The Yamaha A-7xx series

Karl vd Berg

Super Member
Hi all,

For those who has/had/know about the following INTEGRATED models:

A-700 (1983)
A-720 (1985)
AX-700 (1986)

There are two of these models (A-700 and AX-700) available. Does anyone know any (sonic) difference between the 3 of them?

Thanks!
 
I bought an A-700 new. Still have it and still using it. Can't comment on the A-720 and AX-700.Very dependable and nice sounding integrated.
 
I bought an A-700 new. Still have it and still using it. Can't comment on the A-720 and AX-700.Very dependable and nice sounding integrated.
The A-700 is supposed to sound even "better" than the mighty CA-2010 according to AK member belgianbrain here. That's why I got real interest in this series and also because I've an A-520 which sounds incredible sweet to my ears.

There is an A-700 for 150 euros in good condition. And an AX-700 for 125 euros. Finally an A-720 for 175 euros.

Pretty tough actually!
 
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The A-700 is supposed to sound even "better" than the mighty CA-2010 according to AK member belgianbrain here.

I wouldn't be surprised. 80's gear is generally better than its 70's counterparts.

I only have experience with the AX-700, which was really great. A bit harsh on the ears, perhaps, and I couldn't quite feel the bass, but otherwise I liked it a great deal.

It looked really cool. And I miss it.
 
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I wouldn't be surprised. 80's gear is generally better than its 70's counterparts.

I only have experience with the AX-700, which was really great. A bit harsh on the ears, perhaps, and I couldn't quite feel the bass, but otherwise I liked it a great deal.

It looked really cool. And I miss it.
Thanks, Rool.

Your remarks match with what I found this morning on some Eastern communities: the 1986's AX-700 seems to be a bit harsh indeed. While the A-700 seems to have a very well balanced sound, the A-720 also would be harshier and lacking a bit of deep basses.

Very interesting the early and mid 1980s stuff. So far I have heard a few Integrated and I've been really surprised by the sound richness. :scratch2:
 
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I have an A-720, which I think sounds very good. I was not really expecting it to sound as good as it does, based on it's external appearance, but the looks were deceiving. To my ears Class A mode is an improvement over Class A/B. It has a few Blackgates inside, they appear to be original to the amp, Yamaha must have built them this way.

From pictures I have seen, internally the A-700 has more robust heat sinks. I don't know if this indicates a slightly higher build quality, or just a cost savings vs. the 720. I have not heard an A-700, so I can make no comparison there, but it would surprise me if it the sound is not quite similar. Without comparing two amps in similar condition, it would be difficult to make a realistic judgment, but you already know that.

Good luck picking out your amp, I hope you enjoy whichever one you end up with!
 
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I have an A-720, which I think sounds very good. I was not really expecting it to sound as good as it does, based on it's external appearance, but the looks were deceiving. To my ears Class A mode is an improvement over Class A/B. It has a few Blackgates inside, they appear to be original to the amp, Yamaha must have built them this way.

From pictures I have seen, internally the A-700 has more robust heat sinks. I don't know if this indicates a slightly higher build quality, or just a cost savings vs. the 720. I have not heard an A-700, so I can make no comparison there, but it would surprise me if it the sound is not quite similar. Without comparing two amps in similar condition, it would be difficult to make a realistic judgment, but you already know that.

Good luck picking out your amp, I hope you enjoy whichever one you end up with!

Thanks, 39cross!

I believe all the three models have pretty good performance. I'd lean on the A-720 model, I don't know why. But the A-700 is history.

I really like that series (up to mid 80s) from Yamaha... :thmbsp:
 
Karl, some more info for you, the A-720 has a couple of IC's in the phono stage but otherwise mostly if not all discrete components. Not sure if the phono IC's are used only for the MC input or not. There is (or was) a good review of the A-720 at the select45rpm.com website, but it's not available right now. This review helped convince me to buy mine.
 
Karl, some more info for you, the A-720 has a couple of IC's in the phono stage but otherwise mostly if not all discrete components. Not sure if the phono IC's are used only for the MC input or not. There is (or was) a good review of the A-720 at the select45rpm.com website, but it's not available right now. This review helped convince me to buy mine.
Yeah, I remember I read that review as well. They removed some of their links but it seems that the A-720 was the only 1980s' amp to "convince" them. A bit exaggerated maybe but still a good point in its favour. There are also the HK6950R and the Sony TA-F800ES (xxxxxx-rare pieces over here).

