Review and Measurements of PS Audio S300 PWR Amp

[HammerSandwich]

Why would anyone choose the PS Audio??

Because they live in USA & value local support?

 

[ObjectiveSubjectivist]

Because they live in USA & value local support?

Exactly, there is a lot more going on when buying audio as any other expensive stuff/hobby.
Not everyone look for good price/performance ratio. Sometimes that's secondary matter.
Sometimes you are willing to pay more for company that you like. You just support them. (you like their philosophy, good marketing, nice looking cases... whatever)
and I'm not talking only about ps audio, just overall.

 

[Matias]

Fair enough.

 

[Davelemi]

This is an important review due to the many products using these modules. The Emotiva PA-1 monoblocks use the same modules (I believe) but without the additional gain stage. I would imagine they measure the same or better. $630 per pair including freight in the USA, sales tax may be added depending on where you live.

Why on earth does anyone think negative feedback is bad?

I’ve been happy with my pair so far. I’d send them in but my wife would have no idea why she can’t hear the TV.

 

[HammerSandwich]

Just mime speaking as Basil Fawlty did to the lady with the hearing aid. What could go wrong?

 

[Tks]

Conclusion: PS Audio does need ICEpower to build something decent.

Sure, this is still $1,5K for simple 300AS1s in a fancy case. But you won't have this level of build from either Nord, Rouge Audio, or Apollon.

I'm not seeing "this level of build" being all that spectacular to be perfectly honest. Seems alright, nothing offensive.

 

[peng]

Some designers said...

That these two trends exist among designers is a reality, with traditional amps.

To my knowledge it is not proven that much NFB is not counterproductive or the best. Links? Class A and AB.

Of course, here's one (please note that it is a two part article):
https://www.edn.com/design/consumer...fiers--Why-there-is-no-such-thing-as-too-much

I do take take it with a grain of salt, as people do tend to exaggerate when they want to make a point, and it is sort of common sense that "too much" of anything is probably not good. In this case, the author of the linked article is a well know and knowledgeable audio EE.

 

[DonH56]

Feedback is one of many trades in designing an amplifier (or any gain stage). To me "too much" feedback implies insufficient loop gain and bandwidth to support the closed-loop gain and load leading to instability, from DC bias issues to underdamped response (ringing), to outright oscillation. Another interpretation of "too much" feedback is when very high open-loop gain-bandwidth is required to achieve the desired circuit goals, e.g. a really poorly-performing design requires "excessive" feedback to meet spec. An example of the latter is a gain stage that is very nonlinear and thus requires high loop gain to provide low distortion, like a pure class B audio output stage. (Yes, I know they can be made to work and do save power.) It may be better to use higher quiescent bias current (shift to class AB) or tweak the design (use a different circuit with higher intrinsic linearity) instead of burning power and potentially increasing noise and decreasing stability in the pursuit of very high open-loop gain and bandwidth to attain the needed feedback.

Whilst rarely using absolutes, I can see where "no such thing as too much feedback" can apply with the assumption that all other circuit parameters are met. Or the circuit is refined to support the level of feedback desired.

FWIWFM - Don

 

[scott wurcer]

Of course, here's one (please note that it is a two part article):
https://www.edn.com/design/consumer...fiers--Why-there-is-no-such-thing-as-too-much

Reading the comments section on these articles is a form of torture.

 

[peng]

Feedback is one of many trades in designing an amplifier (or any gain stage). To me "too much" feedback implies insufficient loop gain and bandwidth to support the closed-loop gain and load leading to instability, from DC bias issues to underdamped response (ringing), to outright oscillation. Another interpretation of "too much" feedback is when very high open-loop gain-bandwidth is required to achieve the desired circuit goals, e.g. a really poorly-performing design requires "excessive" feedback to meet spec. An example of the latter is a gain stage that is very nonlinear and thus requires high loop gain to provide low distortion, like a pure class B audio output stage. (Yes, I know they can be made to work and do save power.) It may be better to use higher quiescent bias current (shift to class AB) or tweak the design (use a different circuit with higher intrinsic linearity) instead of burning power and potentially increasing noise and decreasing stability in the pursuit of very high open-loop gain and bandwidth to attain the needed feedback.

Whilst rarely using absolutes, I can see where "no such thing as too much feedback" can apply with the assumption that all other circuit parameters are met. Or the circuit is refined to support the level of feedback desired.

FWIWFM - Don

Yeah, that's understandable but that would not be considered good design. Such negative effects will more than likely be measurable on Amir's bench, probably audible to most people who are serious about sound quality too. Your last paragraph hits the nail in the head. Bruno Putzeys should take note, may be even edit his article with that in mind.

 

[peng]

Reading the comments section on these articles is a form of torture.

I wish they would pre-qualify them, but I guess that would go against freedom of speech..

 

[scott wurcer]

Bruno Putzeys should take note, may be even edit his article with that in mind.

