YAMAHA A-S701 - tear-down, thoughts about the internals & few measurements

[TheBatsEar]

Yeah, the A-S801 (which is sadly not available in Australia) has an actual USB-B input, where as the lower models only have optical and coaxial.

I have one for sale in silver at Ebay Germany, but i guess shipping to Australia doesn't make sense.

Anyway, if any of you guys are into buying used and you want to buy an external DAC anyway and you want to have the power amplifier shared in the A-S700,701,801 and R-N803, search for the R-S700. It's the only one of the bunch with pre-out/main-in loop, which means you can loop in a DSP/EQ or split it up and use it as a pre-amp or power-amplifier if you update later. Pre-out/main-in loop can be added to the others as well, but you have to have a soldering iron and that's not everyones cup of tea.
They can be had for 200€ or less.

 

[NewbieAudiophileExpert]

I have one for sale in silver at Ebay Germany, but i guess shipping to Australia doesn't make sense.

Anyway, if any of you guys are into buying used and you want to buy an external DAC anyway and you want to have the power amplifier shared in the A-S700,701,801 and R-N803, search for the R-S700. It's the only one of the bunch with pre-out/main-in loop, which means you can loop in a DSP/EQ or split it up and use it as a pre-amp or power-amplifier if you update later. Pre-out/main-in loop can be added to the others as well, but you have to have a soldering iron and that's not everyones cup of tea.
They can be had for 200€ or less.

That's a good point actually - I've considered buying a new amp, but then I'd realised that even an older, used one worth more can be gotten for less.

Based on my understanding the amplifier technology is the same now as it was 40 years ago anyway.

I already have a Yamaha V6A and it works great for music, but I'm actively looking for a class AB stereo amp, 'just coz'.

 

[TheBatsEar]

That's a good point actually - I've considered buying a new amp, but then I'd realised that even an older, used one worth more can be gotten for less.
Based on my understanding the amplifier technology is the same now as it was 40 years ago anyway.

Yes, Yamaha uses the same design for decades, optimized a bit here and there, changed for different regulations and markets, but you can look into a Yamaha A-10 and a Yamaha R-N803 and see the same DNA. Right now Yamaha has, i think, three lines.

The cheap stuff: A-S201, R-S202, these have a tiny power supply and tiny heat sinks, they usually are designed for 8 ohm speakers only.

The solid stuff: A-S300 to R-N803. They share the same design, differences are in the sizing of the power supply, the amount of output transistors and heat sink. Even the small ones are ok. These can drive almost any speaker above 2 ohms. These have the variable loudness i think is a god send for apartment dwellers.

The heavy stuff, starting with the A-S1000 and up to their best power amps. This stuff has large power supply and large heat sinks and lots of output MOSFETs. The architecture is a bit different from what they did the last 40 years.

I already have a Yamaha V6A and it works great for music, but I'm actively looking for a class AB stereo amp, 'just coz'.

Well, you could get a A-S1000 for maybe 600€. If you never had a "high end" class device, this could be a good first one. I had two so far, both sold the same day i listed them at Ebay, they have good resale value, in case you don't want to keep it.

 

[nemanja_t]

I would skip A-S1000 and start with A-S2000 or A-S1100. Maybe it is easy to resell, but it is a hassle anyway. Better to buy a keeper.

 

[maty]

Amazon.de -> Germany and other EU countries as Spain: €640

YAMAHA A-S701 Stereo Integrated Amplifier with Built-In DAC, Silver

https://www.amazon.de/dp/B00MYDLL2C

 

[trl]

I found it on-sale at amazon.de back in 2018 at EUR 492,00. I find it a bit expensive right now, although I think it does deserve the money.

 

[Willem]

Prices have gone up since Covid.

 

[Willem]

I still bought an AS 501 for 359 euros for my daughter in late 2020. It has now gone up to 520 euros in the Netherlands.

 

[Zaratustra#31]

I bought a brand new A-S701 beginning of 2019 for 549€ in the Netherlands.

 

[TheBatsEar]

I bought a brand new A-S701 beginning of 2019 for 549€ in the Netherlands.

