Hi-Fi Blog... Page 8 - 2024

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January 2024 Blog

Amplifier Lighting Difficulties. But There Are 8v AC LEDs Now.
LED Bulbs for some Amplifiers still Don't work Out as the LEDs Flicker Too Much. We've got some 8v AC LEDs as Blogged before coming as the DC ones on AC flicker. Is there really an AC version? For No Capacitor it's unlikely & we've bought them as 8v 29mm ones as the Car 12v ones aren't as Bright. Another Issue is even using the Original Filament Bulbs, the Spacing is too wide causing the Tuner Wondow to be lit Unevenly. They really need an LED light strip, or even Soldering a Line of the 29mm-31mm ones together. Some Receivers have more than 4 Bulbs placed "/" slanted to light better. This one needs sorting better. AC LEDS marked AC 8v 29mm' to fit the Fuse Type Filament Bulbs. Thinking in a Blog Before that this can't be right, actually it is. They've Deleloped these LED Bulbs that Don't Flicker when the typical 12v Car Mirror ones do.The Flicker can be hidden behind Tuner Windows, if the ones behind a Meter can flicker way too much. Putting the 8v AC ones in the 1970 Trio-Kenwood KR-6170 Jumbo, the brighter 8v LEDs look great, no Flicker. The KR6170 could do with more Bulbs to make the display more even behind the Tuner. Also the trouble with Old Filament Bulbs is iften they don't get the Right Ones & they are Running Too Hot which Browns the Plastic behind the Meters, Uneven Bulb Lighting? This is a Real Problem, but the Solution is Remarkably Easy. Look at Other Receivers, they have the Standard Four Bulbs yet light evenly. But their Bulbs are set further back. If you can undo the Lighting Unit, move it just 1cm further back & the Light Is Even. Hifi Bulbs Of Other Types. The Screw Type Bulb like a Torch Bulb is an 'E10' also a 'MES'. The Bayonet type Bulb like USA McIntosh amps & some Pioneer use is not one generally made, if a USA ebay seller has made some as "McIntosh LED Lamps" search will find. Whether these are Flickery ones or not is as Unknown as with the Ones we just tried, 8v AC. If there's a Market for LED Bayonet Bulbs, there'll be more made. Our 1966 Akai AA7000 needs non flickery LEDs & to keep replacing old Filament bulbs is a bore, so ours is just on 4 bulbs until LEDs are viable to buy. 10mm diameter size 'BA9S' including the bayonet lugs, varied height 20-28mm, used for Bikes may be the one? Ebay shows "BA9S" size as 6v to 120v, some LED if not seeing 8v DC ones yet. They will be Car Dashboard lights, so LEDs will be made, 6.3v, 24v, but Hifi needs 8v usually, 12v can be too dim, you can buy 10 for under £6 delivered from China, if the 12v LED 30mm ones we've found not bright enough, so decide not to try. Found some on ebay UK In Jan 2024 so bought sme to fit the Akai AA-7000 & Pioneer SX-2500. These were the clear lens ones with the typical LED Anode & Cathode. They look nice so worth a try. Trouble is they are just a thin area 'spotlight beam' light that leaves a 1cm circle as lit but the rest dark, so what use they actually are to ayone is a bit of a mystery. They don't flicker much is the only good thing. Described as 'Wide Angle Beam' which they clearly aren't so return them. USA seller has similar ones with a clouded lens for McIntosh & they had them custom made. These are way expensive to import & who's to say they'll be any better. the 'spotlight' ones we put Tape on & it didn't diffuse the light much at all. Cluster LED 'BA9S' Bulbs. These are another option, these have use in Cars which seems to be the Market developing small LED bulbs. These Cluster ones have a LED element on the top edge & a run of them around the body of the Bulb. To suspect the top LED will be bright & the rest a lesser light means it's not worth trying these. Bayonet has to stay old Filament bulbs still & not worth altering to different bulbs as you don't know what will turn up next. More BA9S LEDs on the Farnell site, including one with a 5mm LED inside a BA9S case with it showing inside. At £9.00 each they are just not a good one to even try, we need 12 of them over 2 amps, £108 the lot, er, no.

The Forgotten 'Silver' In The Hi-Fi Components Range.
Silvered Mica Capacitors of low values are a Forgotten thing in the New World of Ceramic Surface Mount Capacitors. Fizzy Ceramics have No Place in Hifi but they are used excessively, the Top USA brand McIntosh surprisingly uses them even in the Tone stage, the Treble is on a Ceramic Capacitor which is pathetic, but typical for the early USA amps with UK-EU parts not even the Film ones Japanese Amps can use. some do use the 'Silvered Mica' as Sony do with the small square ones. You can still buy these & one ebay seller has plenty if the 100pf & 220pf ones are long gone. Why Use Them? The Film Capacitor much used is still way better than the Ceramic, the Polystyrene ones used to be much Craved 20-30 years ago if the Silvered Mica has largely been forgotten. Getting some for the 1973 JVC 4VN-990 to just try them. We've used Silvered Mica on other amps & the Silvered Mica vs Polystyrene-Film Capacitor can be a huge difference, but only if the rest of the Amp is worthy of the 'Fine Silver'. The Sound in certain uses can have a little slurry compression with the Plastic Film capacitors, if the Silvered Mica is far more true & has none of that. Imagine a Tuner with all Silvered Mica instead of the crappy Ceramics, we did a Sony STR-6120 & the Trio WX-400-U with all Film capacitors to get a much sweeter Tuner sound, perhaps the Silvered Mica would be overkill. These are Expensive items, in terms of other capacitors of the value, well worth it if they are really needed. So looking on Farnell a 100pf one is a USA-stocked item £2.50 to £5 each, plus the £15 delivery. RS Radio Spares has none so they are 'Gone' items as are Germanium, Transistors. Did buy a 100pf for a Trio-Kenwood TK-140X a few years back when they were still around. Explains why the ebay guy who says he's stashed these for years collecting them, a wise collection when they were unwanted, a light clean of the dulled 50+ year old wires & they're fine. These are Top Quality components if limited in use for unavailability & the fact most Hifi isn't revealing enough to understand the need for them. What Did The JVC 4VN-990 Sound Like With Them? This is a much upgraded amp with lots of redesign, yet it still Hums if SEA is turned up more on the middle three. Therefore it'll be the one for trying ideas. The Treble is just Cleaner, with none of that slight compression a Film Capacitor can have. It makes Stereo wider. It's Sweet Treble Sound which is very hard to get, but it's what your Amp full of Zener Diodes & Limiting hides. Not many amps can upgrade this good as it's often too difficult to try these ideas. Silvered Micas are the final upgrade. They'll make no difference in a Stock 1976 Pioneer SX-850 for example.

Sellers Of Aged Vintage Hi-Fi: How Honest Are They?
To ask Sellers Questions gives you a good idea of what you're getting. Years Back, a Seller would say 'In Working Order' yet the amp or receiver is way past it's best. One with a nice Receiver we have the Amp version of & know it's problems. To find one for sale with a bad Tuner means their price is way too high, if the Tuner worked the price is reasonable if still high. But to get a bad Tuner is not an amp to bother with as the odds are It'll Never Work, the 'hope' it something simple is never the case. Sellers Play Fairer, they say the amp works but has issues. To cover themselves they put 'For Parts or Not Working', this & the description tells it's not perfect if is probably a lot more tired. You'll find some USA sellers doing this even if they've Recapped the item, to stop the ebay games that stopped us selling Serviced Gear over 10 years ago. For the Seller, the item is sold as Described & you can easily see it's not an amp for a General buyer, 50 year old amps need work & not just playing until it fails 1 week or 1 year later. Having kept some as original until they start to fail, a 1970 Sony STR-6120 & a 1966 Pioneer SX-1000-TA lasted for some use over a year, but not much more. The seller saying a bad tuner doesn't put buyers off is hoping you're gullible, why buy a receiver with no FM, AM by itself is of no use for the lo-fi sound & in UK only Talk Stations use it. To be then told 'amps of that age need a rebuild' is undermining you too, that wasn't in your advert. Like Anything, want it bad enough, buy it, but if it has a fault that means it'll not be fully working, leave it be unless fairly priced. Even Recapped Receivers with no FM Tuner we've had to sell off cheaper, they are still wanted, but the price isn't what a fully working one can be.

Problems With Amplifiers & Receivers When Buying Or Selling.
As we'd rebuild any Amp we'd buy, for it to Work or Not isn't so Important because of the Age of ones we go for, as in 1965-73, just 8 years in the History of Hifi. We'd like there to be good ones after 1974 into the 1990s, if they are generally Too Expensive, Not Findable or with 'Unwanted' things like ICs. Condition Matters, to rebuild a rough amp means you end up with a Rebult but Rough Amp. To forgive certain inevitable things like Fascia Print worn off as it's only flat printed, not Embossed, the KR-6200 lost some print on the Push Buttons part if the KR-5200 spares amp had a good one. Little things may bother you or not, for the Age to accept certain things & you may find a Parted-Out one on ebay USA. Missing or Broken Parts put us off unless we have the part to fix it, or can buy a spares one, as with the KR-6200 mentioned in Blogs above, who has the Speaker Connector part? Seeing a Harman-Kardon receiver, 20w worth having but one of the Control Knobs was not the right one. H-K 330C has a plain control knob, but to find even their 1990s one will have been hard, to find one that matches size is down to finding a spare. But it had no FM tuner working so not for us. No Tuner Working puts off those who use a Tuner, we know of only one who does Tuner work & by the nature of it, it's an expensive job. In the UK, there's not much on FM these days, the Digital Radio & TV sources have far more. A lot of FM is compressed still making FM not as 'Hifi' as the Digital Stations. Prices On Selling Ones With Problems. As with anything, first offer at a certain price, but find ones sit so to reduce. The Dead Tuner is the biggest downprice, Damage can be Repaired, if to buy carefully aware of it, such as Pioneer & Yamaha with top edge damage on the fascia. Missing correct Control Parts is one we've not tried as to not buy one like that, the 'wrong' bit hits the eye. Buying Raw Aged Amps is what the Vintage Hifi scene on ebay is, many still buy & just plug in to use. To wonder how many go bad soon after & trash a good pair of speakers is one you don't hear about. In the Car World, you hear of Vintage Cars always Breaking Down, the BBC 'Antiques Road Trip' often swaps cars as the ones they get can't be quickly fixed. Look closely at them, they are User Cars, not Collector Restored ones & the faults are what the Big Rebuilds can sort, much like with Hifi. What Hurts with Post 1980 Hifi is that it Can't Be Fixed as Unavailable Parts or into the IC world of Multichannel AV amps. People try to get them fixed, no Tech aware of them would want to get involved as failure is high. See these AV amps on ebay for £40 with 'error codes', some might be repairable if you had 2-3 amps like we did with the 1977 B&O Beomaster 1900, but the odds of all you had having the same fault can be high. With Modern Gear, if you got 10 years use, well done. To get 20-30 years use does happen, but you bought New so go buy New again. Sad to see Big Money stuff be 'unrepairable', go try the Manufacturer if they are still around, some of these Small Companies had No Service Depts even when new. In the late 1960s the Japanese brands only listed a Japan address, this caused owners problems, but they soon wised up to get a UK Distributor. See 1966 Pioneer & Sansui with no UK base in their adverts.

Pioneer in Hi-Fi News Magazine From January 1967.
In keeping with how unthinking people today can be, right hand not knowing what the left is doing, Pioneer were doing this in Jan 1967 years before they threw the brand to 'Comet' to hugely discount them. An Apr 2023 blog above found the brand sort of fizzled away in the Hi-fi News mag if were still advertised as 'Pioneer'. These ads covered the Valve Receivers more. But we're reading through the 1963-1969 years for the third time & it's bringing up new things. Jan 1967 shows the Hifi Market is a lot more advanced to 2 years before, the amount of adverts grows a lot, often the same ones month after month must have bored readers. But p873 shows an amp we've recently got, the 1965 Pioneer SX-600T, a Germaniums Receiver, or Tuner Amplifier as they were called then. Poke in the eye to see our amp being advertised in a UK magazine. They don't say it's Germaniums & only 'Transistor Protection' by a top mounted device in ours is the only mention. So why didn't we see that before? UK now Sole Distributors by 'Swisstone' of Surrey. "It Sounds Right - It Is Right" is their selling line header. Too right it is, a very crisp accurate sounding amp if a little tamed to keep the Germanium Hiss down, if not quite having enough gain. One we'll keep with to hopefully better it, recapped already. Their ad says "Dealers sell it to themselves at their first demonstration" as the sound is clearly way ahead of other 1965-66 sold Hifi & generally was never heard this fresh sounding again once cost cutting & limiting became normal. So to blog on what Swisstone-era Pioneer had to offer before Shriro took the UK distribution over later. Jan 1967. Pioneer SX-600T full page 'ear' ad. Feb 1967 same if half a page for the main ad part. Mar 1967 full page 'ear' ad with the many shops stocking Pioneer, Swisstone clearly making a big effort here, 23 shops including London's 'Harrods'. Apr 1967 the same Feb one for the SX-600T, clearly Sales weren't there as this is a Rare amp to find. May 1967 the full page Jan ad, clearly they planned adverts & bought ad space in advance. Jun 1967 the 600T half page ad again. July-Oct 1967 no ad shows they bought 6 months of space, when the SX-1000-TA was around plus the SX-1000TDF & SX-1500TDF would maybe be new ones. Nov 1967 they return with the Pioneer SX-300T (not TA, TD etc) which is only 12w, aiming at the lower power market, looks like the SX-1000TA with the small lever switches if has a control either side of the Tuner glass. But looking at the manual on HFE, it's still a Germaniums amp, a 1965-66 leftover as Silicon was the deal by 1966. The looks are 1966, a design would be started quite in advance of release. Never seen one. Dec 1967 has the Jan ad with the 300T instead. Jan 1968 same. Feb 1968 none. Apr-May 1968 same as Dec 1967. This seems that Swisstone just bought out the now-obsolete early SX-600T & SX-300T only, an early example of Japanese brands clearing out old stock, like others did in 1971 like Duette & the early Rotel. June 1968 end of series. By Nov 1968 Shriro (UK) had been with Audio Technica & introduces Lucman (as Lux oddly) with the HQ-555 amp, By Mar 1969 Shriro (UK) have the Luxman (Lux) SQ1220. Aug 1969 Swisstone return, oddly still with the Germaniums SX-300T but adding new models SA-500 & SX-440 low powered 13w amp & 12w receiver of black fascia stylish looks. Oct 1969 Swisstone finally ditch the 1965 SX-300T & full page ad which also has headphones SE 30/SE 2P, tuner TX 500, turntable PL11 & speakers CS 52T. Dec 1969 has Shriro (UK) taking over as Pioneer SX-1500TD the later styled one, if it's listed as 'Pioneer' in the ads index.

1970-71 Pioneer SX-9000 & 1970-71 Pioneer SX-6000 Receiver.
We last looked briefly at this on the Dec 2019 blog with the SX-2500 we since got & another obscure SX-6000. To be messaged about this to see HFE has the other manual with the Circuits, not just the board layouts gets this one worth a look. From 1970-71, info not too precise on year. Both are Capacitor Coupled designs. The SX-6000 is a 36w receiver of 13kg, if silly hyped ratings call it a 200w one, IHF 200w at 4 ohms, but not in our world, that's just pointless peak power x 2 channels USA rating. We see it as a 40w receiver. Works on 76v HT, a standard receiver design unlike the SX-9000. FETs tuner, ICs on tuner as typical. Power amp has the Output Transistors on the PCB like 1969 Pioneer SX-1500TF, not the 1967 TDF. It has the Output Capacitors on the PCB too which isn't great. SX-6000 is much like the SX-1500TF, Pioneer did make several similar models in the era when Tuner Design changed often, if the Audio Stages didn't. Would expect it to be a decent amp, if rare for how Similar other models were. The SX-9000 is a proper 50w receiver of 16kg weight. In the 1972 HFYB for £289. In the style of the SX-6000 with fascia changes from the 1969 styling. This amp has Extra Features as does the 1971 Trio-Kenwood KR-6170 Jumbo, this has the Reverb & a mysterious 'Pre Set Tone Colours' which the KR-6170 has too, ie Jazz, Vocal preset 'EQ' settings. Has two Headphone sockets, if why two people with an amp would use Headphones, not share on Speakers. Many controls & inputs behind a fascia flap that would usually be open so why bother with a flap? 'Tone Colour' switching like the KR-6170, the 'Reverb' here is an Electronic one on Transistors, no long spring box. A streamlined design of the 1969 Pioneer SX-2500 if before the Differential era of the Pioneer SX-828. Having both 'Extras' on the Trio-Kenwood KR-6170, how useful are they is up to you to decide. Both look the quality of Pioneer designs of the era.

