Yamaha A-1 Vintage Amplifier Review

[restorer-john]

That was the time, when I first used attenuator cables with resitor-dividers in the RCA-plugs...owned a Yamaha A-960 for 35y.
Upgraded it a bit over the years, e.g. lower impedance input circuitry (10K Alps pot) and gained some 10dB of S/N since the double JFETs in the input were much better, than the resistor noise from the 100K volume pot...bought it for 1000DM in 1982 (510€) and sold it for 200€ around 2015...

An interesting amplifier for sure. Yamaha took some of the Carver ideas for the power supply (or vice versa- we'll never know).

I agree, if you came straight into the power amp, you'd likely have had a whole different beast. 35 years is an incredible run for a loyal amplifier!

A real mix of aesthetics- sliders and flush/flat front panels were on trend, but they couldn't alienate their knob twiddling audiophiles, so they left hangovers from the 70s with paddle selectors etc. In my opinion, Yamaha wallowed in a styling funk until late 1989/90 when the soft edges and all knobs made a return, along with clean panel lines with no jutting, angled 80s bits. Even the Centennial series was a styling mess (~1987).

 

[anmpr1]

One thing about the old 70s tuners that were good ones...they have fantastic FM receivers. The AM BCB in most of them was pedestrian...but the FM tuners were excellent.

Back then, if you were interested (and you had to be really interested) in AM, you could get one of the McKay-Dymek recievers, and run a wire out to your clothesline (that's a joke, I say that's a joke, son!) for reception. Those were probably the best the average consumer could buy for AM.

As I remember it, AM was mostly a car-oriented 45rpm Top 40-R&B-C/W thing (plus late night sports), all superseded by the rise of album oriented FM, but then came back with Rush and his gig. I can't remember the last time I wanted to tune in to an AM or FM broadcast station.

A quick search shows that McKay is still in business, but I didn't see any dedicated AM tuners. They do have this--a is pretty impressive wide band receiver (along with its pretty impressive 12.5K price tag). Makes Dick Sequerra's thing look sort of like a toy.

 

[eliash]

An interesting amplifier for sure. Yamaha took some of the Carver ideas for the power supply (or vice versa- we'll never know).

I agree, if you came straight into the power amp, you'd likely have had a whole different beast. 35 years is an incredible run for a loyal amplifier!

A real mix of aesthetics- sliders and flush/flat front panels were on trend, but they couldn't alienate their knob twiddling audiophiles, so they left hangovers from the 70s with paddle selectors etc. In my opinion, Yamaha wallowed in a styling funk until late 1989/90 when the soft edges and all knobs made a return, along with clean panel lines with no jutting, angled 80s bits. Even the Centennial series was a styling mess (~1987).

Yeah the design was not so consistent, but the sound was always flawless. Actually the young guy who bought it was somehow linked into designing things, he really liked it. Anyway, gone and never heard about it again, even though I offered technical assistence if ever needed...so approaching 40y of service.
...Seems to be some kind of time lag involved, probably he got used to that kind of design when being young.
Me grew up with the Braun design of my fathers "Snow White coffin" integrated TT/receiver. That is probably the reason, why I had to have one of the last T+A R-1xx0 series pre/post amps afterwards, when discontinued...

 

[Willem]

Don't remind me of the brilliant designs by Dieter Rams for Braun. Never in history was any audio as beautiful as those.

 

[eliash]

Back then, if you were interested (and you had to be really interested) in AM, you could get one of the McKay-Dymek recievers, and run a wire out to your clothesline (that's a joke, I say that's a joke, son!) for reception. Those were probably the best the average consumer could buy for AM.

As I remember it, AM was mostly a car-oriented 45rpm Top 40-R&B-C/W thing (plus late night sports), all superseded by the rise of album oriented FM, but then came back with Rush and his gig. I can't remember the last time I wanted to tune in to an AM or FM broadcast station.

A quick search shows that McKay is still in business, but I didn't see any dedicated AM tuners. They do have this--a is pretty impressive wide band receiver (along with its pretty impressive 12.5K price tag). Makes Dick Sequerra's thing look sort of like a toy.

View attachment 37334

This can probably still be topped by the audio reproduction (at least w external speaker) of Lowe´s HF150 receiver in double-sideband wide-AM mode.
...Unfortunately no public AM transmitted from Germany any more, neither long, medium nor short wave, no reason to pack it for long distance travel any more...