I'm afraid it's too late for Paul M., he seems so far down his path I don't think anyone could change his mind. Charles Hansen of Ayre had the same extreme mindset on the "badness" of feedback. IIRC the Pono was in the 70dB SINAD range.

 

[maty]

I do take take it with a grain of salt, as people do tend to exaggerate when they want to make a point, and it is sort of common sense that "too much" of anything is probably not good...

https://linearaudio.net/sites/linearaudio.net/files/volume1bp.pdf

[ The controversy

Control theory is a vital and standard part of engineering studies: the effectiveness of negative feedback to keep jet-fighters airborne, ferries afloat and nuclear power plants a-non-exploding has somehow never become the subject of much controversy. Only in audio does the usefulness of feedback draw heated debate, with detractors saying that reasonably good measured performance obtained without feedback sounds better than excellent performance obtained with feedback. Pro-ponents opine that there is nothing wrong with taking a good amplifier and making it better by putting feedback around it, so long as it’s not overdone... ]

 

[peng]

https://linearaudio.net/sites/linearaudio.net/files/volume1bp.pdf

[ The controversy

Control theory is a vital and standard part of engineering studies: the effectiveness of negative feedback to keep jet-fighters airborne, ferries afloat and nuclear power plants a-non-exploding has somehow never become the subject of much controversy. Only in audio does the usefulness of feedback draw heated debate, with detractors saying that reasonably good measured performance obtained without feedback sounds better than excellent performance obtained with feedback. Pro-ponents opine that there is nothing wrong with taking a good amplifier and making it better by putting feedback around it, so long as it’s not overdone... ]

Control was my final year option, also happened to be my favorite subject so I may be biased, I love feedback, feed forward etc.

 

[AudioSceptic]

I'm afraid it's too late for Paul M., he seems so far down his path I don't think anyone could change his mind. Charles Hansen of Ayre had the same extreme mindset on the "badness" of feedback. IIRC the Pono was in the 70dB SINAD range.

Archimago didn't measure SINAD as such but it wasn't that bad <https://archimago.blogspot.com/2015/08/measurements-its-balanced-ponoplayer.html>.

 

[brodie_mc_choad]

Amir,

I've got a "monoblock" PS Audio m700 amp (basically the big brother of the stereo amp under test here with the Icepower 700AS1 module) and an Icepower 1200AS2 DIY kit (it's a very simple implementation - PS and amp are all on one board in a nice chassis) as well as an Oppo Sonica DAC3 DAC that I would like for you to test assuming you're interested in testing any of them. For that matter I also have a MyTEK Brooklyn DAC+ and a pretty rare semi-professional DIY Hypex NC502MP kit in a tiny chassis (that I think sounds the best of the bunch) - can't find any of those components/modules in your test archive.

What is the best way to reach you? In the mean time, how long do you normally need to hang onto these units before you get them tested and shipped back? In the case of the PS Audio I wouldn't care if you took it apart carefully for internal pics, but the chassis/case I used for the Icepower implementation is a little more of a hassle to take apart and put back together. The Hypex NC502MP amp is so tiny that it'd be a joke to even bother taking it apart even for photos or the edification of your readers. I do need to finish some solders in that one before I can send it anywhere though.

Shipping will be a pain in the ass - I'm in Texas, but I can send you one, then wait for test results, then do the other when I get the first one back, and so on. Feel free to email me at the address on file with my membership, again assuming any or all of them would be of interest. Look into the Hypex NC502MP if you get a chance - I am amazed by it, but I don't see it used in very many products. https://www.hypex.nl/product/nc502mp-oem/77

Let me know if you're interested.

 

[amirm]

Amir,

I've got a "monoblock" PS Audio m700 amp (basically the big brother of the stereo amp under test here with the Icepower 700AS1 module) and an Icepower 1200AS2 DIY kit (it's a very simple implementation - PS and amp are all on one board in a nice chassis) as well as an Oppo Sonica DAC3 DAC that I would like for you to test assuming you're interested in testing any of them. For that matter I also have a MyTEK Brooklyn DAC+ and a pretty rare semi-professional DIY Hypex NC502MP kit in a tiny chassis (that I think sounds the best of the bunch) - can't find any of those components/modules in your test archive.

What is the best way to reach you?

Just start a conversation with me and we can take it from there.

 

[brodie_mc_choad]

OK. Is there any one of those components you or the readers would like to prioritize? I have no preference.

 

[bunkbail]

OK. Is there any one of those components you or the readers would like to prioritize? I have no preference.

More PS Audio stuff is always better

 

[tktran303]

Paul McGowan is a salesman. Even his autobiography is full of hype

"Almost a bestseller..." OMG!!

As if it'd ever win a Purlitzer or Booker prize...
I guess even bad publicity is good publicity... just like his amps. If they're made by B&O they are faithful to the source. If they're made by PS Audio, it's a little bit of salt & pepper, some herbs here and there, just to flavour your sound...