Yamaha A-S701 Stereo Amplifier Review

[Overseas]

Try 'Inside Yamaha amps' https://www.audiosciencereview.com/forum/index.php?threads/inside-yamaha-amps.21894/

 

[antcollinet]

My Yamaha A-S2100 has an issue in the last time: After a hour of playing on decent levels, the amp switches off due to trigger of protection circuit.
Then I have done som research because of this behavior: the LED above the power switch is indicating the kind of error: Thermal overheating!
But that couldn’t be true. The amp goes only hand warm. The impedance of my speakers are also not a real problem: ProAc Tablette 10 Signature has 10 Ohm nominal impedance.
So there must be a problem with the temperature sensing in the device.
Any ideas what could be done in this case?

What is your definition of "decent level", at what listening distance, in what sized room, at what ambient temperature. (If you have an iphone you can use a phone app to measure the SPL of whatever you are listening to).

 

[Ruediger]

Is there enough airflow? It usually means there has to be enough space around and above the unit. The manual might have min. numbers.

The sensor won't be attached to the top lid, where we touch to get a sense of the temperature.

I used to have a 3010 in a rather small rack. It got pretty hot but never shut down. I would also check the speaker cables and connections.

 

[ptrg]

I just wish it had 12v trigger

I used to have similar problem with A-S 700 Amp. I bought trigger module from small Polish company Matway Electronics. You plug the module into power port of the amp and then power cable into the module. In my case the module is connected with Wiim Ultra's trigger out. It works perfectly, I never had to bend down to on/off switch again

 

[Ruediger]

Smart little product.

I saw something alike on amazon. Haven't compared prices.

VOCOMO Trigger Switching Socket V1 (3680W) for AV Amplifier / Receiver Trigger, Standby Killer Adaptor Plug : Amazon.de: Electronics & Photo

VOCOMO Trigger Switching Socket V1 (3680W) for AV Amplifier / Receiver Trigger, Standby Killer Adaptor Plug : Amazon.de: Electronics & Photo

www.amazon.de

 

[EXIF68]

What is your definition of "decent level", at what listening distance, in what sized room, at what ambient temperature. (If you have an iphone you can use a phone app to measure the SPL of whatever you are listening to).

Decent Level is low level. I would say something about 80dba.

 

[wwenze]

Just picked up an open box Yamaha as501 at a very good price and what can I say, it’s great. I didn’t have to spend a ton of money and it should last me through any future speaker upgrades. I just wish it had 12v trigger in and quicker auto standby, I’ve been spoiled by a wiim pro plus + topping and Fosi. But I was looking for an all in one integrated amp with phono, trying to eliminate so many boxes and cables. This thing is chunky but I do love the look of it and blends in nicely with the rest of my system. Price to performance I am very happy with it

S501 is measurably transparent to the ears too, but S701 is a different level of measurement so now you have something to look forward to.

 

[BlueMax]

I would say that the biggest difference between A-S501 and A-S701 is not the difference in power but that the former does not have a CD Direct feature, which means that all line inputs on the 501 are the same and there isn’t a special one with a better performance. Having said that, I’m aware of measurable differences between line inputs and CD input with CD direct feature engaged on the A-S701, but I have yet to understand how it translates into any audible differences.

Perhaps easiest way is to plug in a good source (CD player, DAC, streamer) into the CD input on the 701 and try to hear the difference between CD Direct feature turned on and off. I’m still waiting for my 701 that I’ve just purchased, so this will probably be the first experiment that I will try when it arrives.

Also, hello to everyone as this is my first post here

 

[antcollinet]

I would say that the biggest difference between A-S501 and A-S701 is not the difference in power but that the former does not have a CD Direct feature, which means that all line inputs on the 501 are the same and there isn’t a special one with a better performance. Having said that, I’m aware of measurable differences between line inputs and CD input with CD direct feature engaged on the A-S701, but I have yet to understand how it translates into any audible differences.

Perhaps easiest way is to plug in a good source (CD player, DAC, streamer) into the CD input on the 701 and try to hear the difference between CD Direct feature turned on and off. I’m still waiting for my 701 that I’ve just purchased, so this will probably be the first experiment that I will try when it arrives.

Also, hello to everyone as this is my first post here

Welcome to the forum.

I suspect when you try your experiment you will hear no difference. If you do hear a difference, then you will need to repeat the test blind (have someone else perform the switching - in a way they can't unconsciously signal to you what they are doing) to eliminate your perceptive biases as being the cause, rather than any real sound quality difference.

IOW - CD Direct is very unlikely to make an audible difference in real world listening.


EDIT : Where have you seen measured results from CD Direct? I've been unable to find any.

 

[respice finem]

Yamaha AS-501 has a "pure direct" switch, even the cheaper AS-301 does.