The Repair Shop Shows It's Weakness Now: Lack Of Good Stuff To Repair.
A June 2023 episode mentioning 'The Windrush Generation' clearly shows this. To say we find it 'Rather Patronising' is generally how the BBC treat certain folks. 'The Antiques Roadshow' clearly hires in certain people to be at the front in the Audience & shows certain segments from older shows to 'keep up the quota' which is beyond Patronising yet it's accepted by those not realising the BBC is playing silly games including even having The Owners being Actors, USA 'Pawn Stars' does this too. Say no more... The Repair Shop S12 E7 is this episode. To remember these folks back in the 1980s to see there were good people made us wonder why others had other opinions, even seeing 1980s 'The Bill' with other New Folks to see how they were treated to ask one older why as similarly seeing they were good too. To know these folks to like their Music as our Record Sales show our interest. Gently written as Today won't let you 'say those things' but the BBC is seriously taking advantage. Back to the show, nice stories on all four items, avoiding the misery of usual shows, upbeat hopeful stories plus old wedding photos the BBC could make a big fascinating series on, but they don't want to go that far. Show has some strange items. To see they have no monetary value if are sentimental things, not sure how a worn if acceptavle grade cardboard Suitcase is considered worthy that she has to re-line losing much originality, rather than just leave alone. It gets tidied if surely not for Airplane use as it'd be wrecked. Then a water soaked Passport he does a tidy job & is more worthwhile perhaps, if an odd thing to restore. A tired plain 1960s wood case mantle Clock that we laughed at, tons of these at boot fairs unselling for £1 likely & the clock guy must treat it like it's a Georgian Bracket clock. Better innards than just a battery one. The stained wood on this clock wouldn't bleach as they say, but taking a TV photo of it done & looking nicer than you'd think, it is the same clock, veneer painting will have tidied it. A clock in front of our TV is a 1950s green bakelite one as 'retro' as this, the high grade really makes these clocks. Then to make it 'Blog Worthy' yet another Radiogram appears. These have been on several times, always the budget brand ones, if imagine the pleasure they brought in the day & surprising to see they were kept. In the 1980s a Radiogram in our shop was put for sale, eventually selling after ages, or if damaged or not working it got binned. This was the sad era where older wind-up players were ripped out to sell the cases to those who think it'd make a good cabinet, which they never did & never sold. The Radiogram owned, or bought for the show. He says he's never heard it it was given by another person & it looks better condition than 40 years in a damp garage. They say he's an OBE guy responsible for making 22 June 'Windrush Day'. He starts off too political so not wanting to hear that if the idea of a day in a month when the whole month is another thing is a nice idea, if who's heard of it? Around a 1960 era Valve Radiogram with those horrible autochangers, a 'Monarch' one, Radiogram name shown but can't read it. These sort of small models generally bought by a woman owner who rarely used it. The bigger radiograms more used for Partying as more solidly made, rather than the thin legged thing that'd easily get knocked over. All cleaned up it looked smart, if not one to play Valuable 45s on, they have an appeal if generally a Collector would want a Higher model, the only radiogram we have is that 1932 Pye G/GR. We had perhaps the most stylish & pricy Murphy A138R 1949 radiogram once, edging towards hifi with Push-Pull PEN 44 outputs.

February 2024 Blog

1966 Pioneer SX-1000TA Receiver.
This is the First in the 'Smaller Case' range after the SX-600T & SX-1000T if before the SX-300T. Short-lived version as Tuners changed a lot in this era & only One Speaker Set became outdated. We've had this a while, if never done anything beyond a service as despite the age it still was useable. The one that needed a proper volume control & loudness as some vandal put a small 1980s PCB type one in & cut the loudness. Parts amp really, the sprayed top lid with dents not very nce. But we have thefailed SX-1000TDF that has helped a few other Pioneers now & as we recapped it 'hoping' it'd work as Like New inside, it never did. A Reject amp that had 'nothing wrong' but nothing would stop it ruining 1 channel. Collection of Bits to reuse & the TA & TDF are much the same, if to use the TA with the parts. The Nuvistors Tuner Front End uses an Axial cap underneath & then a Single Can with Two 100 150v stages. 140v for the Valve 6HA5 & 100v for the two Nuvistors 6CW4. The other boards Power Supply, Phono, Tone-Pre & Power Amp are much the same as the SX-1000TDF with the odd change, using better transistors as before the 2SC458 hissy ones. 2SC369 & 2SC283. 2SB421 in the Power Amp is a PNP Germanium as a P-P Driver, the rest are Silicon in the Audio Stages. The SX-1000TDF designs it differently on Bias. A strange bit of design on the Power Amp first transistor is used in other Pioneer like the later SX-1000TW, why does a transistor need a Voltage on the Emitter? Some sort of Protection circuit? Has that 'PTF' board in the corner underneath that is a 'T' Bass Filter, first seen on the 1965 Sony TA-1120. Why scared of Bass? These are strong amps to cope, but the tedious Buyers with cheap Rumbly Turntables complained. What does 'PTF' mean... 'Pioneer T Filter'. After the SX-600T & SX-1000T the SX-1000TA is a Capacitor Coupled amp rather than the 600T Direct Coupled & Germanium amp, the 1000T no manual found as another short-lived model if we've got a printed once since. Decided to sell the SX-1000TA for having the SX-600T. The SX-1000TA has a great fresh sounding tuner, the Valve & Nuvistors have the Best Tuner sound.

Zener Diodes Are Lazy Design But They Are Used By Default.
These are called 'Reference Diodes' in a way to seem a good idea, creating a stable voltage in a Power Supply. But they are used to cover Lazy Design when a Resistor or Regulator can do the same thing. Perhaps it takes a few seconds longer, which makes little difference when you see how long the Required Voltage takes to arrive in a Regulated power supply. The Zener holds the Voltage at a Set Voltage, such as a 1970s 'WZ130' is a 13v one. They are used directly on the Required Voltage or as part of a Dual Transistor design. Looking on Wikipedia for a deeper 'why', they are 'Doped' to sit at their required voltage. Like a Dog tied to a post by a lash, it can only go so far & annoy the Dog as it's movements are limited. The Zener regulates the voltage down, in a similar way Quad do with a 'Current Dumping' amplifier. The Zener therefore Wastes the Power under the misleading idea it is like a Regulator. On one amp to read the voltages without the Zener it sat steady on the voltage & charged up fast, so why was it needed? To stop someone having to think how to bypass it. The first Audio item we saw with a Zener was the 1970 Hacker GAR 500 in 2012 with one on the Preamp-Inputs board, it took the 36v the Power Amp used & pulled it down to 22v, what's the point of that? To be able to use 25v capacitors not 50v ones is probably why, save a few pence. Beware some earlier Diodes are 'hidden' as Zener Diodes, lacking the >Z zener diagram. Some amps are designed better with their Zeners & regular Diodes. To think of designing without Diodes is a risky one, you'll bring up crazy noises & give instability.

Why Has A Modern Item From 1999 Still Got Stupid Weaknesses That Were Solved Decades Before?
Watching 'Wheeler Dealers' S16 E11 the 'BMW Z3M Coupe'. Not sure why Discovery never showed this series fully, seeing lots of episodes for the first time. Very Nice Car from 1999, probably one of The Last Proper Cars before the Generic looks that were around even then. But it's got Rubbish Design that Ant has to sort by adding thicker metal to a Rear Wheel Drive that was too strong an engine for the Bodywork & Chassis. Heard of this before on 1970s Cars, but a 1999 one, surely all the weaknesses should have been perfected long ago, a rubbish front fan taken out as a poor design. Of course the TV Show is well researched & many minds go into 'Upgrading' these cars that are mostly great with a few weaknesses. In Hifi. You may be surprised to find Transistor Amps were nearly Perfect by as early as 1965 with the Sony TA-1120, Sansui TR-707A & Pioneer SX-600T. To find a 2007 Marantz PM 6002 one removing 100 lots of dumbing down, was really no different to a 1977 Yamaha CR-2020 in design. Dumbed down to give better S:N ratio, adding in Remote Control items with the next range having a DAC input. These 1965 amps were The First Proper Transistor Amps, the Sony all Silicon, the other two mostly Germanium beyond the late stages. In Cars Again to see shows like 'Counts Customs' putting an impressive 'Corvette LS3' Crate Engine with all the extras, cost $9250. Their customers. mostly those over 60, like the old cars but the limited, aged & weedy original engines are just not use-daily enough. What's In Hifi? Only Upgrades can make your Vintage Hifi better. It's a Dark Art & there is No One doing this beyond us. Many recap like-for-like to get an overbright amp, limited by the original design already & see them sold on as the owner expected better. It's Why We Upgrade as Better Is Possible. The deeper we get into looking at design, to be so tired of seeing rubbish design that holds back an otherwise great amp.

Is There An External Relay Box With Protection?
Certain Direct Coupled Amps don't have a Relay & are the later Differential design without the Output Capacitors. Knowing Relay Amps from adjusting many, the Relay has a sensing circuit to cut off the Relay once over 1v DC is read. This is quite high, when 100mV on Speaker Outputs on some amps is the best you can adjust to with that seeming quite high, so have it User Adjustable. Is there anything like that? The nearest we could find is a B&O relay box if it only seems to switch between main or remote speaker sets. There Is Nothing. Something that should be easy enough to invent, based on Relays in Amps since the early 1970s, why has this not been thought of? The Vintage Market could use such an item, from those not wanting to risk exoensive speakers to the lazy sort who plug in a 50 year old amp without even servicing or even checking it. How many speakers get ruined using aged Amps of any sort? Output Capacitors age & so do Relay Circuits. To have your Own Safety Relay for Speakers is surely one to invent. Idea (c) select45rpm 09/06/2023.

Is British Hi-Fi An Outdated Joke By 1967?
Yes it is. The British were all too willing to Rest On Their Laurels, without taking notice of how other Markets were progressing. We have a USA Hifi Book-Magazine from 1960, it is quite surprising how ahead they were that early, if a lot of New York schlick in selling with the Salesman more choosing what you'd buy than anyone else. But they had good stuff to sell & a 1960 British buyer would have been comparing to what British Hifi was & pitying the fact it was all 110v only in those days. HFN by 1965 has non UK buyers not liking the Crude UK Casework when just look at Fisher, Trio & Pioneer with smart looks. Onto 1967. The Japanese market was getting established with UK Distributors & the brands like Pioneer, Akai, Sansui, Sony & Trio were ell known from their adverts, if not all known for Receivers & Amplifiers yet. Not all brands imported theirs yet, the Tape Machines were of more interest. There was reluctance with Japanese products in the USA for obvious War reasons, if the sheer Quality of what Japan was making, taking USA & EU ideas & improving them. HFN magazine ads for Japanese brands pre 1967 often only showed the Japan address & relied on Main London dealers like Imhofs to import these. 1966 adverts are still the same Quad, Leak, Rogers, Bryan, Tripletone brands, to see B&O start to get stocked for the '900' series Radio that was with or without speakers & a radiogram version. In earlier years Blaupunkt & Grundig radiograms were popular, if they never really went to Hifi Seperates in the same way. Leak had already made restyled Tuners & Amps for the USA market that looked far smarter than the UK models. Quad in 1967 were still selling the 1953 Quad II amps, 1958 Quad 22 stereo preamps & the 1957 Quad ELS57 electrostatic. Peter Walker was considered a 'Hifi God' by the Hfifi Press, clearly some bias with Quad ads always before the Editorial-Index page, always in the Hifi Yearbook front cover into the mid 1970s & the amount of articles about Quad. But in reality, to read that Shops only stocked those old fashioned amps to get the ESL57 is a case of Peter Walker not listening to the Market. To be fair, he was 61 in 1967 & him & Harold Leak both brought a lot to Hifi, if they were not at an age to take fresh steps in Hifi. Leak made the 'Stereo 30' amp in late 1963 so he was probably the same age. 'We Like Quad'. We don't particularly, their Transistor gear in our 1963-80 era isn't to our taste & we've not bothered buying any, reviews on the 'Other Amps' tell why. The ones who claim to are 'Davis & Kays' of London, with a slightly insincere Mar 1967 HFN ad picturing these 'ancient' 1950s items in a 1967 ad. They say that many newer amplifiers have moved on but reckon the Valve-ESL set up still can compete with the more modern USA & Japanese gear. Not so, the Quad were still only 15w & the awful clunky preamp could only be used built into a cabinet as it is too light to push buttons without it sliding away. "'We think that Quad can still compete with the best." Not 'know', just 'think' doesn't sound too convincing, with your Dad's era Hifi still being offered to the 1967 Hipsters, it's way out of date. But as the Quad 44/405 show, people still buy these first transistor models into 1980 as they are still available, probably old stock unsold in the later years. Looking at the ad, Quad II & 22 were priced at £50 the pair, when more modern valve gear is £31 & £42 as the Rogers Cadet III & HG88 III are & better value overall. Japanese Hifi Soon Led The Way. Not hard to see why. USA gear was limited to Fisher & Sherwood from ads of then. The abolition of Retail Price Management-Maintenance since 1964 can only be good for Hifi was the idea in HFN, if to son see 'Comet' exploiting this & heavily discounting. To see Pioneer were very discounted to the point they had to further cost cut to make a profit & survive. This opened up the Hifi world to Overseas sellers, firstly with Open-Reel Tape Machines, expensive items if how many sold to the small audience for these? Then came FM Multiplex Stereo, the Japanese amps were wise to make the Stereo Decoder an integral part of the design as our Trio WX-400U shows. Pioneer pre Multiplex era had strange dual Tuner ideas to tune into Stereo via separate Tuners, one on FM & the other half of the Stereo on AM. The Build Quality & Styling set Japanese Hifi apart, look at the USA styled Trio WX-400U again to show. By 1967 Silicon Transistors were the usual way if in 1965 Germaniums were the main Transistors. By 1969 Japanese Hifi was onto a Second Generation with many High Quality Amplifiers & Receivers, sort of leaving UK efforts looking so old fashioned. By 1971 Leak & Fisher had sold out to other companies & the small UK brands had just about finished.

By 1967, UK Is Still Slow Getting The Non-UK Brands Of Amplifiers & Receivers.
Reading the adverts in HFN, Tape Machines seem to be the first non-UK items offered in the UK, with Akai & Sony being the most frequent advertisers & Sony having a London shop by 1966. Other 'Continental' brands are much around too with some still rather old fashioned suitcase type designs, when Akai & Sony are offering more modern casework. The first Japanese brands advertised for Amps & Receivers are Trio_Kenwood, Pioneer & the budget 'Eagle' brand who only started to do better gear by the late 1970s, still midprice quality. Both Sony & Akai have Amplifiers & Receivers, the Akai AA-5000(S) has to be a 1965 design & the Akai AA-7000 is a 1966 one. Sony have the TA-1120 & less well known TA-1080, but there is no mention of these beyond the Akai getting a brief mention from European Audio Fairs. April 1967 Audio Fair article in the HFM magazine says Akai are introducing their two at the fair AA-7000 said 'all silicon' & AA-5000 said "fully transistorised' as it's part Germaniums. Sansui had already arrived by 1966 if not showing UK Distributors will have meant few sales from special orders, if Sansui sold well in the 'Army & Navy' military stores to be exported by the buyers. Sony isn't mentioned yet for the TA-1120 if a review later in 1967 suggests this is now the TA-1120A meaning the first TA-1120 wasn't sold in the UK, unless you ordered one specially. Continental-European brands like B&O, Arena & others, if still other brands weren't represented. Does this give the idea that The English were not a good market to sell to, still stuck with their Quad Ancient Valve Gear, the Quad 33/303 not arriving until 1968. Looking for ceetain vintage hifi, you'll find it more in the USA & Germany than the UK, with certain hifi only sold off cheaply once the stock was outdated. The brand 'Sanyo' is well known in Eastern Europe as this is where the brand was sold to when other countries weren't interested, selling off 5-6 year old stock at bargain prices. We hear of 1980-81 certain places worldwide selling the 1978 Yamaha CR-2020 off cheaply as by then the market had much changed & a CR-2020 was seen as just goods to clear & seeing one invoice they got them very cheaply.

