Vintage Audio
this section covers some restoration work that I did on my vintage HI-FI gear
Article #1 | 08:24 PM Sunday 03/01/2016

Introduction: Vintage Audio Restorations

This board presents technical information regarding the vintage gear that I restore from time to time.
Just to mention that I work slowly and most of these restorations span over many weeks or even months. Updates will be infrequent.

If you would like to view my work on audio amplifiers, please follow the links below.

AKAI Electric Company Ltd. SANSUI Electric Company Ltd. PIONEER Electric Company Ltd. Electronica Industriala
AKAI AA-5210 #1 Sansui AU-505 PIONEER SA-9100 IEI A-350
AKAI AA-5210 #2 Sansui AU-666
Sansui AU-6500 #1
Sansui AU-6500 #2
Sansui AU-7500
Sansui AU-8500 #1
Sansui AU-9500
Sansui AU-20000

If you are into tape decks then check my work in this field.

AKAI Electric Company Ltd. SONY Corporation REVOX STUDER

And if you want to see restorations of other audio devices please check the following articles.

ACCUPHASE Laboratory, Inc. DENON SANSUI Electric Company Ltd.
Accuphase C-200II Denon GT-700 Sansui TU-7500
Sansui TU-9500

Tip: To return to this page, always click the title of this site.

Legal: You are not allowed to use any of the images presented in this web site without my written consent. Also I would not be happy if I would see my images on auction sites backing-up restorations of sellable HI-FI gear. However you are allowed to use the images on repair topics in technical forums provided that you credit me as the source of the images and original work.

Article #2 | 11:12 AM Sunday 17/02/2019

About Vintage Audio Equipment

Driven by a growing frustration regarding the maintenance of various cassette decks, I have decided to write an about... section for each class of vintage HI-FI gear that I have an interest into. While it is true that in pictures you can see these marvels and make yourself a surreal idea about them, you should also know that all this equipment is very hard to maintain. If you want factory-like performance, that is. Otherwise they will work anyway in a degraded manner.

About Preamplifier and Amplifiers

Most vintage preamplifier and power amplifier units are still working by now. Even if not within their full mental faculties. But you can still enjoy their vintage sound. However I would say that almost all of them have drifted working parameters and should be restored.

Thankfully restoring such units is fairly simple because there is no precision mechanism to align and tweak. I would say fairly simple but people's perceptions on simple are vastly different. What I consider simple could be complicated for somebody else and recto-verso.

Normally restoring signal amplification devices is limited to replacing electrolytic capacitors, possibly small-signal transistors and diodes but rarely power transistors. In some isolated cases you need to perform debugging and reverse engineering of several unobtainable circuit sections. Sometimes oscillation tracking and damping is also carried. Finally idle current adjustment and DC offset output -- if available -- are the last steps before declaring the restoration over. It is funny that up until recently (early-2020) I was still convinced that small-signal (and not only) transistors actually contribute to the sonic signature of the unit they're part of. However I have changed my mind after lots of replacements that ended only with improvements.

Of course cleaning switches and mechanical controls is a tedious operation which in some cases cannot be overruled. So one must disassemble fragile mechanical components for thorough cleaning. I am absolutely against cleanup sprays and chemical substances.

Sure, once restored preamplifier and power amplifier units are rewarding and worth keeping around. They will not compare with similar new HI-FI gear -- think McIntosh or Accuphase; forget the sinister supermarket audio equipment. But these vintage units have their charm. They are still worthy of your audio rack.

About Cassette and RTR Decks

These units contain two main sections inside that are indispensable for a quality sound recording and reproduction. There is the high precision mechanism and the electronic circuits. Both sections need to be fully operational in order to deliver the expected specifications. Cassette deck peak was in 1988-1993. They were overruled with the introduction of the digital audio tape (DAT) and the compact disc (CD). Normally after all these years either the mechanism or the electronics are suffering. Or both at the same time. And what do you know: both require the right tools for alignment. If you don't have them, decks can and will sound like crap.

So where does my frustration come from?

Let me explain. Over time I had about fifty cassette decks and I parted ways with almost all of them. The truth is that I had these over the time they were pretty much standard audio equipment. This means I haven not experienced problems with most of them. But I finally settled down to only a couple of cassette decks and one reel to reel tape deck. I believe these are going to be my last decks. But all of them have issues more or less severe. Nothing that cannot be corrected though. But scarcity of precision mechanical parts quickly renders these machines as inoperable and expensive paperweights.

Let's take the machines one by one then.

  1. AKAI GXC-760D: Main transmission belt, worn out pinch rollers, dry capstan bearings, severe wow & flutter, dried out or cooked capacitors, burnt out light bulbs, direct-drive reel motor faults.
  2. SONY TC-K850ES: Main transmission belt, mode belt, worn out pinch rollers (especially supply side) and leaky capstan motor controller filtering capacitors.
  3. SONY TC-K555ESA: Main transmission belt, worn out supply side pinch roller, leaky capstan motor controller filtering capacitors, misaligned tape path -- this is again, bad.
  4. REVOX B215: Dry capstan bearings, worn out pinch rollers, dried out or shorted capacitors, broken IR tape detector.
  5. STUDER B67 MKII: Dried out or shorted capacitors, worn out pinch roller, burnt bulbs, several other minor defects on various printed circuit boards.

