The Yamaha A-7xx series

i have the yamaha a-700 very nice amp my gets a little hot after a while got some big heat sinks i think this is normal what do you think. paid 5 bucks at Salvation Army store what a deal

Wow! Thats a steal! Very good find!
 
Hi, thanks for your response. Do you think this amplifier is worth 150 bucks? Is this entry or mid fi yamaha during its time? If ever i pull the trigger on this, i will be using it to drive my 150 watts APM's. Thanks

See my previous quote:

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!
Now, some time after, I found another A-700 for 20 euros from someone willing to throw it away (picture above). But don't get me wrong: the A-700/A-750 is, for many, a legend and, considering the way it sounds, it worths more than $150. You'll never find a new amp in this same category for this price.

So, if you want to keep it and if it is in REALLY good conditions, then why not?

But... you can find an A-750/A-700 (not mine) for less if you not in a hurry. Sometimes they appear out of nowhere.
 
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!

Hi Karl, Soon I'll be able to give you an impression on the AX-700 you were originally looking at. I just bought one that I'll be giving to my daughter after looking it over. More info and pics as I get into it, should be here within a week.

Cheers,
James
 
:tresbon:
The AX-700 seems a very nice unit, James!
Waiting for the pictures! :thmbsp:

I've been very happy with my AX-1090 over the years and the AX-700 looked like a good match for the MB Quart 800 speakers that I was given, so I was very happy to get the amp for €84 at the auction site. These will all go to one of my daughters. As soon as I have more to share I'll post. The few photos of the amp interior that I've been able to find show a very nicely laid out interior.

Cheers,
James
 
The AX-700 arrived today and as promised here are a few pics. The seller did a reasonably good job of packing, double wall box, styrofoam, and lots of layers of bubble wrap, no styro-peanuts. Considering it's age the outside appearance is quite qood, a couple of very minor scratches on the front-top corners, and one larger (but not overly large) scratch on the left rear of the top.

Inside it's very dusty but has no signs of nicotine plating. I think that it will clean up quite nicely. There are no signs that anyone has ever been inside the amp in the past. All of the output transistors numbers match, as well as the few others that I checked in this first glimpse. Interesting to see that it uses the same A1265N & C3182N outputs as the A-1020, and the same quantity, but rated at 110 watts compared to the 125 watts of the A-1020. Does that mean that the AX-700 is throttled down in comparison or just conservitavely rated?

Sorry, but that's it for tonight. I was at the dentist this afternoon for the third part of a root canal handling that has gone somewhat sideways. And I'll be back in that same chair tomorrow morning at 8. I'm done in. But tomorrow I'll try to get some speakers and a cd player hooked up to it and give another report.

Cheers,
James

PS. It was a busy weekend here in Bratwurst Castle. I not only bought this AX-700 on Friday but also on Saturday bought a Yamaha T-700 tuner and an A-520 amp, both in black. They should be here by the end of the week.
 

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(...)

Interesting to see that it uses the same A1265N & C3182N outputs as the A-1020, and the same quantity, but rared at 110 watts compared to the 125 watts of the A-1020. Does that mean that the AX-700 is throttled down in comparison or just conservitavely rated?

...

Cheers,
James

4 pairs of outputs for 110W!! Awesome! Pretty sure the AX-700 sounds fantastic! Please, confirm it?

P.S.: Also in good condition! Did you check if the bias is ~10mV
SM: http://sportsbil.com/yamaha/tricomp_scans/AX700_AX700U_Speclayout.pdf (page 6)

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4 pairs of outputs for 110W!! Awesome! Pretty sure the AX-700 sounds fantastic! Please, confirm it?

P.S.: Also in good condition! Did you check if the bias is ~10mV
SM: http://sportsbil.com/yamaha/tricomp_scans/AX700_AX700U_Speclayout.pdf (page 6)

--

I found a service manual and the first thing that I'll do is check the idle current after a good dusting, followed with a headphone test. The only working speakers that are quickly at hand are a pair of little JBL Control 1X but I'll try them out. It will probably be the weekend before I can check it out with anything larger.

I'll take it out front and hook it up to my Speakerlabs then. I expect it to sound very similar to my AX-1090 and using the same speakers that I use with that amp will tell us a lot.

Cheers,
James
 
I was able to make the next step today. I turned on the amp and let it sit 10 minutes to warm up and checked the idle current. The left channel was quite high, almost 19mV so that got adjusted down. The right channel was dead on 10mV.

I closed it up temporarily and hooked up my little JBLs and headphones. I haven't done a deoxit yet, I wanted to check what it was like first. And it makes music! Good sounding music. Blues music actually. :music:

But I definetely need to do a thorough deoxit. Every switch and poti make some light scratching noises. And curiously when the volume knob is turned down all the way the left channel still plays very quietly. That's the only disturbing note, we'll see what it does after a good deoxit.

Cheers,
James
 

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Here are a few more photos for you Karl. The first on is the underside of the filter caps. Then a basic shot of the bottom to put it into perspective. The numbers are the best aproximation I could get with an old pair of calipers but they shouldn't be too far off. Then a nudie of the front. I've given everything a couple shots of deoxit and worked them around now. I'll do that again tomorrow.

Cheers,
James
 

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Like mine (AX-900), it looks a solid amp! Also nice and neat PCB. :thmbsp:

Mine had noisy pots and I used Kontakt 61 to clean them. However, CD Direct and Tone Bypass switches were still noisy when pushed and hard to get it fixed, unless opening it to clean inside. Kind of an issue similar to the great Harman Kardon PM665. I hope your unit is fine with the buttons!
 
Those 2 switches were noisy when I tested the amp yesterday. I hope that they don't give so much trouble that I have to open them, we'll find out in a day or 2.

James
 
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Today I finally took the AX-700 out front for a real trial run. Just 1 cd at this point, The Doobie Brothers Touloose Street. Mainly because I just listened to that cd yesterday through these speakers and my AX-1090.

And the "little" AX-700 is a champ. You could do a blind test with this cd/speaker combo and the 2 amps and I don't believe that one would be able to tell the difference. It handled driving the Speakerlab's 10+12" woofers with ease, although I do have to say that I didn't get into any real high volumes, but did get to a level where 2 people sitting next to each other had so speak up to talk to each other. Mid and high clarity is the typical clean Yamaha sound.

I'd say that the amp makes beautiful music. My daughter walked into the apartment while it was playing and is quite pleased with what she is going to get. And The T-720 tuner that she is going to get with it arrived in the post today, along with the A-520 that will soon be my PC/playroom/workshop amp.

Cheers,
James
 

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