 

[cistercian]

Back then, if you were interested (and you had to be really interested) in AM, you could get one of the McKay-Dymek recievers, and run a wire out to your clothesline (that's a joke, I say that's a joke, son!) for reception. Those were probably the best the average consumer could buy for AM.

As I remember it, AM was mostly a car-oriented 45rpm Top 40-R&B-C/W thing (plus late night sports), all superseded by the rise of album oriented FM, but then came back with Rush and his gig. I can't remember the last time I wanted to tune in to an AM or FM broadcast station.

A quick search shows that McKay is still in business, but I didn't see any dedicated AM tuners. They do have this--a is pretty impressive wide band receiver (along with its pretty impressive 12.5K price tag). Makes Dick Sequerra's thing look sort of like a toy.

View attachment 37334
That is the monster Icom receiver the IC-9500. It is epic. I have a R-8500 which is very nice but my
Icom 7410 and 9100 blow it away on HF and AM BCB...filter width is adjustable in the DSP
and sound quality is great via Sennheiser HD600 phones. When I was a boy I used a Zenith trans-oceanic
tube rig...it had a detachable am loop you could move around for best S/N. It was a tube radio
and very strong on the AM BCB.

 

[restorer-john]

Yeah the design was not so consistent, but the sound was always flawless.

They were very good amplifiers alright.

 

[LTig]

This can probably still be topped by the audio reproduction (at least w external speaker) of Lowe´s HF150 receiver in double-sideband wide-AM mode.
...Unfortunately no public AM transmitted from Germany any more, neither long, medium nor short wave, no reason to pack it for long distance travel any more...
View attachment 37347

Same problem with this nice receiver:

But I can listen to amateur radio stations (here in the 80m band), with an active magnetic antenna (Wellbrook) of 1m diameter indoor (not shown).

 

[restorer-john]

Same problem with this nice receiver:

We all know that when the big one (asteroid/comet whatever) hits, the only transmissions from pockets of survivors around the world cowering in disused tunnels will come via AM/SW/LW etc. Us old coots with communications receivers will be able to hear (but not talk back...)

 

[RickSanchez]

I liked Harmon-Kardon amplifiers in the mid 80's. I had an HK870 amplifier and thought it sounded pretty good. However, I'm not sure how it measured.

Reading Amir's review on this A-1 got me to do some research on my own Harman/Kardon hk670. (I threw my findings up here: https://www.audiosciencereview.com/...ceiver-amplifier-stereo-review-apr-1979.9639/)

The fun discovery for me was coming across AmericanRadioHistory.com and all of their back issues of Stereo Review magazine. I'm in no way qualified to talk about Julian Hirsch, Hirsch-Houck Laboratories, the testing equipment they used, or how it compares to Amir's equipment + testing process. But my point is that there are some measurements out there for older equipment. It's limited for sure, but worth doing a little digging.

And while I'd love to send my hk670 into Amir for measurement that's a bit beyond my budget at the moment ...

 

[amirm]

And while I'd love to send my hk670 into Amir for measurement that's a bit beyond my budget at the moment ...

You can start a new thread and see if we can get enough people to offset the cost of shipping.

 

[RickSanchez]

You can start a new thread and see if we can get enough people to offset the cost of shipping.

Good idea! I’ll ask on the hk670 thread I posted earlier.

 

[cjfrbw]

I only have gone through half the thread, but yeah, those old Yamahas were built. I still have my all original (cleaned and re-biased once) Yamaha B2 that I have been using routinely for over eight years on my bass panel. It must be at least forty years old now.

I have a spare amp to put in it's place whenever it breaks, but it is still going strong. It sounds so wonderful when I play it full range, that if you told me fully functioning Yamaha B2 were the only amplifiers that I could ever own any more, I would never feel deprived. Whenever I play it full range, it keeps me completely entranced and hypnotized about what is coming next in the musical agenda, and the needle seldom indicates power levels over 5-10 watts.

 

[amirm]

The owner said the phono stage has a reputation of excellence so wanted to see its measurements. Here they are:

Managing ground loops is quite complex here. There are so many variations impacting both baseline noise and mains noise. The above was one of better scenarios. There is no distortion to worry about. All you have is the mains noise.

