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

[ZolaIII]

That's quite a balanced review, and focuses on the key feature for me being the room correction. I wonder if you can switch it out for headphones (and use a separate PEQ for them)

Wouldn't use headphone out from any power amplifier which doesn't have deticate headphones amplifier anyway. I added that url mostly for the inside pictures and of course it's useful reading getting to know basic functionality.

 

[Bernard23]

I sometimes plug in a cheap pair of Yamahas just to be in the same room as the family, otherwise a dedicated dac amp in my office.

 

[Bernard23]

I'm continuing my search of all things Yamaha amplification, and stumbled across this post, from 9 years ago. I wonder, is this still your opinion @restorer-john?!

 

[TheBatsEar]

I'm continuing my search of all things Yamaha amplification, and stumbled across this post, from 9 years ago. I wonder, is this still your opinion @restorer-john?!View attachment 334208

Well.
He was right about everything, except longevity. @restorer-john was young and naive then.

There is a quote from https://en.wikipedia.org/wiki/Willy_Brandt he said to a journalist asking about something he said a few years ago: "Was interessiert mich mein Geschwätz von gestern."
Maybe you could translate it to "What do i care about my wish-wash from yesterday."

I think the devices have shown that they are as good as the old style stuff. There are countless A-S1000 out there almost 20 years old without any problems, despite micro controllers and SMD components.

 

[Deleted member 48726]

Well.
He was right about everything, except longevity. @restorer-john was young and naive then.

I don't know man, was he ever young?

I think the devices have shown that they are as good as the old style stuff. There are countless A-S1000 out there almost 20 years old without any problems, despite micro controllers and SMD components.

They are for sure. I think if one has to point to something, and that may also have been John's point, is that if or when the micro-controller a SMD goes out, it is not trivial to repair. Also a fault from a micro-controller may be non-logical making it hard to troubleshoot.

BUT I think it is worrying without much reason. I mean I can buy a used AVR for what amounts to four pizzas and there is a sh**load of them for sale. They all have micro-processors and many of them are old.

 

[Bernard23]

I have an option to part ex my S-501for a 2011 vintage A-S1000 for around £200, good move?

 

[trl]

As per specs, the A-S1000 is better in every aspect, including design and look & feel. Not sure who would like to trade the A-S1000 for an A-S501, but if you really trust the seller and you're confident that all inside components are original then go for it. If the no. of power on hours was not very high, then I think that its age of 13 years should not matter so much.

 

[Deleted member 48726]

I have an option to part ex my S-501for a 2011 vintage A-S1000 for around £200, good move?

Let me understand; do you have to pay 200 pounds and the A-S501 in exchange for the A-S1000?
If yes then I don't think you get your moneys worth and certainly not more power or audibly better sound. The two have in practice the same power output both dynamically and continuously.

You would get a unit with arguably better internal components and design. Is that worth it? -You decide.

 

[trl]

Let me understand; do you have to pay 2000 pounds and the A-S501 in exchange for the A-S1000?
[...]

I see 200 GBP wirrten up there, so I would say it's a very good trade if the A-S1000 is in perfect condition and without electronic parts damaged (swollen caps etc.) or any unauthorised interventions (transistors changed with Aliexpress fakes etc.).

 

[Deleted member 48726]

I see 200 GBP wirrten up there, so I would say it's a very good trade if the A-S1000 is in perfect condition and without electronic parts damaged (swollen caps etc.) or any unauthorised interventions (transistors changed with Aliexpress fakes etc.).

Subjectively, looking at launch prices, internal design, materials etc. it may be a good trade for the individual.

Objectively, just looking at the specs. it is not though.

 

[Extreme_Boky]

I would never dare buy an amplifier with uPC inside. Once the part is gone, you end up owing an expensive door-stopper. And I know a fair few cases where the owners had to say goodbye to their expensive amps because the manufacturers ran out of microprocessors/spares. Trying to bypass the microprocessor-controlled functionality in the hope of at least salvaging the amplifier section, is not an easy task, even for a well-experienced and perisitant/determined engineer/ DIY-er.

 

[Deleted member 48726]

I would never dare buy an amplifier with uPC inside. Once the part is gone, you end up owing an expensive door-stopper. And I know a fair few cases where the owners had to say goodbye to their expensive amps because the manufacturers ran out of microprocessors/spares. Trying to bypass the microprocessor-controlled functionality in the hope of at least salvaging the amplifier section, is not an easy task, even for a well-experienced and perisitant/determined engineer/ DIY-er.


View attachment 340014

Yeah. Fear and doubt. I, on the other hand, have never heard of these cases.
If, and only if, it was an actual problem with chips dying, I'd agree with you. But I don't see the problem.

 

[Joe Smith]

I think I've decided that an AS-501 is in my future for later this year, to be my new main integrated amp downstairs, where I need about that level of power and a phono circuit, plus digital inputs. For about $450, there's nothing I can find that's as good an all-round solution. My Kenwood KA-3500 that I had in that spot developed a problem, which has turned out to be a fairly expensive diagnostic with my local friend/tech. I think it's probably time to cut my losses on that one. I plan to sell a lot of my older amps and receivers locally over next summer, I'm ready to move on from the older equipment for the most part.

