Yamaha A-S701 Stereo Amplifier Review

[WillBrink]

Useful review. I do wonder if there's further improvements to measurements as you go up the food chain of their integrated amps, or just paying for thicker face plates, nicer knobs, etc.

 

[ralph]

Great review @amirm, thanks!

Can anyone comment on the usefulness of loudness - pardon me for the question - I know that this contradicts with the ideal of an amp not to mess around with the input signal ...

 

[Sokel]

Great review @amirm, thanks!

Can anyone comment on the usefulness of loudness - pardon me for the question - I know that this contradicts with the ideal of an amp not to mess around with the input signal ...

Not messing around with the input signal means also true to level intended for playback,most times unknown and many-many other things.
I wouldn't worry about loudness if that makes you listen to more music.

 

[Timcognito]

Without speaking to how it is implemented on the AS701, the loudness feature is used to boost or reduce bass frequencies, generally boosting bass for low level listening where the demands of a woofer exceed amplifiers delivered power.

 

[Doodski]

Great review @amirm, thanks!

Can anyone comment on the usefulness of loudness - pardon me for the question - I know that this contradicts with the ideal of an amp not to mess around with the input signal ...

Tone controls, bass and treble controls, EQ and PEQ are all very valuable tools that greatly enhance the listening experience. Don't fall for that straight wire is best idea because in this case the benefits of the variable loudness control with the Yamaha far outweigh any benefit gained by not including them in the unit.

EQ Software for Windows, Linux, macOS, iOS/iPadOS and Android.

Any suggestions are welcome. Post suggestions here. I will gather the details and add them. Thanks. :D This will be organized as results come in. @sweetchaos made a guide for PEQ filter data input and operation. For crossover software go here. Windows: AutoEQ four easy steps to make your...

www.audiosciencereview.com

 

[phoenixsong]

I just realized the older A-S700 model actually has better published specs

 

[amirm]

Did the older one have a DAC?

 

[caioferrari]

Did the older one have a DAC?

No.

 

[caioferrari]

Useful review. I do wonder if there's further improvements to measurements as you go up the food chain of their integrated amps, or just paying for thicker face plates, nicer knobs, etc.

That’s a nice question.
Probably there is some improvements that are not audible…

 

[diddley]

Thank you Amir for this review, i do like it when intergrated amps are reviewed.

 

[ZolaIII]

Did the older one have a DAC?

Yamaha A-S701 Stereo Amplifier Review

I just love the silver Yamaha design and just booted out an old black Rotel CD-player for a CD-S300 for that single reason. Optical out only of course. This member of the Yamaha Fan Club says thanks for the review. I like others would have liked to see measurements of DAC and Phono performance...

www.audiosciencereview.com

SINAD whose about 95~96 dB as much as I remember.
Edit: best unbalanced analog input regarding SNR Yamaha has up to today which rivals and some of competitors balanced ones. On older and earlier discontinued R-S700 it's 106 dB thanks to analog tuner, sadly they don't put that old property unbalanced analog input on any of newer more budget oriented models. Now it can be found only on higher A-S (1000+) lines which also have balanced inputs and little better crosstalk (thanks to better typology) but I don't think you really need it.

 

[amirm]

No.

The addition of digital circuits for that may have degraded performance a bit.

 

[Multicore]

One thing that's missing that was common on the old-timey amps this model reminds us of is the mono button. I still find that very useful, there being so many recordings with stereo mixes that sound better down-mixed.

 

[mc.god]

Frequency response is nice and flat in audible band:
View attachment 375872

For kicks, I tested the loudness response as you see above. I have never used an amp with variable loudness. The ones with switches made things louder, not less loud.

My old Denon PRA-1500 has variable loudness and it behaves in the same way. The more you turn it up boosting highs and lows, the more it applies negative gain according to some type of compensation curve, more or less like we do with PEQ.
For "classic" tone boosting it has standard tone controls.