A-S501 - Overview - Yamaha - United States

Impressive high quality sound with a wide range of features and an elegant appearance. An integrated amplifier with the advantage of digital inputs.

usa.yamaha.com

A-S301 - Overview - Yamaha USA

Designed for excellent sound quality, with a beautiful appearance. An integrated amplifier with the advantage of digital inputs.

usa.yamaha.com

 

[Ruediger]

I would say that the biggest difference between A-S501 and A-S701 is not the difference in power but that the former does not have a CD Direct feature, which means that all line inputs on the 501 are the same and there isn’t a special one with a better performance. Having said that, I’m aware of measurable differences between line inputs and CD input with CD direct feature engaged on the A-S701, but I have yet to understand how it translates into any audible differences.

By concept CD direct is meant to provide a more direct signal path. Maybe disabling some things like bass/treble/balance knobs. My 301 doesn't have that.

All these amps have pure direct! It doesn't get better than that for analogue sources.

 

[Willem]

By concept CD direct is meant to provide a more direct signal path. Maybe disabling some things like bass/treble/balance knobs. My 301 doesn't have that.

All these amps have pure direct! It doesn't get better than that for analogue sources.

But don't scorn the benefits of the variable loudness. Those benefits are far bigger than the tiny measured benefits from the direct path.

 

[antcollinet]

But don't scorn the benefits of the variable loudness. Those benefits are far bigger than the tiny measured benefits from the direct path.

This. Tone controls also are not the bogeyman the world of audiophillia will tell you they are.

 

[BlueMax]

Yamaha AS-501 has a "pure direct" switch, even the cheaper AS-301 does.

A-S501 - Overview - Yamaha - United States

Impressive high quality sound with a wide range of features and an elegant appearance. An integrated amplifier with the advantage of digital inputs.

usa.yamaha.com

A-S301 - Overview - Yamaha USA

Designed for excellent sound quality, with a beautiful appearance. An integrated amplifier with the advantage of digital inputs.

usa.yamaha.com

However, as I understand it, Pure Direct and CD direct features are two different things. Pure Direct probably bypasses tone, balance and loudness controls whereas CD direct bypasses some/most of the digital circuits. If those two were the same, it wouldn’t have been the case that the 701 has both features.

 

[Sokel]

Control knobs bad reputation comes straight from the use of bad quality ones, susceptible to imbalances, open to dirt and corrosion, etc.
NOT the case with the Yamaha ones, they are usually more than decent.

(their feel is also an almost forgotten art, it's a joy to use them)

 

[Ruediger]

The tone controls on these Yamaha amps work well from what I have experienced.

Yamaha doesn't tell us much, but CD direct could be "direct" here (knob function preserved) whereas pure direct is "bypass all". Both bypass adc of course.

 

[BlueMax]

Welcome to the forum.

I suspect when you try your experiment you will hear no difference. If you do hear a difference, then you will need to repeat the test blind (have someone else perform the switching - in a way they can't unconsciously signal to you what they are doing) to eliminate your perceptive biases as being the cause, rather than any real sound quality difference.

IOW - CD Direct is very unlikely to make an audible difference in real world listening.


EDIT : Where have you seen measured results from CD Direct? I've been unable to find any.

I think I saw it in some of the tests of Yamaha gear in Polish Audio magazine, but now I only managed to find measurements of the A-S700 that were done with both Direct features engaged and not engaged.

“The signal-to-noise ratio is 90 dB, the dynamic range is 111 dB, but by not engaging both Direct modes, we will get results that are 4 dB worse.”

YAMAHA CD-S700 + SA-700

Sukces systemu 2000 nie pozostawiał niedomówień - audiofilskie stereo znajduje uznanie i nabywców. Yamaha idzie za ciosem, ale tymczasem ...

audio.com.pl

I’m sure there are measurable differences between the modes in A-S701 just as well. Only question is how they translate into anything that could be described as potentially audible. From your responses I get it is unlikely that I will hear any differences, which is a good news to me since I have more than one source that I would like to plug into the line inputs on my new A-S701.

If the sound was indeed worse using those line inputs rather than CD direct, then I would only use my WiiM Ultra as a digital hub for my other sources (Yamaha CD-S303, Oppo BDP-105D and TV) and I would plug the WiiM into CD input on the 701 with both Direct modes engaged.

 

[Randolf]

According to the Block Diagram of the A-S701 service manual, Pure Direct bypassses the tone controls. CD Direct converts the unbalanced CD input signal to balanced and passes it to the the volume control of Rohm BD3473KS2 (bypassing tone control and loudness) and converts it back to balanced before passing it to the 29db gain main amp (red: CD direct, green: Pure Direct):

Both improve the SNR, CD Direct even more, according to spec in the service manual:

Signal to Noise Ratio (IHF-A Network)
CD, etc (Pure DIRECT ON) (200mv Input shorted) 99dB or more
CD DIRECT ON 104dB or more

Yamaha is using this type of bypassing since decades. My experience with that is the residual noise is reduced which could become audible with high sensitivy speakers or nearfield listening. The already rather low hiss is further reduced.

 

[Multicore]

"Direct" and "defeat" switches are like the "door close" button in elevators/lifts.

 

[antcollinet]

“The signal-to-noise ratio is 90 dB, the dynamic range is 111 dB, but by not engaging both Direct modes, we will get results that are 4 dB worse.”

That is about what I might expect. You will not hear the difference between 90 and 86dB SNR, nor 111 vs 107dB.

IMO.