March 2024 Blog

Why Are So Many Decent Quality Amps Parted Out?
You see on USA ebay mostly that a lot of good amps are parted out. This is great if you have an amp or receiver lacking a part that devalues it or makes it a parts amp too. The parts you see suggest the sellers are not really trying to get the amps sellable by repairing or rebuilding. The Car & Motorbike scene seems to have an endless supply of 'Rare Parts' that aren't so rare if you search around online or at markets or yearly gatherings. Hifi is growing more for people seeing The Quality in Vintage & we know we'be played a Huge Part in the game as have info sites like HFE as without manuals, any hifi work is much harder. Parts like fascias, control knob & switch covers will readily sell as will a top lid as this covers loss & damages. Internal parts like tuner glasses may not sell as they never break, we parted a Sony STR-6120 & no takers for the glass or transformer, if the MPX Tuner part with the relay sold the fastest. It Reveals How Few Decent Restorers & Repairers There Are. To find a nice power amp board for a rare Sony was unexpected, our one was burnt on a few parts meaning it'd need too much done on a board less tech-friendly. But the amp it came from will have worked, what was wrong with it? It could have had no top lid or base like a Trio-Kenwood KR-5200 we bought for £30 for the parts, it recently fixed our KR-6200 speaker connectors & the output transistors got use already to keep a matched set. A set of 4x NPN or a set of 4x NPN-PNP TO3 output transistors, buying from trusted online sellers, not ebay, will cost you £30 a set these days. To see a picture from a Vietnam owner with McIntosh C26 & MC2125 pre & power recently, these were covered in spider webs & dust, but with the fronts to the wall. These amps probably have bad glass fronts or none, these you used to still be able to buy from McIntosh in 2002 when we had our Macs & Panloc cases. You could buy Repro wood cases then too. But today these in average grade are probably only good for Parts else they'd have been fixed up & sold 10 years ago by the amount of 'age' on them. Some Amps Don't Repair Well. Badly Designed not to be Repairable without totally taking to pieces & the thin track that comes loose once soldered, even just unsoldering once. Those who think they are doing good by keeping track too hot whilst they remove all old solder will leave loose track. If the track is alreay fine with smaller later transistors, it leaves loose track that won't be reliable enough to sell so the amp is of no use. The Realities pof Later Hifi: It's just Not Repairable. We Part Out Amplifiers. Some amps you can sell parts, if ones we can't sell get the parts kept & they do become useful. The 1967 Pioneer SX-1000TDF that looked like new inside but we could never get working has helped a few other Pioneer now to have their damaged parts renewed. This amp was a bad buy, but at £60 the parts used made it a Bargain in retrospect. We Buy Amps Sold As 'Parts Or Not Working'. Some don't need much to work, as we are the Hifi Techs & this is our game. Why pay the overpriced 'working' prices for an aged amp that'll be rebuild anyway, taking in Repairs & Service. To see a dreamer asking £800-£1000 for a 'working' one yet to see the 'Parts' ones selling for £200 or less is how we like it. We can Gamble & it doesn't always work out, bad repairs or bad messing are the main reasons why we see an amp is unsellable. Having a cache of parts & good problem solving means we can sort tricky issues & for the USA ebay sellers parting amps, rare bits can be found. To 'cobble together' the many missing fascia parts on a Yamaha CA-1000 took a while, to get the unfindable Bass Control Pot that only this model uses, a L+R adustable one was found by a seller who parted everything saying the transformer was bad. Knowing the amp, we can tell it wasn't, but they lacked the skills & knowledge to fix it, so they unsoldered the lever switch inside parts that will never fail, unless you break the end tip bit off. Some Amps Are Worth More As Parts. Very few, only the popular ones, as in the STR-6120 we parted in 2011, one we got maybe in 2002. The fascia, control knobs & switches, tuner parts all readily sold to the point our £10 amp buy netted about £300 in total. This got us buying a working STR-6120 from Canada in 2012, the days before prices & importing got expensive. But try to part out a rare amp that's 'unknown' or not a wanted model & the parts won't sell.

What Is Vintage Hi-Fi Actually Worth?
Beyond the unhelpful "It's Worth What You Can Get For It" or "It's Worth What Someone Will Pay", to see what items actually sell for. You can see on Hifi Shark site what overpriced amounts some hope for, as with ebay, if both have "Sold" listings to see what they actually sell for. Beware Of Some Sellers on ebay listing items "That Get Sold" yet mysteriously get relisted soon after, with some lame excuse why, or none. This is Shill Bidding-Buying to create a False Price Status & for the buyer to research, or end up way overpaying. We are supposed to believe the moneyed buyers just buy on a whim rather than buy intelligently, after all how did they make their money in the first place? TV does play it dumb, like the paused then big bidding on 'Auction Kings' TV show, it's just scripted fakeness. Beware Of Silly Overpricing. We sell our Rebuilt, Recapped & Upgraded Use Daily Hifi at certain prices, often Our Price doesn't reflect the Work done to get it to that standard, plus the Loss Element of amps that aren't good enough so get parted, as the Blog above tells. To see the 1973 Yamaha CA-1000 amplifier listed for years on ebay at high prices is so unrealistic. The rebuild job in the amp would cost you that, yet to sell our Rebuilt one, that's what we got for it, having sold plenty of rebuilt Hifi. The Marantz overpricing, having had the big 185w Marantz 2385 to buy at what seemed a good price plus the original lid, to do a big rebuild job but the Resell Price wasn't what we hoped. It was worth trying such an item, but the sell price was far from what it'd cost for a customer rebuild as a lot in it to do. What They're Worth. There are certain amps that make more Money than the Amp itself is worth, the designs aren't quite the "Prestige" the Brand seems to hold, first found this with Bang & Olufsen 1969-77 Beomasters. More modern "Audiophile" amps, a term used by the Hifi press to get sales on these later amps we don't have much interest in, can make high prices, lots of high prices on ebay with very high RRP prices. RRP is of no value to know, see how far they'll Discount the Ex-Demo ones, our TT power amps once £4700 in 1995 if Ex-Demo price as they wanted rid after they'd gone round all their branches was around £1200 with them readily heavily discounting the 2 box pre & the Phono pre as they found "some sucker" to buy them. You can still buy good but tired & often not working Amps & Receivers for £50-£100 even today as we've had some bargains. Some can overprice a bit, but seeing one you want, the game of get a bargain or pay up more balances out. To get one you wanted brings pleasure after all. Enough has been said about how Aged these items are, to get a 1969 amplifier that "works" but has hum & crackles is you being sold to unfairly, if on the other hand an experienced buyer should expect to be not told the truth. At £200, so what, it was a good buy, on a £600 buy then you should expect a more honest deal, but that's a little naive to expect. One seller with a 4ch Receiver we'd like is cheeky to say 'if you want it pay up' yet his Tuner doesn't work & no mention of anything 4ch related working or anything about anything actually working. We messaged them once to hear more, to be told it's so old it needs a rebuild anyway & collectors aren't bothered by dead Tuners is for you to consider, laugh at or wisely run a mile. What They're Worth To You is another thing. For the age of Vintage Hifi now, to find good amps being rescued from attics, clearances, recycling yards & damp sheds, to take a certain amount of 'tatty' if it can be tidied to look acceptable in someone's lounge, as that's where it'll go. Is it worth paying £100 for a tatty one when a better one is £200 if it's in USA or EU & will cost Shipping & Import Charges. If the tatty one can be made nice & you have the missing bits for it then that's the decider. To then see other ones offered at £600 as raw original, then where is the real price? Generally £200-£300 will get a good 'Project' amp. Hyped Prices show themselves up, we looked at a Luxman 1979 CL-32 or CL-34 valve preamp a few years back before deciding to just sell the power amps. To see those same high priced preamps still sat on ebay. Luxman again, to see the early Valve Amps priced up way high for original 1960s ones, again they never sell, buyers are generally cautious of Valve Amps for the Rebuild costs. Be aware Hifi getting sold to a Newbie & they realise it's way out of their Depth & sell it on to cut their losses.

Abandoned Goods Left For Repair, What To Do?
The Way We Do It is not for this to happen to Us. To say only send amps if you're ready to pay, plus offering a Full Paper Trail with Tracked Courier Delivery & Collection, not the 'blind trust' way of Doorstep Drop-offs as some will still trust to a residential address, not a Street Shop. To pay by Bank Transfer, not Paypal Gift unless you are known gives further assurance as these Proofs of Courier Tracking & Bank Payments cannot be denied. But What Actually Is The Deal If Goods Are Abandoned? TV & Audio-Hifi Repair shops of old were forever stuck with Abandoned goods. Hifi we've had showed labels saying items were 'Too Far Gone' or just abandoned. This takes up space in a shop & you'll have seen piles of 'dead' goods that the TV Repair Shop had to keep. If the customer gave a Written message of abandonment or signed a Receipt similarly, the Status of the item would be confirmed, as in for the shop to become the owner to sell, repair or break for parts. Without this, the person could turn up years later & demand the item back as legally it was still theirs. The Statute Of Limitations might apply. But to Google this as of typing, the only requirement is the person who still owns the item is told to remove it or it will be Disposed Of "Within A Reasonable Time". We had this long ago, left with a several-hundred pound job on an amp, but the owner now couldn't afford it. An experience leads to Terms made. The amp we just put in a cabinet drawer & it sat for at least Three Months. The thing is we have to store it & be responsible for it, but get paid Nothing to store it. It did eventually get paid for, without any 'hurry up' messages as then the customer may be wary of contacting & all the ensuing timewasting. What is a 'Reasonable Time'? The Family Shop way back had someone pay for some mirrors in a 1930s style, oddly got a Photo of them when they were fresh in, bevelled glass & grapes design, rather nice. But these were left & not collected despite paid. To leave them a year then resell was what happened, address of the buyer on the receipt was contacted & no response, but a year holding them is not good. One Month to Three Months is considered 'Reasonable' for tenants leaving goods, if for a Shop, it's not so clear. Note the Police dispose of abandoned-unclaimed goods after two months, if the owner can still come back after 5 years & you have to look after their goods. After a year the owner can still claim them back. You might actually like an item that is abandoned, you can freely use it, but it's not yours as the owner can still have rights. Best to avoid any nonsense in the first place.

Once You Get One Amp, You'll Want Another.
The Retro Looks will get you looking at more Amplifiers & Receivers. The Receiver looks more Retro for having the Tuner window, the Amps look more plain if have a different sort of appeal. Going back to the 1965-69 Receivers, they were usually Higher Power than the Amplifier version. There were less High Power Amplifiers & beyond UK brands, the Pre-Power two box set up was rare until around the 1977 era. They Sound Different even if we upgrade them in similar ways, each amp is done differently. The amount of Info about Vintage Hifi has grown hugely since the vague days of 2005 when Vintage before the 1977 'Monster Receiver' era were just considered Quirky Old Things. This meant we could buy A Lot of amps for Not Much, ones that are now expensive, whether selling for that or not. The Sound varies, to use our redesigned 1969 Pioneer SX-2500, a great receiver if messed up by too many designers. This has a punchy sound, a more dry precise sound with the Bass 'higher' in frequency giving a very Dynamic Sound on TV shows with suitable Soundtracks. To want a change is the Thing with having multiple amps & back to the 1965 Sansui TR-707A part Germaniums Receiver. It has a light hiss that doesn't bother us & is quite comforting, unlike the annoyance of Hum, Here the TR-707A has quite a different character. The midrange is a little more 'up' giving a better Presence. The 'higher' bass is different, giving a Deeper Bass that fills out TV shows that haven't got the Louder Noisier sections. This gives a more 'Friendly' sound & on Headphones the Soundstage is deeper detailed, which opens up the sound more. No Amps copy the design of the TR-707A or the 1965 Pioneer SX-600T, their Unique Sound is not going to be known by many & the rebuild costs of the TR-707A will put many off, if once you hear it, you'll understand. The SX-600T is only a recent find & not ready for speakers yet. The later Amps & Receivers past 1975 don't have the 'Musicality' of the earlier designs. The pointless quest for ultra low THD by 1975 based on 'guru' Tim De P messed things up, read our EAR Yoshino review of his valve anp to see our opinion. Also 1975 hit the 'Comet' heavy Discounting, yet by 1976-79 the 'Monster Receiver' era was a bit of a let down as 180w-300w amps vased on the cost-cutting & dumbed down designs resulted in big stupid amps that sounded Tame, we got the 1976 Marantz 2385 to see what this sort of amp was like. A lot of the post 1974 era is into ICs, Trio-Kenwood became IC riddled by then & other brands did too, the odd model is without ICs if still overdesigned with things like Three Differentials that further restricted the sound. Lower Power Amps & Receivers often were better sounding past 1974 as the more straightforward designs kept a Fresher Sound. Some low power amps are IC output blocks, some are All Transistors & these are the ones to go for. These are often still bargain priced. But to stick to at least 15w to have a decent volume on 95dB Tannoys, the 10w-12w ones we found are fine for less critical listening if are underpowered to us.

Amplifiers With Damage. What Else Is It Hiding?
The Car World knows a patch of Rust can often be a huge amount of Hidden Rust needing a metal patch welded in after the rust cut out. This is more advanced work, seen on 'Wheeler Dealers' & the other Car TV Shows. Getting Hifi with Damage is similarly into 'The Unknown' as only until any amp is properly taken apart does all the Damage show. We've had the 1965 Pioneer SX-600T recently & finding it needed 'Rare Spares' if we had them from a parts amp. Without them & other amps needing parts, they may not be useable. With Damage, you have to take it as 'Best Efforts' as the amp has to be heard Working & may need Repair to get there. One recent amp we knew had the Antenna broken, not so unusual. It didn't work said the Customer if they did show it switched on & lights working, this brand is notorious for not starting the Relay, so take it from there. Further examining of the 1973 Pioneer SX-1010 showed the Power Supply Board was cracked across if not fully broken. Knowing this needed doing & the rest of the boards looked fine, to take it as a job as we've fixed cracked PCBs before. Later the Board Repaired & it worked, very rough sound as probably unused in Decades, it actually needed 9 major repairs plus more minor ones. Too good an amp to leave Broken, to find the owner got it very cheap was good to hear, with it now working, even better. To see from the main chassis it had been dropped hard, not by a Courier as the packing was good in a wide box. The inner main plate of the chassis floor was dented in & the sides slightly dented. This has been seen far worse on other amps, especially one 1977 Yamaha CR-2020, but it all tidied well to be a good amp to sell. Vintage Amps are well made, a 22kg one is made with thick steel to give it that weight. Pleased it was at least working, onto taking the Fascia off. Small Hex bolts in the Tuner Wheel like previous Pioneer & why we had that small size from years before. But undoing the bolts & screws loosened the fascia & the glass decided to break on the Tuner Wheel hole & one of the buttons next to it. The hole has a plastic piece to keep glass from the metal that goes through it, but the drop clearly cracked the glass so it came loose from the fascia & there you are. This is the sort of Issue that is Hidden so you'd never know & glass is as fragile as it is strong. The Customer knows of the other Damages, we've sent Photos of the chassis bends plus the broken PCB says it's had a bit of a slam down. What To Do? You could glue or tape it to be 'intact' if obviously broken, it'll catch the eye. On ebay USA you can buy Repro Glass that's Clear not Tinted with the bit of wording printed. Having a small glass chip on or 1966 Akai AA-7000, as the Solds Gallery shows, annoys each time you notice it so best to get a new glass for the quality of the amp. Customer agrees to get the repro glass, we try our best to Solve Issues.