If you just need the A-S701 amp section, because you have a proper DAC, and are low on funds, consider a R-N700 and pay no more than 200€.
Same power supply and power amp section.

 

[trl]

Do you mean Yamaha R-S700? However, I think these are all EOL models and can't be actually found in the stores, right?

 

[TheBatsEar]

Do you mean Yamaha R-S700?

Yes, sorry.

However, I think these are all EOL models and can't be actually found in the stores, right?

Yes, you would have to buy used.

 

[HCT-5808]

I'm using the Rec Out on a Yamaha AS801 to feed an external headphone amplifier. Am I losing performance this way? Should I try to find an alternate way to feed this headphone amp?

 

[restorer-john]

I'm using the Rec Out on a Yamaha AS801 to feed an external headphone amplifier. Am I losing performance this way? Should I try to find an alternate way to feed this headphone amp?

The record outs on the AS-801 are swtiched through the input selection IC, which also contains some gain (to offset for losses) along with a capacitively coupled connection to the RCA (to prevent DC offset).

So, yes, you could be losing some performance, but you are gaining some useful switching. Are you using the onboard D/A, then looping out the rec outs into your headphone amplifier?

 

[HCT-5808]

The record outs on the AS-801 are swtiched through the input selection IC, which also contains some gain (to offset for losses) along with a capacitively coupled connection to the RCA (to prevent DC offset).

So, yes, you could be losing some performance, but you are gaining some useful switching. Are you using the onboard D/A, then looping out the rec outs into your headphone amplifier?

I'm using an inexpensive Topping outboard DAC (the inboard DAC does not handle switching sample rates gracefully) into the CD input of the Yamaha. Since the DAC only has a single RCA out, I'm using the REC OUT to go to the headphone amp. Wondering if I should invest in a DAC with more than one analog out.

 

[TheBatsEar]

I'm using an inexpensive Topping outboard DAC (the inboard DAC does not handle switching sample rates gracefully) into the CD input of the Yamaha. Since the DAC only has a single RCA out, I'm using the REC OUT to go to the headphone amp. Wondering if I should invest in a DAC with more than one analog out.

Why about an Y cable? I assume that should do the trick just fine.

 

[HCT-5808]

I think that would work. Don't know much about this, but would splitting the signal affect the voltage of the line level?

 

[Dirk]

On the first page of this thread it was mentioned that the volume control works digitally for the A-S701.
Does this refer to the mechanics of the volume knob or to the path of the audio signal?
The audio signal path of this amplifier should be fully analog, right?

 

[restorer-john]

On the first page of this thread it was mentioned that the volume control works digitally for the A-S701.
Does this refer to the mechanics of the volume knob or to the path of the audio signal?
The audio signal path of this amplifier should be fully analog, right?

It's complicated.

The volume control is an analogue potentiometer. In fact an Alps motorized potentiometer with twin gangs. It is not in the audio pathway at all. The volume knob and motorized position is all for show. Yamaha uses just one gang to provide a variable voltage level to an ADC (analogue to digital converter) which drives and controls the attenuator which is likely either a stepped resistor array or a VCA. All of it is under the control of a bespoke MCU derived from one of their obsolete AVRs. Nothing wrong with that, but it isn't some super pure 2 channel stereo amazingness they claim it to be.

Just today, I was repairing an A-S300 which uses exactly the same system (A-S300/301, 500/501, 700/701 etc).

Benefits are perfect channel tracking and smooth remote operation with music. Play test tones and hear the glitches in the stepping of the volume.
Relatively smooth source selection.

Downsides are very poor overload characteristics. 2.6V on a line input and the front end is done. Luckily 'most' sources are below that.

Does that help?

 

[ZolaIII]

@restorer-john most of the A-S and R-N line's have volume trim (±10 range) per input.
The amplifier section is not great regarding SINAD in low bass region but again volume trim also helps regarding that on regular 2V inputs to get it down to as mesured by Yamaha (500~600 mV) and recommended. The analog input line's should have been done better as there is lo level humm when you put your ear on the reasonably sensible speakers disregarding of the volume which isn't present when internal DAC is used rest is pretty much fine (not great or superb) regarding me.