FYI the "DISC" mode made the above worse so I did not bother using it from here on.

Frequency response measurement was nicely flat in audible band:

Distortion and noise relative to input level is also very good:

As is THD+N versus frequency:

I developed a new test to see how fast the input recovers from an overload condition. A burst sine wave is used where its amplitude toggles from 0.1 volt to -80 dB below it. The 0.1 volt should cause the phono stage to saturate well and then we can watch how long it takes it to drop back down:

EDIT: ignore this measurement. It was setup incorrectly. Work in progress.

I will have to run this test on other products to get a good idea of whether this is typical, good or bad. Feedback on this test is appreciated.

That's it really. Seems like a well executed phono stage given the constraints of mains leakage we are dealing with in these measurements.

 

[Blumlein 88]

The owner said the phono stage has a reputation of excellence so wanted to see its measurements. Here they are:
View attachment 37495

Managing ground loops is quite complex here. There are so many variations impacting both baseline noise and mains noise. The above was one of better scenarios. There is no distortion to worry about. All you have is the mains noise.

FYI the "DISC" mode made the above worse so I did not bother using it from here on.

Frequency response measurement was nicely flat in audible band:

View attachment 37496

Distortion and noise relative to input level is also very good:

View attachment 37497

As is THD+N versus frequency:

View attachment 37498

I developed a new test to see how fast the input recovers from an overload condition. A burst sine wave is used where its amplitude toggles from 0.1 volt to -80 dB below it. The 0.1 volt should cause the phono stage to saturate well and then we can watch how long it takes it to drop back down:
View attachment 37499

I will have to run this test on other products to get a good idea of whether this is typical, good or bad. Feedback on this test is appreciated.

That's it really. Seems like a well executed phono stage given the constraints of mains leakage we are dealing with in these measurements.

Can you supply a graph of the input on the burst sine wave so we can compare it to the output. Just to be clear on how the burst is being handled.

 

[amirm]

Actually ignore that measurement. I had forgotten to uncheck the box so it was measuring the AP itself! Anyway, here is the generator panel:

You can see the input sinewave in the graph.

 

[restorer-john]

Feedback on this test is appreciated.

If you are attempting to determine overload characteristics and recovery, the normal procedure would be to wind up the input level until the input stage clips, take a voltage measurement and express it as dB (or mV) over and above the rated sensitivity for rated output.

Why you would be using 10Hz for a phono stage that will roll off well above that, is also a mystery to me. 1KHz maybe.

As for overload recovery, it's not like an amplifier where the type of attached load will affect the overload recovery time or characteristics. It's also not subject to power supply fluctuations like a power amplifier as the front end is fully regulated. Such an extreme input into a front end that results in the practically square wave depicted above is not really useful in my opinion.

 

[eliash]

Same problem with this nice receiver:

View attachment 37403

But I can listen to amateur radio stations (here in the 80m band), with an active magnetic antenna (Wellbrook) of 1m diameter indoor (not shown).

Actually I owned the same for short wave listening, a great receiver! Used it with a homemade active antenna in the 90´s in an apartmentment building (antenna with cantilever on the balcony, handrail as ground) - lot´s of fun!
Fortunately the public interest in such devices was still high enough at the end of the millenium...

 

[AudioSceptic]

I only have gone through half the thread, but yeah, those old Yamahas were built. I still have my all original (cleaned and re-biased once) Yamaha B2 that I have been using routinely for over eight years on my bass panel. It must be at least forty years old now.

I have a spare amp to put in it's place whenever it breaks, but it is still going strong. It sounds so wonderful when I play it full range, that if you told me fully functioning Yamaha B2 were the only amplifiers that I could ever own any more, I would never feel deprived. Whenever I play it full range, it keeps me completely entranced and hypnotized about what is coming next in the musical agenda, and the needle seldom indicates power levels over 5-10 watts.

So, why not use it full range permanently?

 

[cjfrbw]

So, why not use it full range permanently?

I have active crossover with panels and surrounds. I use several amps for the different ribbons. I do listen to the B2 full range through one panel sometimes, but the full array with active crossovers and amps for the different ribbons with surrounds overall sounds better than even the B2 by itself on a single panel.