What Do Germanium Transistors In 1965 Amps Sound Like?
We've had Germanium amps before, the 1965 JVC MCA 104E was a good one. 1965 is the Last Year for Germanium, if dates on some are hard to tell, by 1966 Silicon took over. Except in the UK when 'Armstrong' were still using the poor UK-EU ones, in their 400 series from 1967 & 500 series from 1968, clearly they bought a huge batch that were obsolete. We've Blogged about Germaniums before, if now to understand them more in Our Upgrading Exploits. The 1965 Sansui TR-707A is all Germaniums on the Audio Stages beyond the final Driver & the TO3 Outputs. To get the TR-707A on 3 of 5 Germaniums on the Preamp Board was tricky as they can be Loudly Noisy yet not Test that way on reading with an Oscilloscope which is an odd one. To swap them around until 6 good ones of 14 were found, the first 3 per channel on the Preamp. The Germanium Noise on 95dB Speakers could be heard late at night, but in general Daytime Use it barely showed unless the TV show was playing quiet sections. It's a low 'Seashore' type steady hiss & not annoying, quite calming compared to silence. To keep doing upgrades & now deciding the TR-707A needed redesign beyond their Resistors design, it had been kept 'As Original' if the underside was done with New Resistors beyond the Inputs board as it has obscure values. Not to use Aux but 'Tape Monitor' means it bypasses this board. Redesign done, taking the 'Retro' treble slight smeariness away so to live with Germaniums to understand them, but it looks like TR-707A needs a try with All Silicon on the Audio Stages now. To learn Germaniums more, to get the rare 1965 Pioneer SX-600T that is All Germaniums beyond the TO3 Outputs. This one has a very crisp clean sound if does lack the more Powerful TR-707A, both are 25w rated. Oddly it needs +4 on Bass & Low Filter switch to 'on' to sound a fuller sound, checking the amp it's all correct. Another time. The 1965 Akai AA-5000(S) we tried to do Silicons on & it oscillated heavily on Treble, the design has too much NFB so the extended High Frequencies of Silicon turned it into an Oscillator. The SX-600T did nothing as the B-C-E voltages didn't suit Silicon. To redesign it using a later Pioneer design could work, but then you'd just clone another amp if the SX-600T is a great looker. To decide more on that one. TR-707A Back To Silicon. Probably the Only Germaniums amp you can swap Germaniums to Silicon & it works right. On Headphones sounds great, to try on Speakers on the sort of Voices that are Peaky with Germaniums. Verdict On Silicons in TR-707A. This seems to lack that 'Bit Of Special' the amp had with the first Transistors as Germanium. Volume gain a tiny bit less by the position of the Volume control. Playing the usual TV shows the overall sound just lacks a bit of the bite. Germaniums Amp Design made for these particular Germaniums & like the SX-600T it does sound unlike other amps. To use it more, but thinking to put the Germaniums back already. TR-707A Back To It's Original Germaniums. This time we've put 4/5 as Germanium, the extra ones weren't loudly hissy, one of our 2SB381 is, with 14 Germaniums to pick from as the Inputs Board is all Silicon, to try what you have & use 'Tape In'. Germaniums are certainly more Open Sounding than Silicon, to lack a certain Compression & give Wider Stereo. To Listen to the Music & then hear it for the Germanium Hiss, even with the Headphones pushed harder onto the ears, the Hiss isn't much more. The last Germanium, near the Power Switch is a Buffer Stage so has No Gain & it'll complete as all Germanium. Headphone out of the Amp Socket to hear 'Quiet' & then back in to hear the Germaniums. No amp unless overdesigned it totally Silent, here the Germanium Noise is worth putting up with for The Sound. The Right Side, with Volume at Zero, is slightly more Noisy than the Left, so swap in another one. We read HFE Gain on these & most were close matched. Replaced 2SB378A one is a better match L+R. Listening is the only way to Low Hiss Match. So try the last one as a Germanium, so the Preamp is 5/5 Germaniums. To be ultra fussy, the R is a tiny bit noisier, if the HFE match of the other possible is quite different & playing at the usual TV level the general Amp Hiss covers it. 10 out of 14 Germaniums good, one too noisy, one slightly noisy & 2 others, one of each 378A/381 not tried. Now to try on Speakers to hear how it does. Rare Transistors, maybe Sony Tape Machines have these, other TR-707A we've seen with replaced Transistors, not the Black Sony TO5 ones. On Originally getting the TR-707A, it was Very Hissy both Channels, so one or both the other Germaniums could be the Noisy one. But the 'Magical' Sound of it got it played & suffered the Hiss for The Art of The Sound. The TR-707A is as Fresh & Crisp sounding as the SX-600T is. Germanium is noted for being more Conductive than Silicon, Transistors are Semiconductors. Huge price difference is why Silicon took over beyond the Heat issues. We had some NOS 2SB407 TO3 Germanium 30w Output Transistors & they read leaky. Today Guitar Amp Users prefer Germaniums, if also the gritty Ceramics, all supposedly adding a Retro Sound. Another says that Germanium is not Flat & Plain Sounding like Silicon can be. Having heard Germanium & Silicon in the exact same amp, Germanium is the winner. Read the Guitar Amp guys opinions, guitarpoppa.com is one we read that goes more into things. Germaniums are usually PNP. The 1965 Akai AA-5000(S) uses Germaniums plus one NPN as a Silicon in the preamp stage. There are NPN Germaniums, mostly the UK-EU ones OC, AC etc. Japanese 2N1308 etc are NPN Germanium. There are the Military Spec Germaniums too, info on what the specs are is vague with only 'equivalent' books that we've found not too reliable. They can be long obsolete as NOS parts not being made in decades. Also there will be old amps etc that have them in to not totally be without options. The spec sheets of Germaniums need care for voltages & other factors. Germaniums TR-707A On Speakers. Matches better as 5/5 Germanium, a very smooth detailed sound & better Bass. Brings a nicer sound & as said just above, the Silicon sound is Plain Sounding. That page shows Germaniums gice a slightly slower Rise Time on Square Waves, it actually sounds fast on Headphones, seems to match better to Recorded Sound. How To Check For Loud Germanium Hiss. Not by an oscilloscope strangely, you'd expect to 'see' the noise. The only way to find a noisy one is to try them gradually when All Silicon is possible, or to just swap them out as L+R pairs, needing extra Germaniums to pick the best, 10 out of 14 is good.

The Problem With Really Great Hi-Fi.
You get really great Hifi, it's in Upgrades only & more extreme ones that are beyond what a Rebuild from us can bring. There are many problems Upgrading can bring in itself, to use Our Tried & Trusted Ideas works well & gives pleasing results, such a Better Bass, Losing That Grainy Sound as well as Reviving Rough Aged Amps. Going further can reveal certain amps can be "Too Good" as what you're listening to is only Mastered by Another Person who generally doesn't use such good Hifi or Large 15" Speakers to reveal things weren't Mastered Well. Above in the Germaniums Blog, the TR-707A was thought 'Peaky' for using Germaniums, but on doing all Silicon, to hear that 'Peaky' sound was actually in the TV Show Soundtracks. The BBC probably still use those LS3/5 type monitors, small bookshelf type speakers with low sensitivity that are going to Hide what a 95dB 15" Speaker will reveal. BBC often outputs very high edgy treble, sounding like the Microphone Peak around the 8kHz-12kHz range. Most amps & speakers won't reveal this peak, so it's not commonly known. On the opposite end of that, the TV show "Bangers & Cash" is mastered quite dull with the voiceover guy having a plummy voice that can sound too rich on some amps. To find the Peaky Treble sound on voices female & male can sound unnatural too, the Squeaky Female Voices on the TV USA Zoo Shows can be a bit much & probably are annoying in real life as it's a vocal tone that isn't really on female voices from other countries. A Nasal Girly Whiny Voice will sound Shrill & therefore 'Peaky' if it's Natural. USA TV Soundtracks go for a far more Bassy & Wide Stereo Effects sound that is much better on big speakers. Going from 'Bargain Hunt' where they don't mix the sound, one show their Boom Mic used half the early part of the Show was damaged as it had No Bass leaving a Telephone type range that was quite offputting, there seemed to be nothing under 500Hz which clearly they missed on their Tiny Monitor Speakers. The rest of the show used a different Mic & sounded as Normal, still very flat as BBC Soundtracks usually are. Some may fiddle with Tone or even Loudness to make up for the Thin Sound on TV, we just keep ours set at the same levels if volume can vary, some TV shows are with very loud bits & some are recorded or broadcast overall too quietly. Again the small Monitors wouldn't pick this up.

Old Fashioned Snobby Tired Views On Music In 1966-1967.
The Hi-Fi News Magazine from 1966-1967 shows such Narrow Minded Views on Music. The Only Music they mention as 'worthy' is Classical. The same old names with 'Mahler' mentioned perhaps the Most. But What Is Classical? It's Old-Fashioned Formal Music from 200 years ago. At the time, much Folk Music was around from Beer Drinking Songs to Sea Shanties. It will have been Sung in many places & the Religious Hymns will have been Music too. 'Pop' with the added colons each time, not to add emphasis but to hold 'Pop' out on a dirty stick like it's a dead rat is called Moron Music, Disposable Ephemeral Music of no lasting worth. 'Pop' means 'Popular' & in well-heeled circles, was Classical not the Pop of the 19th Centuy? Yes it was. Classical holds many strong melodies that are more familiar to us from use in Cartoons & Music of the 1950s & 1960s as we like & deal in makes Free Use of Classical themes without any credit. Classical has been well plundered over the Decades & probably even in today's 'music' be sure there are samples & steals of all types of music as Creativity has Gone. The Best Era for 'Pop' music is about 1947 when the First R&B arrived to 1985 when 'Live Aid' killed off music & made it Stadium Blandness. There have been occasional bursts of Interesting Music since, if Seventies Rock went with the Indie Groups taking a new style of Rock. The shallow Genre called 'Rap' started out with inventiveness but soon went too commercial, 'Vanilla Ice' copyist finished the authentic era. Having been into Music for most of our life, to see how 1950s & 1960s Music has grown in appreciation since the 1980s when it wasn't as widely known as it is now. Some Rare 45s are now better known than some hits, the Psychedelic Era being more Popular than the early Beatles 'Yeah Yeah' style. In 1967 the Pirate Radio Stations were Outlawed & the BBC brought in Radio One to offer a 'Pop' Station to the "dribbling uneducated simplistic masses" as the Classical Mob described who regularly revealed their ignorance & arrogance. Looking back, to see how Fast Musical Styles grew & evolved over the 1947-1985 era, yet since then or even before then, progress was much less to the point Today's Music is more Product & made to Fit, rather than any Fresh Thinking & Chance Taking. There are no Boy or Girl Bands, the Bland Pop Ballad singers were hugely popular as was the Simon Cowell created Bland Pop that helped put More Nails in the Coffin of Pop.

April 2024 Blog

Trio-Kenwood Adverts In Hi-Fi News 1963 To 1969.
Did this with Pioneer above, so to see what Trio-Kenwood were advertising in the UK to see when the KA-4000 amplifier arrived. The 1963-1969 run of HFN magazine we've thought to sell, but keep referring back to & having information from the timeis invaluable as to keep finding interest, so a Seven Year Run of the Most Interesting Era is worth keeping. The 1970-1980 run perhaps would still hold interest into 1973, but these are Huge Issues that we found rather tiresome when the 1963-1969 keeps telling more. Winter Trading advertises Trio-Kenwood product as 'Trio', later ads credit Trio alone, Winter being the London UK Distributors. Oct 1963 is the first Ad, runs Oct-Dec, picturing the attractive W-38 receiver. This a Two-Tuner unit for AM-AM Stereo & MPX FM via a Decoder, pity it's only a 7w RMS unit, likely 10w into 8 ohm as ratings still for 15 ohm. The ad shows Trio well established for Shops stocking the Brand & a list of products, Receivers, Amps & Tuners. W-41 amp, W-E8S receiver. W.40.J is an oddity as it describes the WX-400U receiver & later ads alt er the number if Dec 1963 calls it "WX-4004", it's the same '99gns' item. W.E-24 amp & W.10-10S receiver. Mar 1964 returns with a slightly altered range W-38, W.E-24, WX-400U correctly named, W-E8S & W-41U, with the lower priced W.10-10S receiver gone. May 1964 updates slightly to list 'FM Stereo' more clearly, adds a TW-30 'all transistor pre-main amplifier' if a 59gns price suggests low power. HFE has the Manual, it's All Germanium 10w rated with a 40v HT Power Supply, a small size unit 301mm wide. Aug 1964 unusually goes from their full page ads to a quarter page with only the WE-8S 7w valve receiver. Sep 1964 back to the May 1964 full ad again, adding more shops who stock Trio & runs to Feb. Mar 1965 updates the W-38 Two-Tuner Receiver to another Two-Tuner one, if the WX-400U is a full MPX FM unit. The W-10 is an obscure one, 7w reduced to 45gns suggesting an early 1963 model being sold off to clear, it's the W.10-10S one in their first Oct 1963 ad. Jun 1965 has the 1963 W-E8S now Discounted to 49gns, suggesting that Winter are trying to clear the early pre MPX ranges, W-E8S has FM MPX output to an MPX Adaptor like the AD-5U they picture on the ad, ad runs until Aug. Oct 1965 sees 'Trio Corporation' take over if still 'Winter Trading Co' the Distributors. Here the KW-33L appears. Has the 1966 looks, but an All Valve unit despite the 'KW' code. 9w into 15 ohm likely 15w into 8 ohm. Not the 1967 KR-33 we've had, this with the silver fascia & 4 rocker switches. The WX-400U advertised too, if no others, runs to Dec. Feb 1966 returns with the KW-33L ad & fgets the first page after the inside front cover. Mar 1966 still the KW-33L but adds 'Solid State' transistor amp TK-400E & tuner TK-500E. This is a Germanium Amplifier with a NPN Germanium in the power amp. Rated 32w, it's the Amp Version of the TK-80 receiver, the early version, ad runs to Apr, returns Aug after months away. Sep 1966 updates with KW-33L, TK-400E & TK-500E tuner only, runs to Dec. Jan 1967 a new ad with the 20w TK-60BE receiver displayed with the Top Off showing the Components, not seen any Brand advertise an amp like that before. Ad pictures TK-60BE fascia photo that's different to the 60BU Tuner by the numbering & the TK-500 & TK-600 again. The TK-60BE has All Silicon beyond a PNP Germanium Driver as seen with the TK-140E & other 1967 Trio before the TK-140X. No mention of the TK-80 of either version. Ad runs Jan-Mar. Apr 1967 hurries on with the TK-140E 50w receiver, the white switches one with Asbestos panels inside by the Transformer, making the TK-60BE & TK-80s old models still not mentioned. Often some Models are sold more in the USA if are available to UK. Shows TK-400E & TK-60BE still. May 1967 shows no UK Distributor, no Winter, but by July 1967 shows Winter sold out as 'R.E.W' shop is clearing out Trio valve gear. Aug 1967 same ad but B.H. Morris of London E1 now the Distributors. Sept 1967 updates, it'd be nice if HFN got the page number right, p362 not p368. Introduces the small 20w Amplifier & Tuner TK-250E & TK-350E with the black fascia, silver is easier to read so why change to a black fascia? Ask '1983' why too as the CD era was similar. Silver Fascia Amps were then 'unwanted & uncool' for many years until Silver returned. Has the TK-140E still. No Sep or Dec 1967 ad, missing a Dec ad suggests they lack new product. Jan 1968 returns with an odd floating Amp & Tuner combo as before, shows the base cover. Also these Ads start to be the USA ones with 'Kenwood' hand altered to 'Trio' for the UK market & you can clip a coupon for more info. Mar 1968 the same amp & tuner with a more typical stacked photo, returns July after months away. Runs for months until Nov, these always looked a bit Cheap without the Wood Sides the 1969 ranges had, if were Great Amps still. No Dec ad again, returns Jan 1969. Feb 1969 at last an update, the TK-20T with the Wood Veneer fascia corner & still the 1967-68 style rocker switches, but this again is only low power, just 12w after the 50w TK-140E will have put buyers off. Mar 1969 changes things, the appearance of the TK-140X as "200w Solid State" when it's 45w RMS to us. Odd they used TK-140 again after the 1967 "E", the "X" states Integrated Circuit as the Tuner has ICs in the IF stage & FETs in the Front End. Sadly to find these 1968-69 Tuners in Receivers that are working isn't easy, maybe the FETs fail? The ad shows the Supreme 1 which is a crazy Triple Amp idea to drive Triple Driver Speakers with different circuits, in a Tri-Amping Idea. How this can be any good with likely 'Time Delay' between stages & the issues of Limiting Bandwidth, try to find one, they didn't sell & no use to us. The TK-140X is one of The Best Receivers, the Fascia with the plastic knobs does cheapen it & later ones without the Wood Effect Lid lose looks. May 1969 brings the KA-4000 with the Silver Fascia again & smart Wood Sides. a much classier unit compared to the KA-2500 which is the TK-250E rebadged. Shows the KA-4000 came before the KA-6000 with both it & TK-140X being 1968 models. July 1969 brings the Supreme 1 back again by itself, clearly buyers weren't interested. Aug 1969 a full page USA style ad on the TK-140X. Sept 1969 a Double Page Ad for KA-2000, KT-3500 tuner & KA-2500, but after the classy KA-4000 back to these 'less pretty' ones. Ones to clear? Oct 1969 another bizarre one, the TK-20T is back, the Trio range in different styles needs sorting out better. Nov 1969 back to the TK-140X again. Dec 1969 back to the KA-2500 again. There Ends Our Trio-Kenwood History Tour. The KA-6000 was around early 1970 & later 1970 the range design changed again, again in 1971-72-73 before Trio unwisely went ICs making a Quality Brand into one that doesn't appeal much. The HFYB "List Of Amplifiers-Receivers' pages of ours show other Models not advertised, to think the KA-4000 sold well to not need advertise it & to clear the 'ugly' ones. Looking at the Catalogs by Brands, some Models will likely have been Special Order to the UK as ones Ahead Of The Market. Amps advertised a lot may not be so Common to find in 2024, the Trio ones KA-2000 & KA-2002 in varied versions you see most as Great Value with Nice Sounds. 1966 'Finds' For Us interest the most, TK-80 as two versions, valve-nuvistor-germanium with 80-108 tuner & a later Silicon version with 88-108 tuner. TK-60 as the 60U with push button powr switch & the later 60BU.