But that A-7xx series seems to be legendary! :thmbsp:
 
A-700

I bought one of these new back in the day along with Klipsch Heresy speakers. I used it exclusively for about 20 years before putting it into storage and going on an audio odyssey. About 6 months ago I pulled it out, deoxed it and cleaned it up-guess what? blows away some of my tube gear and new tranny amps-wonderful sound. I'm mostly running it in Class A and keeping it well ventilated. I'm using it with my old LaScalas which have brand new Crites cross-overs. It is a keeper. I hope I'm not jinxing it-but it is running with no issues. I bought it around 1983-4 plus or minus. I don't know how it compares with other Yamaha bec. I have'nt heard the other amps. It seems to have good quality build and parts. :tresbon:
 
A-700 vs. A-720

As AX-700 is gone...

I know it's gonna be a tough choice.

A-720 has this "Zero Distortion Rule" as my A-520 does.

ig7g.jpg


383e.jpg


Both are gorgeous!

But what also caught my attention is these Klipsch Heresy speakers you mentioned. A quick search online and it seems they are still being made IIUC... :scratch2:

Klipsch-1.jpg
 
Hey Karl, one other thing with the A-720 to let you know about. We had some problems with the Class A and Direct switches not working very well. I loaned my son, who has the amp for now (hooked up to some Monitor 10b's), my can of deoxit and it seems he must have fixed them for now.

I have advised him to make sure to run it in Class A this winter, it will help heat the apartment. He can also use it to cook eggs with. Yes, it does run that hot :)
 
Hey Karl, one other thing with the A-720 to let you know about. We had some problems with the Class A and Direct switches not working very well. I loaned my son, who has the amp for now (hooked up to some Monitor 10b's), my can of deoxit and it seems he must have fixed them for now.

I have advised him to make sure to run it in Class A this winter, it will help heat the apartment. He can also use it to cook eggs with. Yes, it does run that hot :)
39cross, I had the same problem with the A-520's Direct Souce switch.

And according to Dr.Cassette YT video (jump to about 2:15 till 4:45), might be a weak part in this series.

I used a whole can of Deoxit to get rid of a "clackling" noise everytime I pushed that buttom. And still...

I'm aware these little beasts run very hot, I have a couple of exotic fans waiting for one of them. :D

FANHA-304-10-wholesale-rayon-folding-hand-fans-wedding-fans-SV404285_c.jpg
 
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I have the ax 700.I completely re-capped all the electrolytics and absolutely love it.Beautiful sounding integrated amp to my ears.
 
I have the A700. Its been in the family since new. Lots of heavy use untill I retired it a few years ago.
Its is a heavy beast and built like a tank. Aside from cleaning dirty control, I only had two real problems.
First was an intermittent crackling noise. Turned out to be a break in a jumper on the PC board due to that TERRIBLE CORROSIVE GLUE!

Second is the POWER switch burned out. To keep using the amp, I bypassed it, still have not found a suitable replacement. I kept the switch anyway.

I was thinking of re-capping mine, but with that pair of 22K uf filter caps in the power supply it would probably be a little pricey.

Anyway if you think the price is ok and the amp works well, go for it.
 
How much did it cost you? What brand did you use, especially for the filters?


I ordered four 10,000uf Panasonic T-UP's for the main power caps to keep the cost down.They were around $10-$11.00 each. All other caps were a combo of of Nichicon KZ Muse,several Elna Silmic's,and Panasonic fc or fm. Very easy to do on this amp and I got it done in less than 2 hours.Sorry, but I don't remember the total cost of the capacitors.

After some burn in of the new caps I adjusted the idling current.The service manual states setting it around 10mv.It was running quite hot at that level so I lowered it down to around 5mv and have been good to go since.
 
A surprising (happy) ending here...

All the 3 models previously mentioned didn't have good selling negotiations at the end: two of them were sold and another went a bit over priced too me (~200 Euros)...

So, I found today an AX-900U from first owner, still with user's manual, all for 70 Euros (approximately $95). Well, I'm happy!

So far I've read only good reviews on this 1986 model and it seems it is pretty rare over here...

Yamaha-AX-900U.jpg


Yamaha-X-900U.jpg
 
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