Yamaha A-1 Vintage Amplifier Review

[Sonusfaber]

I used to own a Yamaha A1 amplifier from 1980, together with a pair of B&W DM7 (first gen). I was quite happy for years, but did find out that the power amp could be much improved on. The preamp including phono pre, turned out to be really good, even many years later. I don’t recognize the noise issue at all, on the contrary, it was a very silent amp...

 

[John1959]

I just came across this topic about the Yamaha A-1. I inherited a black one, bought by my dad around 1980 or so. It's in my basement now for some 15 years. I don't know if it's in good working condition. Will try soon. Price was about 1700 Dutch guilders (about 800 euro) which was a lot those days, especially for an integrated amp with only a modest power output even for those days. It had a relaxed, laid back sound. Note that the unit came with some plugs to match impedance of MM cartridges, which is quite rare I think. The MM phone amp is oké but the MC amp is noisy.

I also got from him legendary Yamaha T-2 tuner, one of the best tuners ever made. Looks nice on top. Quite different as the mainstream those days.

BTW, there are two massive transformers in the A-1, not one per channel but put in parallel to "cancel leakage flux " or something as stated in the manual (?). Also, there is no real pre-out with this amp. That "pre-out" comes directly from the main amp. That's why there is no separate input for the power amp I guess.

Another interesting detail: there is no separate balance control. The big volume control consists of two concentric knobs (so in fact dual mono). With a dual mono ALPS potmeter behind it.

Unfortunately the door with the controls behind is broken off but I still have it somewhere.

 

[restorer-john]

I just came across this topic about the Yamaha A-1. I inherited a black one, bought by my dad around 1980 or so. It's in my basement now for some 15 years. I don't know if it's in good working condition. Will try soon. Price was about 1700 Dutch guilders (about 800 euro) which was a lot those days, especially for an integrated amp with only a modest power output even for those days. It had a relaxed, laid back sound. Note that the unit came with some plugs to match impedance of MM cartridges, which is quite rare I think. The MM phone amp is oké but the MC amp is noisy.

I also got from him legendary Yamaha T-2 tuner, one of the best tuners ever made. Looks nice on top. Quite different as the mainstream those days.

BTW, there are two massive transformers in the A-1, not one per channel but put in parallel to "cancel leakage flux " or something as stated in the manual (?). Also, there is no real pre-out with this amp. That "pre-out" comes directly from the main amp. That's why there is no separate input for the power amp I guess.

Another interesting detail: there is no separate balance control. The big volume control consists of two concentric knobs (so in fact dual mono). With a dual mono ALPS potmeter behind it.

Unfortunately the door with the controls behind is broken off but I still have it somewhere.


View attachment 89198

Well, what I want you to do is take your Dad's amplifier and tuner outside and blow out all the dust, spiderwebs and whatever has crawled inside whilst in your basement. Then give them a thorough cleaning. All knobs, switches and panels, terminals, that headphone socket looks crusty.

Then post a picture here with any issues you have discovered while testing it. Your Dad bought well back then, it's your job to give the Yamaha gear another 40 years.

 

[John1959]

Here a picture of the internals. A lot of dust but no corrosion, at least not visible through the layer of dust! I remember that I have replaced some bulbs 15 years ago. I also tried to replace the noisy ALPS potmeter but I could not find a good replacement through the local parts shop then. As I said it is dual mono (not stereo). Do you have any suggestions? Also those ALPS where also very expensive those day, about US$25 or so. After that I put him to rest in the (dry) basement and never touched it until yesterday.

BTW, other nice detail. The RCA connectors look cheap (no gold) but actually are rhodium plated whcih is more durable. So nothing cheap here!

 

[restorer-john]

It takes the amplifier outside and hits her with an air compressor and a carefully used paintbrush.

She's so purdy. The Alps black beauty (the name for that pot) is easy to remove, dismantle and clean. Be gentle.

Such a great amplifier to have. Enjoy.

 

[Labjr]

I saw a thread on Audio Karma on cleaning an Alps pot. Of course you'll need to use something like Deoxit D5 which is probably half the cost of buying a new pot.

 

[John1959]

I saw a thread on Audio Karma on cleaning an Alps pot. Of course you'll need to use something like Deoxit D5 which is probably half the cost of buying a new pot.

Yeah, after cleaning the amp I will try that. Also, I have to go this route anyway because I did some research and the ALPS "Black Beauty" are rare now and ridiculously expensive (US50 to US$ 100 ore more) on ebay, even for a used one.

 

[Asmodeus2112]

Yeah, after cleaning the amp I will try that. Also, I have to go this route anyway because I did some research and the ALPS "Black Beauty" are rare now and ridiculously expensive (US50 to US$ 100 ore more) on ebay, even for a used one.

Yes, it can be hard to find certain parts. As John has said, be gentle. Do you have a DBT (Dim Bulb Tester)? Might be a good idea for the first time you turn it on if you haven't yet, or if you do any work to it. I have seen 3d printed hinges, so if you have the door you are in a good position.

 

[John1959]

Yes, it can be hard to find certain parts. As John has said, be gentle. Do you have a DBT (Dim Bulb Tester)? Might be a good idea for the first time you turn it on if you haven't yet, or if you do any work to it. I have seen 3d printed hinges, so if you have the door you are in a good position.