All Those Vintage Amplifier 'Repair Kits' on USA Ebay Are A Menace.
These Offer False Hope & do you really think £150 of parts is all an amp of possible rebuilt value of £1000-£2000 is worth. We've not bought any kits to see what they offer, do the parts actually fit? The Amateur being offered a Cheap Fix will often Ruin an Amp as it's far too complex. Tradespeople are there to do the Specialist Jobs like Wallpapering & Car Repair. If you want to Try It Yourself, then it's up to you, but we'd not want to be involved with an Amp Another Messed Up. Untidying Bad Repairs is a big job on top of the Actual Job of Rebuilding. These Kits only offer Like-For-Like parts, nothing 'Upgraded' will be involved & you'll be left with a Thin Sounding Overbright Amplifier sometimes. To see the Pioneer Range has lots of these kits as well as lots of 'Not Working' Amps for sale shows few are daring to try messing with a Complex Vintage Amp. Also if you are of a Semi-Pro standard to even attempt to Rebuild Complex High Power Amps, you'd Source your own Parts. The Simplistic Idea that just putting New Parts will solve All Issues just doesn't happen in Hifi Repairs. You can Do It Yourself, maybe it'll work, maybe it'll have problems you never expected. The Best Advice beyond sending it to a Tech & Paying The Price to do it properly, is to buy one already Rebuilt or just stay away from 50 year old Hifi as it's not for you. Seeing the prices, selling or not, to see Vintage Hifi deserves some Respect. We've bought Messed Up ones on ebay before, some could be rebuilt if needing far more work. Some the owner has done 'bad things' to & they are not of a standard that could be sold, so get Parted. We've Blogged this before & to say the Kit Buyers generally don't do the Job as it's too much. See the Hifi Forums, good intentions by Amateurs who ask questions showing they are Amateurs, but rarely does the thread finish with it Useable again. Sell it on as Original, it'll be trusted more to buy even not working, with good photos. Mess it up, be embarrassed & sell your Yamaha CR-2020 for £30 on ebay to get rid of it. We got one at that price, awful messing if made a good amp to sell, this was quite a few years back.

Tuner Dial Cord Re-Stringing.
The long piece of Cord that the Tuner uses can fail at any time, if thankfully Rarely. when it does, you can keep it in place with Tape, look at the Restringing Diagram in the Manual & seemingly Easy To Fix. Not so. The diagrams don't clearly show the way the Cord wraps three times around the User Control post & you can have done it nicely to have the Pointer travel the opposite way to how you turn it, as in Wrongly. Our 1965 Pioneer ER-420 just pinged the cord & having had difficulty with these. To look closely which way round it wraps the pieces. The Drive Shaft Diagram doesn't tell you well enough which way it goes, the cord in & out isn't drawn clearly so you'd be guessing. Looking at the cord that remains, as it broke by the side drum wheel, to see it 'goes in' onto the Drive Shaft towards the back panel side, wraps round three times & exits to go to the wheels below from the side nearer the fascia. Tie a new cord to the old one to try to make it easier & pull through. Set the Tuner Pointer to the gap in the fascia & the Drum Wheel to the position in the diagram, to fit it later. The Drum Wheel has the cord from the Top Right small wheel go to the Top then to the Spring, that's not clear either. The Cord from the lower wheel goes to the far small wheel, once round the Drum Wheel & then tied to the spring. The diagram isn't too clear & not having done one in ages, second time lucky. It's a pain to do these, but some need repair. The 1972 Trio-Kenwood KR-6200 had a broken post to which a wheel was fixed. This could have been why it got abandoned. Oddly it was still in place but had moved enough to make it less obvious. Why struggle with the diagram when we had a KR-5200 parted that had the Tuner Cord intact, so just copy it's style of doing the cord. Buying Cord. Look on ebay to see High Prices on what is used, how Rare It Must Be. Don't believe that, find an amount of Thick Thread like Leather is sewn with. To keep old tuner Cords from parted amps may get you 'real' cord but it'll probably not be long enough.

What Are All Those Diodes For?: Sony TA-3200F 100w Power Amp.
Earlier amps don't have all these Diodes on a Power Amp, so What are They For? Sony often circuit-explain to help understand what they are for. To Question any design feature to understand it or still not know. To alter things 'just to try' will usually end up needing New Transistors, so learn or leave alone is the best idea. On the Ta-3200F there are Twelve Diodes, some obviously the Bias & 'Overload Protection' ones. Whether these Protection devices actually work is another thing. Info based on what the Service Manual write-up tells. D101 is a Noise Suppressor to stop on/off noises, the 3200F certainly is quiet in use. It acts as a 'Current Mirror' like later ICs use & must stop Switching Peak Noises which can be annoying. D102 is the Bias Double Diode used in all Amplifiers without a Coupling Transformer. D103 protects Q114 in the Protection Circuit from failing when the Output is shorted, protect the Protection circuit. D104-105 aren't described if seem to be the 'Sensing' Diodes in the Protection circuit. D106 & D108 there is no D107 or D109, are part of the Protection, to assume this Mutes certain stages to 'warn' of a problem. D110 & D111 are to limit Power if the Output Stage is Shorted. D111 is a zener diode "1T243Mxx47" rated about 8v. D112 isn't mentioned, on the Emitter of one of the Power Transistors. The TA-3200F has Power Limiter on a 100w amp to 25w & 50w. To use this switch before using the Amp else you could heavily Clip the Amp if you set to 25w when it's putting out say 43w. The Trio-Kenwood KR-6170 uses a similar Power Limiter, if a short-lived idea. This uses D312-D318. To wonder why The User can't understand why a 100w amp should be used carefully on 25w or 50w speakers & not to switch back when in the higher power just shows the Ideas they tried. Power Limiting a User feature, Overload Protection to Mute the amp, but these ideas were Bettered by a Relay just turning the Speakers Off, here it could limit power but still leave a Damaged Output Transistor putting DC onto your speakers. The only safety is the Fuses eventually failing. Strange how the 1965 Sony TA-1120 had a Relay on the Speaker Outputs, when 'Off' it still played the Output Signal if at a much lower level. Sony didn't use Relays in Amps again until the 1975-76 range with the Sony TA-3650, the TA-1150 & STR-7055 ones had No Relay. Some brands used Relays in 1971 on Differential-era designs such as Trio-Kenwood & Marantz, if not on all models

Protection Stages Are A Menace.
The idea is that a Protection Stage is supposed to not put Full HT Voltage onto your Speakers. An amp with a Relay will cut out at 1v DC, at least as far as we've found on several amps. One cut the Relay past 1v with the Adjust very coarsely made so the tiniest turn gets it to cut the Relay, to use a difficult way to read the DC Offset shows the designers never bother to test ideas. The Second, the Protection is supposed to at least Cut the Audio when there are problems, we've told before of the Sony TA-1130 that fried the main transformer leaking the melted potting. To assume the user was running 2x 4 ohm speakers to put a heavy 2 ohm load creating the heavy current draw. But nothing cut out, leaving it getting to at least 150°C or more, with Epoxy Potting Compound showing it can stand 300-400°C which is a Food Cooker's temperature. See our Gallery for the TA-1130, it melted the Sony capacitor covers leaving them distorted. The Third One is a recent one. Fake TO3 transistors bought on ebay really messed up one amp, to do the usual repairs, but it was still not right & ruined the transistors twice more, this gets expensive at £30 a set of four. To try to trest it to see it was reading the full power as per our Test Tones & Oscilloscope as on the Power Ratings page. One side read full power, so to expect the other side to do similar, but past what would have been Half Power the top of the Sine Waveform clipped off, which trashed the outputs on that side & blew the 6.3A fuses. This is a bit much, it was considered a Trusted Amp to use on the Tannoys if the first Fake Transistor failure put 55v DC on the speakers, to be sitting right by the amp to power off fast, but later read the 55v on the Speaker Outputs. Amps left on when going to the Kitchen etc & could not have been caught so fast, the 'deathly' howl of a failed transistor is the only clue. The later Clipped Waveform was a result of their Protection Circuit breaking, the thing that's there to help fails itself! Had this with a B&O Beomaster 4400, the Protection Stage needed repair as parts had failed, was made working again.

Fault Finding In Vintage Hi-Fi.
This can take hours, days even weeks or months to get right, or even years if you've got sick of it & let it sit as some Amps are too worthy to break for parts. We Recap with our Upgrades to avoid wasting hours & customer's Money when to see others do this & just replace two small capacitors & think it's done right. No it's not, if two failed, be sure the rest are on the edge of failing too, only good to get repeat customers spending more than they should. There used to be a Deluded Pride with Amp owners saying 'the amp's in for repair' when all they get is partly replaced, rather than our More Bullish way of 'Do The Lot' & give the customer a rebuilt reliable amp. Cheaper in the Long Run if you're going to use it regularly, even daily & expect to keep your Speakers from gettimg damaged. Not Always Possible is a reality when Amps Get Damaged, in simplistic terms it's just a board with Transistors, Capacitors, Resistors & Diodes plus related like Rectifiers, Coils & more. But find which one is bad is the Black Art of Fault Finding. To check everything yet still have a fault is the Worst Issue in Hifi. It can take some serious thought to try to work it out, to run tests to check waveforms is very time consuming, if it'll still be a Component gone bad that holds you up. To find the fault means another one for you to know, nobody's that impressed what it was, but only that It Works again.

Controversy In 1967 Hi-Fi News Magazine.
We've read HFN from about 1987-88 on tiring of 'What Hi-Fi' & their monthly Best Amps which was pure Advertising Schlock, as if you'd find mid price amps that different by the 1980s. We've read the 1956-80 full set just short a couple of early ones so know the magazine well. It can be very lacking in the info you'd hope, full of outdated snobby views on music & still the mindless complex maths equations offered as reading matter. A lot of the magazine's interest is for The Adverts which show the era well, still depending on who advertised & changed the ads monthly, some seem to reprnt the same ad for months so it gets repetitive, if aiming to the more casual reader, rather than the Yearly Binder type. The Language used is as Outdated as the Cartoon Annuals we mention on our 'Books' tab on the end of Hifi Menu, with the 'Typewriters' page. The Kid's Annuals used Words Of Their Era if by 1955 ones, just as Rock & Roll was beginning, to see certain worfds & images was a little surprising, stereotypes & certain words seemed archaic, if not seen as offensive, just quickly outdated, if perhaps not to the ones creating the content. November 1967 issue was past 'The Summer Of Love', soon after Cecil 'Dust Bug' Watts had died & in a time more in the USA when certain people's rights were finally being realised, with Riots & unrest that should have woken up the mustiest mind. A Hifi Maker, James Sugden of the UK brand 'Sugden' was writing about Class A amplifiers that they soon introduced & had been putting text-only half page adverts about. A brand still around as we bought some amp buttons from them for the 1973 Sugden A48 Mk I in 2012. In the Nov 1967 HFN he uses a phrase that is remarkable to put in print in 1967 & from reading the HFN set already, it should have got complaints. He's trying to compare Transistors to Valves & outdated views by another he uses the "n... in the woodpile" phrase, the word in full, uncapitalised. It's an obscure phrase if a Tex Avery 1930s cartoon uses the 'image of a chap in a pile of logs' as a train roars by, logs jump up revealing him looking bewildered. In the 1930s even Baseball players used that word as a Nickname, so it must have been accepted if rarely used in print or said on film or cartoon. To think by 1967 it was 'not acceptable' to print that, but all those responsible, especially John Crabbe the editor, allowed it through. Not even the typesetter saw fit to alter it. Previous 'naughty' comments about Ladies Lingerie were pulled up by letter writers, their Brows Raised in Extreme we must expect. Looking at issues after this, nothing as an apology or any mention in the Letters Page. Clearly best to keep it quiet than draw attention to it, as the BBC still do today.

LED Bulb Progress: Non Flicker Ones In USA Now?
For the progress in LED House Bulbs, there are now AC/DC ones sold in USA, 10 for about $33 delivered. Asking one seller charging a premium price, they reply saying theirs have Built In Rectifiers to work on AC. Seeing they are the typical 29mm ones, 30mm ones are the omes we know more, these are Car ones & the Car Battery is DC. Most Hifi uses AC bulbs as made, only a few use DC. The Voltage of Car ones are 12v leaving the 8v or 6.3v ones either not too bright or not working as below the working voltage, 6.3v ones especially. We've tried an LED House Bulb when they first came out, as Blogged a few years back. It didn't last very long & wasn't exactly well made on breaking it apart to see what's inside. Regulators, Capacitor to smooth the Rectified AC to DC plus more PCB type circuitry. Hot running parts not exactly reliable, if not as bad as the melted wire & shorted older type twist bulbs. How Does It Make DC From AC? Rectified to create DC after adding a Capacitor to Smooth the ~~~ shaped waveform to DC as -----. Yes, but where is this Capacitor? How does that work? Electronics often don't use Transformers like older gear needed, the Switch Mode Power Supply as first seen in that 1979 Technics set we were rather surprised at, AC Mains direct onto a Resistor is hideous & a 1980 Sony amplifier on the 'Other Amps' page uses similar. But these amps & your LCD TV still uses bulky wet-insides type Electrolytic Capacitors, the 'Dry' capacitors or 'Solid' ones are still only for low values. Is This For Real? Looking at these 8v 29mm Fuse Type LEDs they look no different to LEDs we have here. The fact sellers say AC/DC is unlikely to be true, your amp needs a DC voltage. We put LEDs in our 1973 JVC 4VN990 by taking a voltage from a main DC HT voltage via a resistor. There is no other way & Google still doesn't say otherwise. Not believing this as we've not bought any. To see UK sellers have these & claim "AC" to ask them. Maybe the LED uses a Rectifier but not the smoothing capacitor? Looking at the 1971 Sony TA-3200F amplifier, it bizarrely uses a 2.5v filament bulb for the power switch light. These bulbs can be bought but don't last, so to just put in a LED screw type bulb we've tried in a 1967 Toshiba & 1967 Pioneer. In the Sony it barely flickers, in the other two it strobes quite spectacularly, especially the Toshiba one we remember. It's not the LED Bulb any different & these are from 2018 when these were just first around that we noticed. LED DC bulb for a Torch probably.

1967 Sansui 2000 Receiver.
This one out late 1967 as in the Jan 1968 HFN with oddly two adverts. One shows the USA type advert saying "A Full 100w" when the next advert fairly says it's 32w+32w RMS so likely a 30w RMS amp to us. !00w is the confusing IHFM peak music power doubled rating, adding two channels as one Wattage. This a little confusingly is the '2000A' from 1969 & '2000X' from 1971 to match the 1969 '4000' & the 1971 '5000X'. The first '2000' looks different with 5 rotary controls on the right, not the later push buttons on that side of the fascia. Not one we've looked at before, if seeing it's a 32w 1967 model, it's after the '3000' & 'TR-707A' so worth a look. Higher power than the '400' we've had & seems a higher power version of the 1970 '350A'. Front panel has push button power switch, headphone, a rotary, two push buttons then a row of 5 rotaries. Design. Tuner has a FET on the FM Front End then all Transistors, no ICs here. Aux still into Phono, 2 transistors for Phono, all Silicon by now. Preamp-Tone is 2 direct coupled transistors with NFB tone on a further transistor. Power Amp is just 6 transistors. Capacitor Coupled & not so unlike the '350A'. Power Supply still more complex like the '3000' if still Half Wave rectifying like the '400'. Verdict. Not that we've had one, but looks a more Standardised version with Capacitor Coupling after the '3000', if 1968 brought the very similar '3000A' still. Sansui with lots of models at the same time. 32w one amid 45w & 20w ones. Will be a good one as other Sansui are, nothing too special overall in design if setting the design for the 1969-70 ones as early as this is the interest.

