the most flat lifeless Audio Systems that the owner is delighted with. We build the 3rd Version of our own Valve Preamp based on TT ones in 2008, making Phono & adding Tone even. The thing is it could be improved now but now to try to take it apart it's too much fixed in the case, so best to leave it. It still works as we use the Phono to put Tracks onto the Computer in .wav format. Does it have any Resell value? We have the much modified TT 100w Monoblocks, again are these saleable as so Custom? Unlikely. The amps we Rebuild are done with much more thought to The Original which do sell. Other kits like Heathkit & Dynaco are High Quality Kits & these are still wanted, if like any pre 1980 hifi it can be getting too aged. The Risks of Home Made Hifi is the fact Mains may be done very sloppily & cause Live contacts inside, but so do a few Big Brand Items, Mains switches exposed & Board Links on Mains. As mentioned on earlier pages, some like the Passive Preamp, a box with selectors & Volume. These are often Priced ike they are Special with Silver Cables etc. They're just Nothing really beyond hyped, Passive Preamp has no gain, the Source my sound Sweeter but it's not the Full Voltage signal, so it's often a Case of Fooling Yourself. You can Play a Sundcard intob a Power Amp with the Computer Volume very low to start, but listening to it you hear the Soundcard noise. You need a Preamp with Gain.


Stop Asking For Free Advice...
In the last few days messages by those wanting free advice. Not just Free Advice but rare manuals & to be told how to upgrade & what to use. We just delete them, these people want everything given free without making any effort themselves. With us you either Pay for us to do the Rebuild or you go elsewhere. [1]: "Seen your website on your Akai AA-5000 can you help me im restoring this amp and have 2 transistors B170008 i would like to change all 4. Need help to equivalent transistors please. what did you intall thanks. All so the 2 caps what value did you install as im going to re-cap this unit" [2]: "Dear friends! A few months ago, information from your site helped me choose and buy a receiver JVC Nivico 5010. Many thanks. Now I use it with speakers Bang Olufsen Beovox 2400 and I like this sound.But I would like to upgrade, as you advise on the site. But nowhere can I find a service manual for JVC Nivico 5010. Could you help me and send a service manual for JVC Nivico 5010, or tell me what capacity, etc. you need to put in the power circuit to improve the sound." No Reply Required. These Messages are Insulting really, but it's how people are today, they think they need make No Effort to Learn. We worked All these Upgrades out by ourselves over several years, there are no Books on Upgrading & Most Repair Books of old are hopeless. It's a person's BTEC in Electronics plus Skill, Risk Taking, Extreme Problem Solving & Detemination that gets Results & you either pay for the job or work it out for yourselves. Or go try a Forum with Amateurs & take your chances.


To Jan 2020 Blog...