After some cleaning with an air compressor I started her up and here seems nothing seriously wrong with this 40 years old amp, except noisy potmeters which I will clean. I checked it with the also 40 years old Yamaha T-2 FM-tuner which is still working too. I don't have an antenna but a simple 1.5 meter wire dipole did the job to pick up some signal, though it's all about digital radio (DAB) these days. My dad had a large 10 meter high rotatable 8 or 9 elements antenna on the roof of the house, only for FM reception!

BTW, I found the service manual for the A-1 on the internet so I may check some voltages later. I don't have the meters for checking the caps. Asmodeus2112, thanks for the tip about the hinges!

Internals after the air compressor did his work. Most of the dust is gone but still not very clean.

 

[cistercian]

Wow...that amp looks sweet. Good luck to you!

 

[restorer-john]

Internals after the air compressor did his work. Most of the dust is gone but still not very clean.

I'd like you to clean the black (dust/carbon) off the Disc switch PCB (centre top of the picture) and the tone board (the board below). It doesn't look too bad. Just use a paintbrush and methylated spirits/rag. Dry it off with a hairdryer.

The 2 gang Black Beauty Alps pot of course is under the PCB. If you are not good at desoldering- leave it alone as the connections to the internal substrate can be delicate in their old age.

If you simply exercise the pots by rotating them back and forth many times, you will likely cure the scratchiness temporarily or until you feel like you want to takle the pot and dismantle it to clean.

I wouldn't worry about setting and voltages or checking the bias right now. Just give it some exercise and see what issues (if any) arise.

 

[Dersch]

Interesting read on data for a product (Yamaha A1) that when I bought it over 40 years ago for $600 cdn, was deemed “ahead of its time”. I look back now as I still own this piece, with no issues, and smile

 

[mercator1]

I've still got my A1 Amp and T1 tuner hooked up to my JBL 4308 monitors. I previously sold my K960 DBX cassette deck, and gave my neighbor my P2 linear tracking turntable (along with all my albums).

The Amp has something going on where it will just click off randomly. Power is on, but no speaker output. Someone with skills I lack could probably repair it fairly easily. As much as the sound quality was all I cared about in my 20's, convenience has won out as I hit 60. I'm going to try and find a good quality connected Amp to replace them.

The Amp and tuner are too heavy to ship (especially the amp), but if anyone is near Birmingham, AL and wants them, I'll practically give them away.

 

[Asmodeus2112]

If you would be willing to box them properly I am willing to pay for shipping plus what you want for them. PM me if you are willing. I enjoy fixing amps as a hobby and love Yamaha. It sounds like the protection relays are tripping on your amp. That could be due to the DC offset being off. On this amp that can be adjusted. If you are handy you might be able to take that first step, or if you take it to a tech they may not charge much for this. It could be other things too, but that is a start. IMO this is an amp worth fixing and restoring. Having the tuner is nice for the collector.

 

[mercator1]

If you would be willing to box them properly I am willing to pay for shipping plus what you want for them. PM me if you are willing. I enjoy fixing amps as a hobby and love Yamaha. It sounds like the protection relays are tripping on your amp. That could be due to the DC offset being off. On this amp that can be adjusted. If you are handy you might be able to take that first step, or if you take it to a tech they may not charge much for this. It could be other things too, but that is a start. IMO this is an amp worth fixing and restoring. Having the tuner is nice for the collector.

You lost me in "if you are handy...".

If you'll send me your zip, I can get a quote on shipping. That amp is a beast though. The tuner isn't too bad.

 

[Asmodeus2112]

You lost me in "if you are handy...".

If you'll send me your zip, I can get a quote on shipping. That amp is a beast though. The tuner isn't too bad.

PM'd you.

 

[Mastergr00ve]

Hi, is there anyone here who currently owns this amp or does he know it as well as himself for some temperature concerns?
I have one that I have just restored but I have doubts about the heating of some components.

 

[Asmodeus2112]

Hi, is there anyone here who currently owns this amp or does he know it as well as himself for some temperature concerns?
I have one that I have just restored but I have doubts about the heating of some components.

Check your post at Audio Karma....

 

[NoxMorbis]

50 years ago we also had CB radios. Personal computers were also just rolling out.

Geeze. I rember going on a vacation trip with my parents in the summer of 1977. One of their friends, who owned an electronics shop in town, convinced our caravan (three cars and trailers) to get CB radios). We had a lot of fun with those things while on the road. They got retired immediately after getting home lol. What a memory you brought back.

 

[NoxMorbis]

Even according to manufacturers' specification, the distortion is never as low as -100db at 1000hz and it's only lower than 0.01% at 20khz. There are always people talking how many zeros those 70s manufacturers got. It's completely utter bullshit. It's barely blameless in standards now(omitting the ps noise).

I'm seeing the same thing. Our low tech class D amps are nearly if not even better than some of the better rated "hi-fi" in the 1970s, at least vs this single sample. I mean, it's old too, so there is that concern. However, you can still look at the included specs if you trust them. It's pretty amazing that a $150-$200 (or even less) class D amp tests as good as they do vs older tech like this.

In 1983, I had a Yamaha that looked identical to this R700, but mine was 70wts a channel and this one is 50wts, so I have no idea what it actually was. No idea what the specs were, but the shop selling them (you know, those dedicated speaker/amp shops that are relics of the past) were selling the crap out of them saying they were the best thing since sliced bread. So, I bought one. lol I can't remember what they were selling for, but they weren't cheap. I see US Audio Mart has an R700 "in box" for $225.00.

Note the "tuner." lol Time flies.