1968 Marantz Model 18 & 1970 Model 19 Receiver.
This one gets mentioned in the Feb 1969 HFN. There is also a 'Model 19' with the Oscilloscope. It's a combined "10B" tuner, "7T" preamp & "Model 15" power amp. These are both USA made receivers, the "19" still uses the secretive coding for Transistors & Diodes, the Japan made ones start with the "2270" series numbering, so the "19" can't be from 1973 as HFE puts, it'll be a 1970 one, updating the 1968 "18". What's Offputting on these early USA made "Model" ones is the Manuals are already aware of problems, saying to alter things & over 50 years later unlikely you'd find the specs of these parts. The "18" notes several problems & odds are you'd be buying an earlier one with the problems, as these will have long been collector pieces. Bit of a shame to bypass them, if in reality it's a 40w receiver when they are a good few competing models from other makers. $650 new in 1968 shows it's priced like the 1968 Sony STR-6120. Hand calibrated Tuner Dial is a strange one, suggesting the components aren't well chosen or tight enough tolerance to use a typical printed paint-etched Tuner Dial window. There is a reason why Marantz moved from USA manufacture to Japan in 1970-71, leaving only Fisher & McIntosh as the main USA Hifi manufacturers, beyond more budget-midprice ones the UK never heard of. What's Nice is how well made they look, on the face of it, as with McIntosh & Fisher. They use UK-EU parts as those brands do too & possibly those annoying multi capacitor cans. Based on Marantz we've had, the 1973-75 ranges are the best sounding, the 1971 first Japanese ranges are a little lacking, by 1976 the scene had changed further to make cost cutting more appealing. What's Inside. Beyond the CRT Oscilloscope, an item that can age like old TVs, if it's faded then that's what you have. The Power Supply is strange, 8 taps from One Winding including Ground, why not use seperate Windings? Outputs many voltages from +200v to -300v. It can be wired to 240v as two primary windings. HT Voltage is ±36v so it's a Direct Coupled design, maybe Complimentary NPN-PNP outputs if the circuit isn't that clear to be sure, the 1968 Fisher 800T (500TX) was. Some Power Amp parts are exactly like that Fisher, which came first? The HFE manual someone added Voltages to, making the design clearer. To see design like the Fisher & a McIntosh MAC 1900 shows the USA boys were copying each other. Phono, Preamp-Tone & Power Amps fairly typical, no ICs in this amp. 'Service Notes' Problems The Manual Tells Of. This is a little offputting, but it adds up issues found by the '11-69' date on the Service Manual. It's like Bulletins other Brands issue. CRT Osc display can burn out if kept on too long, to the point of why have the thing & why need to see the patterns it creates. Loose Plugs, A wire to cut & resolder, Early Units the Zeners fail & stop parts working, other Reference Diodes need replacing as weak ones used, Low Filter button loud clicks, weak solder on Tone board, Tuner dial spring problems & inaccuracy, Ultrasonic HF Noise & involved way to correct it. This isn't very good, did they not actually have someone Use It before putting it for sale? It seems Marantz, Fisher & McIntosh were forever altering the designs. Other Brands did too, if renumbering very similar Receivers for Tuner changes, such as Pioneer SX-1000 from 1966-70 having the T, TA, TD & TW versions. USA Hifi Uses Secret Codes with Marantz Codes for Transistors, FETs & Diodes. McIntosh & Heathkit do this also, leaving you not being able to find replacements or know what to substitute it with. Get A Good One Or Get A Problem One. Unless you find one for $20 in a Thrift Store as USA buyers will have over he decades, to buy one online of a Tricky Amp is just Gambling. All you'll read is 'It Works' & on many amps you can tell if it's a good buy or an informed gamble. Here the Gamble Risk Is High for the known issues & to solve them today could be hard going. Or you might get an Estate Find that had all the Issues sorted long ago. The CRT glass tube isn't too bad on the Electronics, but the Tube itself after 55 years is going to be the biggest Risk that will affect the price. Marantz Model 19 is a manual we'd not seen before, on HFE now. It details issues like Hum. The strange one here is the Controls Pointer was set 'Flat' electrically, not as per the rotary middle of the control & could be very 'out' compared to set visually midway. Didn't get good quality Controls? Also Tape Monitor Noise, CRT issues 'replace it with a New One' they say. Does say how to change to 240v & the FM de-emphasis change. Does have a Relay. Does have those Multicap Can capacitors, 4x 2 capacitor cans. Which One To Choose? Both are quite similar in terms of the Audio Stages. The '18' has unique looks, the '19' looks towards the 1971 '2270' the '18' is more quirky. The small CRT tube can be fully turned off, if like Tuners, you'd like them Working as it keeps the value. Both will be in the £1000-£2000 bracket, bought from the USA with Shipping & Import fees making it possibly £500 extra. An investment in a good one & a proper Rebuild is what it'll need.

May 2024 Blog

Amplifiers With Passive Preamps.
Much in the Hi-Fi Press since the late 1980s with 'Source Direct' supposedly giving Input to Volume Control to Power Amp. Blogged before it's not what it seems as a Power Amplifier needs the Gain of a Preamp to realise it's Full Power. Example is the 1971 Sony TA-3200F Power Amp. It has the Input via a Switch saying 'Test' or 'Normal' which is best used on 'Test' as 'Normal' actually is a Bass Filter. Then the Input to Two Volume Controls for Left & Right, plus the 100w-50w-25w Power Limiter & Speaker selector for Two Speaker Sets. It has two inputs as 'Function'. We've tested this for Power Ratings & Power Amp only with a typical Line Level signal could only manage a 50w type Sinewave Output. With the associated Sony TA-2000F preamp set to the '1v' level it then reaches the 100w rating. Those using a Power Amp with only a Passive Preamp, the Volume Control are not getting Full Power Rating. You can use the Soundcard to add EQ like a Tone Stage would give. The TA-3200F as-is is exactly what a Passive Preamp would be, one of those Expensive Magical Boxes sold by 'Gurus' amid the Snake Oil bottles. Buyer Beware, but Magazines tell you they are better than a proper Preamp with Gain, all to sell such items. But not Full Power means you're just fooling yourself. What Does It Sound Like? It's a very Neutral Sound, Stereo is as Wide as the Best Integrated Amps, it has clean Treble if Bass is very tight & a bit thin sounding as it's not the Full Level of what a Preamp puts out, because it's not. Transistor sound with the TA-3200F, if we have tried this on Valves with the 1993 Tube Technology Genesis before we sold them. Valves were used direct from the Soundcard using the Computer Volume setting. This gave a slight background noise from the Soundcard as it was playing Full Level despite the internal one being adjusted. There will be issues of Impedance making the Valves sound nice but rather tame, but on both the lack of proper Bass & a Richer Sound are obvious. On the Soundcard EQ to add about what would be "+3" on the amplifier-preamp Bass Tone, ie +6dB at 31Hz, +4dB at 62Hz & +2dB at 125Hz. This does improve the sound hugely. The Sound with No Preamp but still needing similar with the EQ. Pulling the EQ back to 3, 2 & 1dB after getting used to the First EQ & finding it a bit too rich. EQ has an overall Gain upto 12dB on ours, 6dB sounds better if 12dB spoils the sound as it's the Max setting. EQ off it sounds a bit thin again, the 6dB of overall gain does add a 'Punch' to the sound. First Verdict. If you like very clean sound that's not too Bassy or too Upfront or Kicking sounding, Passive will suit, the Clean Treble & Mid, depending if your amp is a good design & recapped if a 1971 one. Try It With The TA-3200F Preamp. Ours is recapped & much upgraded from the rather disappointing Original Sound. The person we got both from nearly 6 years ago said they "Sounded Awful" & we had to agree to their gnarly limited tame sound, as designed. Playing on Headphones still, Headphone Box we made is on the Speaker Outputs, the Preamp has it's own internal Headphone Amp. We're Reviewing Our Own Upgrades here, we strive to Get The Best out of certain amps to the Point Of Obsession simply as we can & the amp seems worth it. TA-3200F set to Max with TA-2000F Volume control used. The Soundcard EQ turned off. The Bass-Richness is better, matches our EQ seting with the TA-3200F alone. The TA-2000F uses FETs in all the Preamp stages, Tone uses all 6, the 'Tone Cancel' only uses the first 3, a slight difference in freshness tells in the 'Tone Cancel' mode. The TA-2000F headphone amp is tried to compare both the Headphone Box on the TA-3200F outputs & via the Preamp, having it's own Headphone amp. The TA-2000F headphone amp is quite clearly a lesser item than the TA-3200F 100w power amp. Final Verdict. Using both Pre & Power adds more circuitry. Using the Pre with Tone On or Cancel adds more circuitry. The Power Amp only with the 3-2-1dB Bass EQ has an extra cleanness to the Pre & Power with 'Tone Cancel' but it lacks the Bass-Full sound of the Pre only. The 'First Verdict' stands if you'll trade Bass & a Richer sound for more detail that's almost Subliminal in the difference, it certainly takes a trained Hifi Ear to tell that. The TA-2000F pre & TA-3200F power amp can sound World Class. We sold ours in January 2024 just to move them on as the 1971 TA-1130 65w amplifier sounds very like them as original. Yes, a Raw Original Amp sounding almost as good as one Much Upgraded does show a bit of 'Tail Chasing' as more we've found since by May 2024. A lot of Hifi is Purposely Dumbed Down to Not Sound So Good. They do occasionally sell ones that are Better Than The Accountants would want selling. But interestingly the previous TA-1130 we had went the rounds with us getting it back once, the owners didn't like the Neutral Clean Sound. Do Hifi Listeners not like Clean Precise Sound? Do they prefer the Retro Bass Rough Sound? Until you'be heard 'Better Amps' & our Upgraded Amps, generally buyers won't know what 'Better' is. We think we've found the 'Best' then another comes along to better it, in a Surreal Way like they're waiting for us to find them. Crazy Stuff.

Compare The 1971 Sony TA-1130 To The Much Upgraded 1971 Sony TA-2000F & TA-3200 Pre-Power.
The Point of getting a TA-1130 again was to do this compare. The TA-1130 is still nearly original, so to compare both their Top Amplifier to their Top Pre-Power, not that there were other high power Amps or any other Pre-Power. Just to play it, best to forget previous opinions in Direct Compares. The TA-1130 is earlier than the Pre-Power Pair, it uses FETs in the Preamp & an Unique Power Amp that was done as similar versions in other amps like the earlier STR-6120, STR-6200F & STR-6065, as well as the TA-3200F. The TA-1130 preamp is 3 FETs including Tone which can be set Flat. The TA-1130 is an amp we know Others Don't Understand, it's not a rougher sound like a Pioneer had by 1974, it's a clean Neutral Sound. Has that Odd Volume Control that needs putting past halfway for a good volume, it's a 'Loudness' one if you can buy "Alps Blue with Loudness" from Japan direct. This TA-1130 is still a 1971 one from 52 years ago, but it's a lightly used one & still sounds great when other brands & other Sony models can be well past it. To say the Sony TA-1130 is perhaps one of The Most Perfect Amps is what we're hearing here. So for others not to like it or understand it seems strange. Our opinion on having one years ago, in 2011, was it was so precise but 'Not Too Exciting' which was from playing lesser amps that were far from Neutral sounding, horrors like the awful Radford HD250 amplifier & the dubious charms of Bang & Olufsen. Further listening to the same tracks the Sony Pair got used with reveals the TA-1130 overall sounds very like the TA-2000F set to 'Tone Cancel' on the TA-3200F power amp. But there is a certain sweetness the TA-1130 has that the Pre-Power together left sounding a little unfocussed. Very Nice Sounds from the TA-1130 as nearly original, but longer listening does reveal the fact it's on 52 year old capacitors still. Higher Treble could be a bit more extended. Comparing The Same Brand is an interesting one, having to swap in further amps only really adds a confusion as Tonally Amps All Differ. To use one for several days on Speakers or Headphones, either you like it or find it a little lacking compared to how another amp sounded days before. So Which Is The Best? Depends if you want a single unit amplifier or a double-unit as the pre-power. Both are The Best Of Sony to us.

Sony & FETs.
This concerns the 1971 range, later the V-FET 1975 range has FETs in the preamp & a set of Long-Obsolete V-FETs as Power Amp Transistors. For the price you see the V-FETs offered at on ebay, to try one won't happen with us & to actually trust an expensive Transistor isn't a Fake Relabelled item is just too high. The First FET amplifier is the 1971 TA-1130. Phono is one FET & one regular transistor. The Preamp-Tone is three FETs that are usually 2SK23A as we have fitted in ours. The Next FET Item is the Sony TA-2000F, an updated version of the 1970 preamp that is all Transistors & based more on the TA-1120(A) design. Usually the First Design of an Idea is the best one, the TA-2000F uses six FETs per channel, if three can be cancelled by 'Tone Defeat'. 100w Power Amp is called TA-3200F if it has No FETs. To see it is a later version of the TA-1130 Power Amplifier & the TA-3200F has two versions, one with mismatched size Driver Transistors & the later one with four TO66 size ones. This was as getting a good match in Transistors wasn't so easy, despite Sony themselves making Transistors, why not make a fully matched NPN-PNP pair?

A Question Of Voltage.
As time goes on, Amplifiers & Receivers we've had are pretty much Unfindable in the UK now. We & others have made these Wanted & some brands you will have to go to the USA or Germany to find. More Emerging Countries like Poland surprisingly had a good Hifi Interest so you can find them via HifiShark site, if payment & delivery isn't as straightforward as buying on ebay. Seeing a 'Wheeler Dealers' May 2024 in Poland, they seem quite like UK 1965-80 era, much nicer values, Blokes looking like Men, little trashy USA influence etc . That was nice to see. Most Hifi of Our Era 1965-1978 is Multivoltage, from 100-110-117-120-220-230-240v with some amps having all options. These will be Mentioned on the Rear Amplifier Label, such as the 1971 Sony TA-1130 says "AC 100-117-220-240v" which suits Japan, USA, Europe & UK. The rear panel of the TA-1130 has a black rectangular block under a plastic cover, unplug it & set to the required voltage by the Arrow. This great simple foolproof method we've seen first on the 1965 Sony TA-1120 & the 1965 Sansui TR-707A if early 707A have a more fiddly round plug that needs pieces soldered as per the diagram in the lid. Some Hifi is 117v only as the USA makers never thought about Exporting early gear. Some says 117 only but by looking at the Transformer Diagrams on the Service Manuals, if it has Two Primary Windings, the Mains side, it can be rewired 117v to 240v, or 234v to be precise. The USA made 1968 Fisher 800T (500TX) is said to be Multivoltage which it is, but to rewire the USA sold 120v wired one to UK 240v is a big job to do. You have to learn & identify the colours of faded wires then see where they should be wired & alter it. This is a tricky thing to do, get it wromg & you could ruin the transformer. As Illogical as that is, the ones that were Exported outside the USA will have been wired to the Country's voltage, never expecting anyone to need to alter it, but the Trade in Hifi Globally means most will just use a Step-Down Transformer rather than risk messing with AC Voltage. The McIntosh range is a USA Brand too, we had the C22 & C26 preamps with the MC2505 power amp back in 2002. The MC2505 power amp will have been Sold In The UK so was set to 240v. We wanted a Preamp so got the C26 first, it was 117v only if we rewired it looking how the MC2505 was done. To get the C22 valve preamp it was 117v only, info wasn't around in those days like it is now with HFE & other info manuals sites. To have recently got a MAC 1900 receiver from a customer, theirs was 117v only so needed the rewiring for 240v which we did too, but on this 1972 receiver, it didn't clearly say what to alter, to work it out the only way. We Can Alter Voltages If The Transformer Allows It. This is offered as part of a Big Rebuild Job only. It's not an easy thing to do & takes learning to check & check again making diagrams, before actually doing once it's seen as right, not a quick job or one to rush. As you'd expect, there are chancers out there, as blogged before, one buying the mid 1960s Marantz complex valve tuner wanted to offer £50 for it to be altered to UK voltage. As if we'd take their high risk on an unknown item & do such work that cheaply. Don't buy USA voltage Hifi & expect anyone to change voltages on certain gear just as a 'quick job'. To buy one from a UK Dealer & have it set to 240v & serviced is what they are trying to do on the cheap which usually ends up with an amateur ruining it. We try a 100v Japan amplifier the Lux from 1962. There are no 100v step down transformers we found. More later...

Ultra-Minimalist Hi-Fi: Is It For Real?
Are there Any Amps that are as near Minimal as a Passive Preamp on a Power Amp like the 1971 Sony TA-3200F is? It has Volume Controls plus Two Inputs, so if you can deal with No Tone Controls, there probably are very few Power Amps that have this Passive Preamp design. We don't know the USA scene of Vintage Power Amps as the UK doesn't see them, if likey there will be others, generally a Power Amp is just One Input with No Level Adjust. Modern, as in Post 1990 there may be ones similar, if to remember they are usualy stuffed with ICs & Op-Amps which are hardly minimal with 10-15 transistor stages per channel in these ICs & Op-Amps. Looking At Vintage Amps & Receivers for many years & finding some have a Low Transistor Count. The Tests above on the Sony TA-2000F clearly reveal the 'Tone Defeat' by using 3 FETs not the full 6 FETs is noticeably cleaner, this sort of Idea is Used in other amps as a -Tone Jump- as in 1975 Yamaha, which just bypasses the Tone Stage circuitry if still needing the Preamp Gain. The 6.8kg 1990 Pioneer A-400 is lauded by some as Hifi Perfection at a Budget-Midprice price. We've already been unkind to it on our 'Other Amps' page & added more to it in 2018 since the 2012 opinion. To see it got 5* ebay reviews yet once selling for £104, in 2023 they can be under £100 to £150, is that not telling it's a nasty cheap thing? A starter amp, but no Tone controls & now it's 33 years old it'll be borderline needing a rebuild. Let's look at the A-400 with 2023 eyes. Phono is FET differentials, one transistor then the expected IC-Op-Amp. No Hifi cred there & uses those tiny 1/8w resistors that are as small as surface mount ones. The Volume control comes next, beyond Input Selectors. It looks like a Passive Preamp as there is no Preamp, just Selector & Volume, but there is a resistor on the Volume acting as a semi-Loudness to tame the thin bright sound down, so it's not what it appears. Why C733-734 capacitors appear over a join makes no sense, circuit error? Power Amp the usual Differential with a lot of Taming to play safe & hide roughness to the Treble. More of the Power Amp circuit is well tamed, it's a dismal safe design, it may be tailored to 'fit' an accepted sound but it's far from honest. But neither was the 1965 Sony TA-1120 design. The A-400 is too contrived & tamed to be a true Minimalist amp, but to less experienced users it probably does sound decent amid it's competition, but as we joyfully said in 2012, it's still Grading Turds. What Else Is There? The No Tone Stage amps usually have an Op-Amp as the Preamp so aren't as Minimal as they claim to be. Generally The Hype on Amplifiers is Sales Hype. It's What You Think Is Best, having been told in these Paid Advert Reviews. Until you hear better, you'll just keep believing what is generally far from The Truth.