Whenever I want to listen to a tape I get angry because neither of these decks is not in 100% functional state. You can't even imagine the frustration arising from loading a tape and after 10 minutes of playing or so, the machine starts meowing with loads of wow & flutter. Of course there is nothing that I cannot fix. But the amount of time involved in these repairs is outrageous. I have other daytime duties as well. Often I find myself running out of time and the thought of maintaining these decks just for listening to old mixtapes is slowly eating me from inside. I often think about digitizing all these old cassettes and sell all the decks. But then I remember the good old days when I spent my time sorting music and recording it on these tapes. Oh and I almost forgot. A tape recorded on one deck almost always doesn't sound the same on another deck. And I am not referring to sound qualities but alignment. And almost all of my decks have factory aligned heads. So head wear should be taken into consideration. Once heads are off course, there is nothing that can be done to restore them. New heads are practically unobtainable. Sure GX heads are slow wearing devices but they too have quite a lot of running hours by now.

This leads me to speak about cassettes. I had a lot of them over the time but now I have less than one hundred (100). Mostly CrO2 tape formulation. Music is mainly Italo Disco ('80s) and Eurodance ('90s) but also some other genres. I don't want to destroy these old tapes with misaligned machines. Disaster waiting to happen. Tape chewing is a real issue and deck is stalking you. When you are not aware it will eat the tape ruining your precious audio memories.

Sure once restored and properly aligned, decks are exceptionally rewarding. Seeing the precision mechanism at work combined with hearing the exceptional -- for the late '80s that is -- electronic circuits is a mesmerizing experience. As long as it lasts. If it lasts. These are old machines and issues are waiting for you behind the corner. Compare them with old cars if you want. Would you risk driving a '60s (muscle) car on the highway for a couple of hours at a steady 130 km/h? Even if restored, I wouldn't. So what's the point on having 5 old cars when you could sell them and buy only one new car? Maybe I should do the same with cassette decks. Sell all of them and buy only one. But which one? All of them are (very) old by now. I reckon maintaining these decks is a dying art already.

So there you go. Keep these lines in mind should you ever want to buy a cassette deck.

About Tuners

HI-FI radio tuners are very nice devices as long as they work and there is a quality radio station around where you stay. If they are misaligned then realigning them is insanely difficult even with adequate test equipment. If you have no quality radio station around then there is absolutely no point in owning a radio tuner.

Possible easily fixable defects include, but are not limited to, burnt scale bulbs, crack and pop noises from bad transistors, and faded flat sound due to bad capacitors. Easy to fix and rewarding after all.

If I were to choose a radio tuner, I would search for a 4-gang variable capacitor analog tuner. I have had top of the line quartz locked digital tuners from AKAI and Sony and while they were incredibly well built machines, oozing technological advancements, they sounded different than analog ones. Not bad, but different.

I am lucky that I can listen to at least two nice FM stations and at least one AM station. Emission quality is not that good but the musical selections are very nice. News programs are quality as well. But when these stations will cease emission I would retire the tuners forever. And unfortunately this will happen some day. Now everything happens on the Internet, remember?

About Turntables

This is a different category of vintage beasts. I am not very experienced in this domain and I have not serviced more than three turntables in my entire life. Sure I owned various models in the past but I ended up parting with all of them. Now I only have one turntable at this moment and I consider that it fulfills my needs with minimal maintenance. It is a very old model that is still working well give or take. Well once it heats up, speed drifts upwards a little bit. It is easily correctable through the RPM control knob. But then again, there is nothing that I cannot fix.

As a general advice for the casual turntable buyer: avoid junk. Better wait and raise funds to get a good turntable. These are very picky machines and sound quality suffers a lot if misaligned or lower quality cartridge is used.


Owning and maintaining vintage HI-FI gear is a time consuming task. You need to clearly think about it. Does it worth the time you invest -- or loose -- in maintenance for the few hours a week when you use them? A computer could deliver constant audio performance at any time in the day or night. There are better uses for your time. But if vintage audio equipment is your call, then I can guarantee you will enjoy every moment you spend with your HI-FI gear. Otherwise I am issuing a simple warning that could save you a lot of time: raise funds and buy quality new gear. Sure they have several orders of magnitude higher prices. But they will last you a lifetime without hassle. Hopefully...

You know better what suits you. Don't let yourself fooled by what people write on forums or auction sites. Judge for yourself, experiment, and only then take your decision.

your help matters

Please note that all the work presented herein this site is non-commercial. This is my hobby and I am doing this in my spare time. Through this page I freely share my knowledge with you. But if you like my work, please consider helping me buy a transistor or a capacitor for my projects.

Thank you!

Copyright © 1998- Alexandru Groza