Onkyo seems to have two new integrateds coming out this spring but their power is low compared to the Yamaha lineup, and the prices are higher. The ~$600 one is only spec'd for 60 wpc at 4 ohms.

 

[Bernard23]

Let me understand; do you have to pay 200 pounds and the A-S501 in exchange for the A-S1000?
If yes then I don't think you get your moneys worth and certainly not more power or audibly better sound. The two have in practice the same power output both dynamically and continuously.

You would get a unit with arguably better internal components and design. Is that worth it? -You decide.

Thank you, I'm not convinced either, just tempted by looks and a few random comments that the xx00 amps are a whole different league better than the x01 range. I'll keep the 501 and keep looking for an 803D with its YPAO.

 

[trl]

I would never dare buy an amplifier with uPC inside. Once the part is gone, you end up owing an expensive door-stopper. And I know a fair few cases where the owners had to say goodbye to their expensive amps because the manufacturers ran out of microprocessors/spares. Trying to bypass the microprocessor-controlled functionality in the hope of at least salvaging the amplifier section, is not an easy task, even for a well-experienced and perisitant/determined engineer/ DIY-er.

Most AV consumer manufacturers are using their own MCUs these days. However, are you having some other models in mind to recommend, something new but easy to service/repair (I'm talking about worldwide manufacturers only, not small business)? If so, then what are those amps or AVRs using for controlling the volume? Thanks!

Inside Yamaha we have the R5F3640ECNFAD MCU made by RENESAS which is part of the M16C/64C Group of MCUs. I suppose that finding this part is indeed difficult, especially that is EOL, but most difficult would be to have it soldered and later programmed. I suppose, indeed, that having this MCU defective might make the amplifier unusable or very difficult to figure out a way to transform it into a Power Amplifier by rewiring the power wires...probably to bypass the SMPS and power the transformer directly etc.

 

[TheBatsEar]

I have an option to part ex my S-501for a 2011 vintage A-S1000 for around £200, good move?

The A-S1000 is able to deliver more current, it can drive any speaker to reasonable volume with ease.
It's a real audiophile style device, if you never had one, this will be a game changer. You will need a stout back because of the heft and a proper rack with a bit of depth too.
After fondling and hauling the A-S1000, the A-S501 will feel like an empty can with flimsy knobs, questionable terminals and an impossibly thin, folded aluminium foil style enclosure.

I would do it in a heartbeat, particularly if you consider that you can rebuy a A-S501 used for 250€/£200 anytime.

I would never dare buy an amplifier with uPC inside.

Are you serious? Are you one of those Luddite types?

 

[bdvan]

Don't overthink the amp question. I would buy a used A-S301/501 or R-S700, just to not waste money.
Then, after some time, i would recommend you buy a subwoofer (SVS SB-1000 is fine, used 400€ maybe). Regardless of your room or circumstance, it will allow you to listen to your music in full bandwidth. The Yamahas have sub-out connections.

I have a pair of KEF LS 50 monitors (old model without meta or wireless). I want to set them up in the living area to primarily stream Spotify and Apple Music the area itself is 20' x 15' and we should be able listen when we are in the kitchen at max 20ft from the speakers. I am pairing the speakers with a RSL Speedwoofer MK II. Looking for something in $1K range. I would get the A-S301/501 with a Wiim streamer if the amplifiers are sufficient enough to play without distortion at slightly higher than moderate volume level. I also saw a post you recommend Fosi v3 Class D amp, if Fosi works 60%-70% of a dedicated amp I can live without the rest of performance. Appreciate if you have any feedback.

 

[trl]

Fosi seems to have a lower output power than A-S501 and I haven't seen any measurements of this amplifier on real speakers (or a dummy load that properly emulates speaker's crossover), so I doubt that its stability will match the ones from A-S501. However, when you make up you mind on the final amplifier model please let us know.

 

[bdvan]

Fosi seems to have a lower output power than A-S501 and I haven't seen any measurements of this amplifier on real speakers (or a dummy load that properly emulates speaker's crossover), so I doubt that its stability will match the ones from A-S501. However, when you make up you mind on the final amplifier model please let us know.

I am leaning towards A-S701, however looks like Yamaha limits subwoofer cross over to 90Hz, while KEF LS 50 specs state a 79Hz crossover. Is there any workaround with this limitation?

 

[DMill]

I am leaning towards A-S701, however looks like Yamaha limits subwoofer cross over to 90Hz, while KEF LS 50 specs state a 79Hz crossover. Is there any workaround with this limitation

just set your sub crossover to 79 Hz. All that means is the Yamaha attenuates signal over 90Hz via sub out but would still be sending full range to your speakers. It would only be an issue if you wished to crossover at a frequency higher than 90Hz.