Ultra-Minimalist Hi-Fi: There Is One We Know...
The First Vintage Transistor Era 1965-67 throws up some Unique Designs that weren't repeated. There are Pioneer & Trio-Kenwood receivers that use about 9 transistors from Aux to Speakers out, obviously more for Tuner, Phono & Power Supplies. But there is One Receiver that is so Minimal it sounds like the Sony TA-3200F plus it has Tone Controls. The 1966 Akai AA-7000 is such an amp. Be warned it's Rare, despite three versions: solid wood sides, wood sides with thin grilles & a later AA-7000S version with a red tuner background & it was always a Silicon amp, with Nuvistors for the Tuner which are unlikely to have been updated in the 7000S version. We've had three of these, we got back the one on the 'Solds Gallery', you can see others on Google images, if the HifiShark site shows None at all. It's Rare & these were too aged to be used as Original. AA-7000 Design Is Certainly Unique. Aux is direct, not through the Phono board as the AA-5000(S) is. Aux to a Buffer Stage which only balances the Impedance, not adding gain. Then to totally Passive Tone Controls of good gain then to Balance then Volume that even has Loudness. That's it, beyond the usual Selectors & Switches, No Filters if has a Mono switch. Then onto the Power Amp. This is just Two reguilar small signal Transistors, a Driver, onto a Transformer to act as the Splitter. Autobias design, then onto the Power Outputs. Some add on extra transistors on the outputs, if others have none. Power Supply uses a Regulator which doesn't do much & the top board uses a Protection Circuit supplying the Power Amp Voltage to the first two transistors. So the Aux signal sees Just Five Transistors. A 1974 Pioneer SX-434 12w receiver uses Eight Transistors. A Valve Amp can be compared, using One Valve for Tone-Pre L+R (1 stage), some can use Two Stages to give better Preamp Gain. One Valve for both Gain & Splitter (2 stages) & then the Two Output Valves. Making 5 or 6 Gain Stages. Compare this to Overdesigned amps, many use a lot of Transistors & Differentials plus Protection Stages. 1971 Sony TA-3200F uses 14 transistors per channel, beyond Power Supply ones. Here not all are seeing Audio, there are extras for Voltage & Protection. Two for Differential, Two for Bias & first Driver, Two for NPN/PNP drivers then the Two Output Drivers is still Eight Transistors. The AA-7000 Is Unique. It plays with only a low background noise, much less than Germamiums, if the Transformer itself makes noise, if putting on two other amps gone is the TX noise. The AA-5000(S) uses 5 of 7 Germaniums in the Preamp, Aux goes through Phono. 2 others Silicon, T7 the Driver, T8 the Bias with T9.10 as Push-Pull Drivers then the T11-12 as Outputs. The Sanyo DC-60 is 6 Germaniums for the Preamp, Aux into Phono again, a Transformer Coupling as a Splitter than Two Silicon Outputs. The 1965 Pioneer SX-600T is all Germaniums, 7 used until the Silicon Outputs making 9 transistors. The 1965 Sansui TR-707A is all Germaniums until the last Driver & 2 Outputs. 7 transistors using Aux into Phono, 5 using Aux into Tape Monitor to bypass giving 7 or 9 transistors per channel. Germaniums Era Amps still have possibly more Transistors as the Germanium is Lower Gain than a Small Signal Silicon. The AA-5000 using Silicons was a huge oscillating sound as the Circuit didn't suit & the small transistors used had too much HFE gain. The TR-707A using similar style Silicons of lower HFE works fine. Whether the AA-5000(S), SX-600T & DC-60 could be made to work on Silicons would need redesign.

So What Do Minimalist Amps Sound Like?
Comparing both TA-3200F on Headphones & the AA-7000 on Speakers, to other amps, a clear 'OMG' moment on first comparing. The old cliché of 'Layers Of Cloth Off The Speakers' is certainly true as you hear deeper into the sound with Treble & Midrange just being Much Cleaner. It takes a trained Ear to hear this, one used to Neutral Open Sounding Amps. In some ways it's a 'Spiritual' Surreal difference but it's not imaginary. Perhaps the last 10-20% in Upgrade Terms if there are a few ways to keep getting the extra % that can leave certain amps sounding way short once you've Heard The Best. It's probably what the SET-Single Ended Triode 4w Brigade love, the sweeter than sweet clean sound, if SET valves with no NFB only play a part of the full 20Hz-20kHz sound spectrum. SET is mega-pretty but very flawed overall, just like our 1932 Pye G/GR radiogram puts out, an aged creepy but very nice aged limited sound. Of couse the smart-asses as read much in the 1960s Hifi Magazines would say if you Heard Music Live you'd hear a More Dynamic Powerful sound. In a Hall with Bad Acoustics & Lots Coughing, plus them playing Notes Wrongly that a Recording would edit out & compile the 'best' of maybe a few recordings, hopefully editing it better than 'Strawberry Fields Forever'. Lucky is the person happy with a portable Music Player, they don't need to bother with this Upgrading Hifi Lark. Minimal Amps are just another Flavour in the Hifi World. Minimal by leaving out Tone Stages, Mono Switches & not giving a Full Power is not Hifi to Us, if to try all there is. The Difference of one amp one day & another the next day will always alter opinions. An amp a little Dull Sounding or not fully Resolved can get Your Hearing Compensating. A 'Neutral' Amp next day can seem a little Bright from your Hearing Memory from the Day before. another Next Day the Neutral Amp will Reset Your Hearing Back. Hifi is often an Illusion.


June 2024 Blog

Facebook Hi-Fi Groups.
We see these on our Feed & to us, it's a little Disappointing to see endless amounts of 1980s-2000s gear, the sort of gear hyped by Review-Adverts in the Hifi Press. Many Fan pages with this one seen going more technical. 'Repair, Restore or Scrap it Audio and Video' which you can search for save linking. Our opinion on most of what they show is "Scrap It". It's the sort of unrepairable stuff we've long avoided. The awful cramped one board amps with blackened board patches from poor design not using proper Heatsinks is a Huge Problem in all Electronics. If an item runs more than 40°C it needs a Heatsink, Case Mounting or at least Free Open Air. But some items clearly get to 80°C to 100°C+ which is just Bad Design. The 1977 Yamaha CR-2020 a notorious Hot Runner with those Pathetic Top Regulators running 120°C with the Lid on. Clearly many like the Looks of Vintage Gear, the Huge Rack Mount Systems from 1979-82 get a lot of interest if do they get much use, most will just be for Display. A lot of this later gear is really So Far Away from how great the earlier Hifi can sound, if the Cost involved in Big Rebuilds puts many off, but What Are You Missing. They Seem Delighted With Their Hifi but we know these amps & don't rate them as the 1965-1973 era gear. A lot of Marantz, their amps sound clean but are generally Safe Sounding. Pioneer are heavily cost cut & sound so rough if the Designs are good, the penny pinching ruins them. The 100w+ scene is so Tamed it sounds so different from the Earlier Amps that are without all the Excess Circuitry & Overuse of Diodes. Hifi is a Game where you're Happy with Yours until you hear better. Better to Us is Upgraded with Redesign which is far from cheap. You can only Lead The Buyer to Greater Amps but they've not heard them at Home to know once you taste Upgraded, nothing else will do. Trouble is, who else knows the 1965-1973 scene like us? It's 50-60 year old amps usually too aged or tired sounding. Asking For Free Advice is part of Forums & Facebook groups, to see brief replies but notice No One Offers a Repair. From our site here, we used to get loads of emails thinking they will be told Our Secrets & How to do Complex things for an Amateur to do & Ruin the item. We stay off Social Media as it's all you'd be asked & forever have to monitor what is being Posted as often it's the amateurs answering questions. On The Positive Side it's a Drool Fest on the Vintage Hifi Scene, our Solds Gallery shown as a Long Page of Photos so you can see Lots Of Amps in one go. You see the Turntable Lids open, allowing Dust to settle on an LP with the LP cover in the lid as display. Sort of missing the point of the Turntable Cover.

Early Transistor Design Sadly Soon Forgotten.
The 1965-66 era of Transistor Amps & Receivers have some Unique Design that never gets used again mostly. This includes Design Features that are actually better sounding than the more Standard Design that ones from 1967 have. Firstly, Tuners with Valve or Nuvistor Front Ends for FM sound way better than the overdesigned IC & tons of Ceramic capacitor later designs. The Main Parts that are better are things like Transformer Coupling instead of the Splitter Stage, a Transformer doing the same thing must be more precise. Often these amps are Autobias meaning No Need to Adjust anything. There are a few later amps with Transformer Coupling as the makers reuse old designs, such as Akai AA-6300 & Nikko TRM-1200 plus a few other lower power designs in this 1971-73 era. Autobias is rarely used, Sansui 350A has just one adjust pot for Midpoint Voltage. Trio-Kenwood TK-140X & KR-6160 using the same amp board as in later TK-140X are two we know & again there could be others on lower power models. Main HT Regulation is only in the 1966 Akai-AA-7000. This is a great idea, to reduce AC ripple on DC to 1mV is exceptional. Some amps can have 400mV AC ripple which is poor design, the UK Ferrograph have this high ripple. The AA-7000 only drops 1v on the Regulator with 71v so it's a great idea as well as giving an extra quality, but as far as we've seen, no other amplifier uses this. Mains Chokes are from the Valve Era & offer a similar idea to a Transistor Regulator to reduce the AC ripple. Here they can work on high voltages like 500v & work well. In later amps you see Chokes, which are like a wound transformer, rarely. Some Retro Valve amps have them, if in Transistors the Sansui TR-707A is the only one using a Choke & they don't quite use it correctly. To use either a Choke or a Regulator, not both. Another Design that we don't see a name for, is the 1965-66 amps running 4 Hot Resistors on the Power Amp. Sansui 3000(A), Pioneer SX-600T, National-Panasonic SA-65, Akai AA-7000, Sansui TR-707A & Sanyo DC-60 use this. It usually works on Autobias with the Transformer Coupling. These Designs give a Great Sound, if some amps can be a bit more Noisy which is probably why they were Abandoned for the Low Noise designs by 1967. They can be Redesigned to sound quieter.

Early Opinions Of Transistor Amps. "The Transistor Sound" & 'Progress' From It
Reading the Hifi Magazines from when Transistors started arriving as Germanium then soon to Silicon, the opinions in the Hifi Press were Not Helpful & in all cases Actually Wrong, based on how many of these 1965-66 Amps & Receivers we've had. The only comment about 'Germanium Hiss' was one 1967 article about 'built in Noise Generators' for the background noise. There was criticism about 'Crossover Distortion' and actual Oscilloscope screenshots of a Sine Wave with a small kink midway. We've never seen this & for our Power Rating Tests, we see the Sinewave Output on all we test. Bias is added to a Class B circuit to give Class AB which means a Bias Voltage to smooth out the Crossover Kink, as in the NPN half crossing to the PNP half. If Bias is too low to expect the Kink, probably done to unfairly rubbish Transistors in the Hifi Press. Transistor Amps are a USA then Japanese specialty, UK's Quad only made it's 33/303 by Dec 1967 adverts if Leak Stereo 30 was out late 1963 with Germaniums & sold well. One commenter in HFN said that possibly the higher quality of transistor sound compared to valves was what the difference was, again Quad 33/303 out late 1967 still have the harsh Filter Slope control, which was more for covering Poor amplifier sounds that was the 'British Hifi Grainy Sound'. Letters in HFN regularly mention these deluded fools saying Vinyl was rough, yet never questioning the rough sounds from Quad & Ferrograph 'Hifi' & the primitive Cartridges still used. Crisper Treble is found in these 1965-66 amps, more precise than any other era & not a Valve sound. So as with cheap Rumbly Turntables getting Bass response reduced, now manufactuers found ways & there are several, to reduce this Fresh Crisp Treble sound to placate the whingers. This progresses so as Hifi goes on, the Less Natural it sounds. One recent amp we had is highly rated by those claiming to be 'Experts', yet to us the Bass is far too tight, ignore Damping Factor, the design is too bass tight. Treble is tamed to lose the fresh sound & just to add to the miserable sound, midrange is sometimes heavily restricted to soon sound rough. But because the worthless THD rating gave extra low numbers, Harmonics are way down in level compared to what Real Distortion is, this certain amp sounded well away from what the Source Music sounds like elsewhere, it's only playing some of the Source so what is it... 20% distorted, 50% distorted.

"Retro Electro Workshop" On UK Yesterday Channel.
You don't see much about Electronics from Hifi to TVs to Toasters. 'The Repair Shop' is quite limited in what it covers. The 'Vintage Tech Hunters' showed a wider range if not much Hifi related. 'Storage Wars' has Electronics as well as 'American Pickers' perhaps having a deeper interest. 'Pawn Stars' cover electronics but again more in the Gaming area. The Computer Gaming sysyems of old are more often seen as maybe of broader appeal to modern gamers. This is a new TV show in July 2023. The intro shows a wider range suggesting there will be more episodes. One wall shelf shows some Hifi, a 1968 Armstrong 421 amplifier, the stylish one swiftly replaced by the 500 series as the Hifi press were harshly critical of it, but it's not so unlike Braun gear of the era. also lots of Quad 33/303 'things' that aren't more than budget gear still plus a JVC receiver with the SEA EQ section. Episode 1: Here the Atari one as the first show is of minor appeal to us, if it does mention they have to deal with modifications. Depending what they are, we feel the need to modify on seeing poor design or just replacing obsolete parts. Watching them find the Atari, parts they can swap from others as so many of these around, but the show lacks a broader appeal. They don't put Info Boxes up explaining the History of the items. Shows like 'Bangers & Cash' and 'American Pickers' excel at giving info to help understand the items better, but not here. 'American Pickers' research items much deeper & source old photos of 'that sign up on the wall 80 years ago' giving extra interesting things explaining why they've made so many series, they keep it interesting. A few seconds talking about Atari history was the lot. We got bored with it, one guy in a shirt & tie in the 1960s tan jacket was a cliché too far & it didn't hold our interest. None of the reality of unfindable parts, everything ending up on the floor or losing a part or tool you just used. Nothing revealing the frustration of Electronics. The reward of Electronics is getting it right that covers & forgets the annoyance to get there. Things that should be simple can take hours & not be simple. The idea of putting things back to original isn't always the best idea or what a customer wants. Unlikely to be many series like 'Bangers & Cash' as the appeal here is lacking. Episode 2 with Sinclair C5 & Radio Caroline's broadcast gear. The C5 is on all the Tech shows & it's a horrible thing we're had enough of after 40+ years, but still quirky kitsch for those who'd dare drive it. Cheaply made in plastic on gears etc shows why they are usually non workers. The Radio Caroline section about the Tape Cartridges as was the fashion for Jingles, Capital Radio 194 used these. Again just not very interesting & skipped through most. Not enough Nostalgia shown to get wider interest, the 'Yesterday' channel makes lots of New Shows hoping for a hit & 'Bangers & Cash' certainly is. Some can be very boring like a Toy Auction one, again just dull. The 'History' Channel repeating all it's Collector Based shows like 'Auction Kings' & 'Auction Hunters' they are watchable as is 'Bid & Destroy' if some really overdo the "Hire In Rare" things fakeness, but it's more entertainment not factual.