 

[PuX]

It was offered from 1998 thru 2001 and cost US $399. That is not budget pricing for a 40 Watt /ch amplifier at that time.

NAD has many variations of similar design, C352, C355, C356, C375.
all kinds of power levels and all very reasonably priced and available for a long time, at least 2015 or even later.

in any case an amp from 26 years ago performs same as one from today and somehow the one from today is considered good to great? where's the progress?

 

[carsknivesbeer]

As an owner of refurbished a-s501 and a-s701 going strong after years and years (a-s700 and ca-2010 too...) the straightforward design of the Yamahas has always had a sweet spot in my heart. They seem to deliver a good value for their price and it's nice to see some actual measurements. The headphone amp and phono stage are mediocre at best and imagine they don't measure well at all. No issues so far and it is nice to a relatively dumb receiver still available without being cluttered with bluetooth and things that will break or become obsolete before the amp does while making the signal chain worse.

Maybe we can see the matching CD-s30x cd player measurements next...

 

[restorer-john]

Could be great if you can measure the phono input too.

The phono input circuitry is basically the same across the range from 300/301/500/501/700/701.

A-S701 phono stage:

The big issue of course is the overload characteristics due to the 5V supply rails and the following AVR chipset input limitation issues. The 701 phono overload is rated at 45mV (or more), which is absolutely atrocious. I tested the 300/301 -same circuitry but with much higher rails for the phono stage:

A-S300/301 phono stage (note the higher supply rails on the same circut):

It overloaded a 74mV@1kHz, which was dead last in a test of a dozen phono stages. To put in perspective, that is about half what even a cheap 1970s integrated would offer.

That said, the phono stage was very quiet (low noise) and sounded OK.

The entire range is built around 1990s Yamaha TopArt amplifiers (which is good), they've strapped on a cheapish D/A, used AVR chips for all the switching/routing and electronic volume (the volume pot is an input device to an A/D in the chipset) and run the entire thing from a custom uP.

They are great value and work well, but they aren't SOTA. You really have to step up further along Yamaha's range to get something special.

 

[audiofooled]

Keep in mind that these are stereo tests so total power is twice as much. Very nice.

I should note that the amplifier handled overloads during this test as if they were not there. No protection. No powering down. No nothing

I voted Great because of this. Call it a bias, but my Yamaha DSP A-1000 is 33 years old and still going strong. Overloads are nothing, protection is tripped only in case of thunderstorms and lightning strikes.

 

[Doodski]

an amp from 26 years ago performs same as one from today and somehow the one from today is considered good to great? where's the progress?

If we are discussing a Yamaha amp/receiver as long as it is a ToP-ART Series design they are all very similar from then to now because it is such a successful series.

 

[restorer-john]

If we are discussing a Yamaha amp/receiver as long as it is a ToP-ART Series design they are all very similar from then to now because it is such a successful series.

Yamaha had to do something in 1988-90 with their amplifier design as it was still languishing in the 1970s. I remember the fanfare of ToP-ART. Big product nights and many oohs and aahs when we peered inside.

Fact was, Yamaha amps prior to ToP-ART were lacking and Pioneer/Sony etc had leapfrogged them in design and performance. Their physical appearance prior was a real mess of bad 1980s angles/flat buttons/silly fonts etc. They did a good job and we still have that Yamaha legacy 35 years later. They have however stripped out some of the good stuff. The HCA circuitry is sadly gone, as are proper adjustments for bias on the production line. They just snip a resistor or leave it- near enough is good enough these days. And these putrid AVR chipsets do nothing useful other than save a ton of money and diminish performance. The only positive is perfect channel balance across the volume range.

This is the block diagram of the A-S701:

The CD direct button is hardly direct. It bypasses the input selector, but is still subject to the overload issues of the main AVR chip. So they take an unbalanced SE signal, make it "differential" to use two channel inputs, process it and convert back to SE before amplifying. Notice all the markings for the AVR IC channel designations they are using...