Transformers. Half & Full Wave Rectifier. Single or Multiple Windings & Tappings.
We were never taught this at College, so to work it out on questioning why. Always Question what's not clear, it's not often the simple truth is out there. There are Half Wave rectifiers which are One Diode from a winding & the other side of the winding is Ground. It means in showing the idea via keyboard characters, assume the '^' is half a curved sinewave, then Half gives '^ ^ ^ ' when Full gives '^^^^^^' which after adding a Smoothing Capacitor gives a DC voltage with a small AC ripple. Half Wave rectifying is seen in cheaper units sometimes or for minor circuits, the 1977 Yamaha CR-2020 still uses one. What a Full Wave Rectifier means is two things. A Centre Ground Tapped Transformer only needs Two Diodes as the Centre Tap allows Full Wave rectifying. The familiar Bridge Rectifier is not suitable for a Centre Tapped transformer, it's for a more Simple Tapping without the Centre Tap. It can be used as + or - voltage, or if the - connected to ground, the + voltage only. It can be used on modern gear without a Transformer. Try to get sense reading online about that, what to search for. The Centre Tapped Transformer is a bigger & more expensive transformer. The Centre Tap Ground should go as near the Power Supply as possible. We're looking at our 1966 Akai AA-7000 to try to remove the noise, so question the TX design, which is fine, if the grounding on this especially as it has complex multi-cap capacitor cans making grounding difficult on doing as single cap cans. Multiple Windings are often seen on Amplifiers, a sense of isolation from the other circuits, if to see the 1968 Marantz Model 18 actually has 7 tappings plus a Ground Tapping on just one winding using +200v to -500v which seems extreme if Marantz thought it was a good idea & the thing works. The 1967 KLH 27 we tried to get a 240v transformer made, they couldn't make one that small size was their vague reason if to now see it was Centre Tapped on the single winding, using resistors for lower voltages.

Tuner Repairs Are Possible By Us.
We don't offer Tuner Repairs as generally it'll mean a Dead Tuner with absolutely nothing to start with. What's wrong could be Aiignment is wrong, usually from the Owner or previous one thinking twiddling the Ferrites (at your risk of breaking them) & Trimmer Pots will revive it, it never does if the tuner is silent. Once these are out then generally you won't get any sound. But one receiver, was dead on FM & AM. The 1966 Akai AA-7000 is a Nuvistor Front end with the rest as Transistors, a year before ICs arrived. The FM stage picks up a lot of channels, the sound is crisp with Tone added & we recapped it long ago, a sort of clean with a Retro softness & distortion to the sound, certainly listenable. Best with AFC on. The new transistors made it a fresher sound. The AM stage has voltages, but with no sound at all, even putting new transistors, it stays silent. It'd be nice to have it working, if who uses AM-MW these days, only has talk channels heavily compressed & limited. We're playing FM in Mono on it now, so we got success. Have blogged before saying to get the right Ferrite & Front End settings was by Measuring the depth of all the Adjustables, the Adjust Cans here are Double Ended & were all cracked from fiddling, to replace them is impossible as you can't buy the Ferrite screw type ones, if you can get ones from Parted Amps that are the standard size. As in get a Miracle Happening, go get the FM back, it's the only one we've had that Dead-Live transformation. New Problem. The Akai recently heard making bad bassy thumpy noises that crossed to the Aux as the FM stage is always on. Finding it part solved as a small film capacitor underneath was found broken off. Look at it to see what is is, look at our old Sold photos to find it & put another one in, again an unlikely fix. The noise was like Transistor rumbly noise we've heard. Not ever looked at the transistors, ours used 2SC536E small black dome ones. The first one on the MPX board we noticed was a small metal can one that had been replaced before, not neatly. It was a BC108 or BC109 as it wasn't that readable. This solved the noise if later it was noisy again, so just replace the lot. Will it work without any aligning is always the worry with changing tuners, have found this before. Here it worked fine & sounded better for our new transistors. Having to hear FM Radio stations means retuning a lot as the blandness of the music is hard going, good the AA-7000 picks up so many stations. Possible to play Classical stations if to us you're just hearing bits from TV, Cartoons & other songs which just gets you thinking of where it's familiar from. The 'MPX' board is less critical, if the FM 'IF' stages board with the 8 ferrites in 4 tall cans to adjust is where you will likely get trouble. To leave that board if the 'Muting & STB Board' at the front maybe the issue. No idea what 'STB' here means, but new transistors sorts the noises. Didn't fancy trying the FM-IF board, luckily it wasn't noisy. But it sounds better with new transistors. To Hear A Tuner is like old times as the radio was the thing, if getting bored with the music by finding much better Music on 45rpm from the1950s & 1960s. Hearing the empty bland music of today, pop or rap-hip hop & it's millions of names to hide it's not so different to 1979 still, it's just product now. You Are Of Your Generation raking through what The Radio played. Just in 'our era' there was such a wide range of music that introduced the Older Music. Would Music appeal to us as a Teen Of Today? Who knows. To get into Rare Records would be too expensive if YouTube has so much music to dig through, what to choose? Born In Your Era.

The 'Mid' Control On Some Amplfiers & Receivers.
Not many have this Midrange Control on the Bass & Treble Tone stage. UK's "Tripletone" amplifiers have this since 1961 as the name implies. Other brands picked up on this later, to know Marantz from 1971 & Trio-Kenwood from 1972, Yamaha call it 'Prescence' on the CR-2020. So to always try the Mid control on Speakers & Headphones, it's an interesting way to 'Match' your Speakers or the Mood of what you want to play. Mid set to minimum gives a background music style when Mid set midway would be too upfront. No real use for Mid to be on the Max side, if it's there for muffly DVDs of B&W films. On Speakers the amp may not match too well as the Midrange is too upfront, here you can pull it back. On Headphones it may be too dry & not as Bassy, so again back a few notches. But on Speakers it's more useful. So Why Isn't It On More Amplifiers, it's more honest than the Loudness button that is never what we use as it's too thick sounding with a gritty treble gain as usually done with ceramics. Is It That Good Really? How dare we question 'expert designers'. In reality they are just doing 'things fashionable' with Quality not always the main consideration. The amps with the 'Mid' control are usually a bit 'up' on the Midrange from certain design, to cause an issue by following the Crowd in Design to later correct & give as a good design. The 'Mid' Control on a Guitar Amp was used to The Max by 'Lemmy' of 'Motorhead' on his guitar amp, giving his hard unique sound. A rough & ready sound probably based on a tired amp but he liked it instead of a more weighty Flat or Bassy sound. Mid on an amp with the 'hardness' removed is only really any use for Mood Music to pull it back from a standard sound. As with any feature, especially Loudness, the fact it's there will get it used. Hifi Press used to criticise Tone Controls saying they are 'Redundant' or 'only good to Cut Treble on Rough Discs', unaware the Amp was the weakness needing taming.

Differences In Sound 1966 To 1972.
Using the 1966 Akai AA-7000 to get it to be the quietest background ever, with lots of redesign & upgrades it certainly has a Sweet Friendly Sound as well as vey crisp & chucking out Big Dynamics when TV shows play the louder backgrounds. A very minimal design as blogged abovem can there be any better sounding amp? Onto the 1972 Trio-Kenwood KR-6200 that seems to be the Best Trio made, the very similar KR-7200 also. Trying all the upgrades is is a very precise clean sound. But from the 'Mid' Blog above, we're finding it just a little too hard sounding, the analytical edge to the sound is so precise, the Bass is right, the Treble is right, but it's a little cold needing the Mid turned back two notches to sound 'More Friendly'. The 'Friendly' aspect of Sound is one of our making it seems, it's in so few amplifiers that often trade a pleasing stress-free sound for a colder harder one with limited Bass, unresolved high Treble & that awful Rough Midrange sound. If you've never heard the 'Friendly' sound to believe This Is What Hifi Is when it isn't. Does it Sound Natural is a big question to ask of an amp. Knowing Live Music sound as Acoustic & Amplified is your reference & it's one you can remember in a way you can remember old fashioned smells, like Rexine or Leaded Petrol. The lower models pre 1975 of 20w or less can have a Sweeter Sound than the higher power ones. Our Self-Quote of 'Small Ones Are More Sweeter' from long ago applies to other things in life that Bigger is Better is the general view, but that's a Mass-Market view. To get the Sweeter Sound into the Higher Power amps is not easy. To look at the designs of Sweeter Sounding Amps to see what they have & don't have is telling, not to put exactly what as that's our research & also from early pages here to find one idea is globally used by others as well as a Mania for certain amps. We're all Searching For The Best Amp & it's the one that gets used most, over the last few years the 1965 Sansui TR-707A has been used most if now fiinding the all-Germaniums noise a bit much as well as finding it can take a little redesign. The KR-6200 is a silent background amp, not too many are this quiet even on brands rated higher. Recapping revealed Noise that new Transistors sorted, now it's considered very precise but with that cold & hard edge. Can we get a 'Friendlier' sound from this amp? The sound isn't Natural by being too upfront needing 'Mid' Tone Control use that doesn't fully solve it. The KR-6200 is quite a modest looking receiver, midprice looks perhaps, Trio weren't the most pretty amps if their 1963 Trio WX-400U valve receiver was a real good looker. KR-6200 has a good relay which is reassuring to use on the Tannoys when not all Direct Coupled Amps have Relays. Put The 1966 Sound In a 1972 One? To find one that's otherwise very clean & precise with a lot of what a 1966 amp can do & with an extremely quiet background. Finding out by trying ideas, last tried the Trio-Kenwood KA-6004 similarly if other issues we hadn't discovered yet. To find a suitable amp, to get this KR-6200 as we had a KR-5200 as a parts amp, thought it was a decent one & to try this as a bargain buy with Speaker Connectors broken, when we had the KR-5200 to donate parts. The KR-6200 has done well to a point with all our ideas in, it's still on the Original 3 main capacitors, just to see how it does on Speakers when it gets tried. This brings a less cold & hard sound to the KR-6200 meaning a better Bass without Midrange too 'up'. Many designs just copy others without questioning, 1990s valve amps still copying the Mullard 1959 designs which go back into the 1940s. Yes It Is Possible. Sadly since the 1965-67 First Generation Amps, there were complainers about Bass revealing Cheap Turntables & Treble being too detailed, the 1980s amps were called 'Glass Cutting Treble' which shows all the weaknesses, dumbing down & cost cutting made Hifi Sound a mess & not really Hifi as there was better already made, in the 1960s. Not many amps can get to be Upgraded to show 'Their Best' as not everything is equal in Hifi Design. It may be too overwhelming to those used to the softer sound of 1971 Marantz compared to their 1973-75 sound. How many years researching this by us? Our Upgrades Aim To Offer 80% Of The Best Of An Amp without getting into Experimenting & Redesign which can take Years to perfect, or at least think it is until something else is found. Also it requires a willing amp to work on & take the experimenting. This means boards reasonably easy to get to & circuit track not falling loose on first taking out a component or forever getting loose or over-tight wires for thoughtless construction. The Main Problem With Deep Upgrading is you reveal weaknesses in the Design. Some can go 'all the way' & sound great, but to bring up Hiss, Hum, Switch Noises, Switch On or Off noises, plus bringing a sound that is 'too far' as the amp still has it's original design mostly. Some amps that sound Great to get annoyed with their Last Weaknesses, such as Hum & try to sollve it. How much of our 1979 Luxman LX33 valve amp is original design? Beyond the fittings the circuit design is ours & having to rwwire it to lose the Hum & add an extra Transformer for Heater Supply. Of course this can take Years to perfect.

What To Do With The 1965 Pioneer SX-600T, 1965 Akai AA-5000 & 1965 Sanyo DC-60
The Pioneer SX-600T is mostly Germaniums beyond the Output Transistors, Germanium may sound nice but it's Too Noisy unless you're playing Louder Music, it's not suited to TV with 'Quiet' programmes like 'The Antiques Roadshow'. An amp we bought expecting it to sound good which it does overall if not fully for the lack of a proper neutral sound. In 1965 buyers more used to a level of noise with some amps 'boasting' of -60dB or -70dB which will be noisy on a 95dB speaker as it will reveal -90dB noise in the dead of night, noticeable on turning off as the amp fades away.Here it's got the 1965 Sansui TR-707A sat on it & they do look very similar, who copied who? The receiver isn't as loud as the TR-707A & to get that gain as both are 25w, it brings up noise & still is lacking Upper Bass, so what is ot right with it? Maybe it was sold like this as a very clean crisp Treble amp but not really doing the sound evenly. Nothing wrong with it & the circuit resistors are as the Manual. To Do As Silicon is a hard one, look at the Voltages on the Germanium Transistors. These are ridiculously close, as little as 0.1v-0.4v apart B-C-E. The 2SB54 Germanium Transistor is used mostly with others. The HFE gain of these is more like a small signal Silicon transistor, unlike the TR-707A ones. Silicon needs at least 0.7v between B-C-E as it's the trigger voltage, Germanium is lower to work on the SX-600T design. It can be redesigned by altering the resistor values & getting the Silicon Transistor balanced to not clip. If the Voltage on a particular B-C-E is too low it'll clip the waveform, if it's too high it'll clip it in another way. Transistor Voltage Balancing is a fine art, you can work it out by Maths too. As with Valves, a transistor needs a Bias Voltage to have it conduct. Much online in theory. Germaniums are usually PNP, there are NPN ones if these aren't seen in the earlier stages. Here the SX-600T needs 7 transistors before the Outputs. To look at the Sanyo DC-60 as well, as both are good looking amps but unlike the TR-707A they've not been on speakers & the DC-60 has been considered a few times already, if not being too keen on all the problems & awkward construction. We've had the 1969 Sanyo DC-66 from a customer to rebuld, not possible to understand it too much with No Manuals, if the DC-60 we got the printed original manual. The DC-66 had a quality sound, the DC-60 does too if it's very noisy if quiet after the Volume control. The DC-60 has Germaniums beyond the last three, these are very low spec, 2SA202 we got one it needed on ebay, to find why is was findable is how weak it is, just 15mA, when the Pioneer & Sansui use ones of a more modern spec. DC-60 shows no voltages on the manual, to not overload such a weak transistor the design will be limited, some looks like the SX-600T. Also got the 1965 Akai AA-5000 that we sold after it being an ornament & bought another the day after the courier took the other one. We rebuilt the first AA-5000, it wasn't too great sounding in terms of not very crisp or precise sounding. Akai uses 2SB440 which are of decent spec & HFE which is why we tried to Silicon the amp, but the high HFB & a bit of Positive FB made the thing oscillate heavily. It's not easy to work on, so it's not a "User" either. It wasn't a noisy amp so could be recapped & used in it's Aged Retro way, very different to the 1966 Akai AA-7000. Helps us decide what to do with them. Three 1965 Germanium Ornaments, SX-600T, DC-60 & AA-5000. Great Lookers, but not going to be used by us. Sadly this seems the best option, the TR-707A lets you get good results as Germanium or Silicon. Not So, the Pioneer SX-600T by April 2024 is being used on Speakers, huge amount done over 11 months. As of June 2024 the SX-600T & others are now All Silicon, no more Germaniums for us in Amplifier stages. See future blogs, some of these Blogs sit a while before publishing.

Output Transistors: Change Semi Complementary to Fully Complementary?
One of those things you read on Hifi Forums to change SC to FC, as in 4x NPN to 2x NPN & 2x PNP. The Trio-Kenwod KR-6200 is a SC Differential design, so to remember this as it's worth a blog. Not for the Capacitor Coupled amps as these have a single +HT for the Outputs, it's for the ±HT Differential designs that are not Cap Coupled, a few don't have a differential but are SC. Why Would You Want To Change SC to FC. Good question. We have No Idea why or what supposed benefits it'd give except needing to buy NPN & PNP outputs, some of which are in Short Supply as of July 2023. It's not going to sound any different, so one to look online for answers, if there are any. One 'Electronics Tutorials' page tells some theory on it, but not how or why a NPN transistor can be used like a PNP in a SC circuit. Nothing much to find. So What's Going On. The SC takes the 'signal' from the Push-Pull Drivers, the last two drivers before the outputs. The Trio-Kenwood KA-6004 amp is a FC design, see the PP Drivers output is on both of the 'E' to go to FC outputs. The Trio-Kenwood KR-6200 receiver is still a SC design & takes the 'signal' from the NPN 'E' & the PNP 'C' to go to SC outputs. Just reversing the Polarity of the Signal from PNP Driver to NPN output for SC use. Is It Worth Bothering? With the first ±HT-Differential amps, to get a Matched NPN-PNP pair was difficult, look at 1971 Sony they couldn't get the same size NPN-PNP driver so some have the larger TO66 size for the NPN & the PNP a smaller TO5/TO39 size. By the time they used 4x TO66 on the 1972 later TA-3200F they were better matched. Shows Transistor Manufacture of NPN-PNP even by Sony who make their own Brand of Transistors wasn't really sorted until 1971-72. Lack of Availability & also to buy 4 Transistors from One Batch could mean they were better matched than two different NPN-PNP that shared the same specs. Modern Transistors are much more precisely matched, the 1971 Marantz 2270 offers a ridiculously complex 'Lissajous' oscilloscope curves way of matching the NPN-PNP drivers. The answer therefore is 'No'. Only to be altered by "Hair Shirt" wearers therefore, once Biased both SC & FC will be no different.