[Tyson]

"Better" perceived performance by who? There is no one who can make that judgment for anyone other than themselves. The point in maximizing performance is to produce a larger version of the input as truly as possible. That's the purpose of an amplifier and the goal of an amp designer. There is no accounting for taste, as has been said over and over. You don't like Purifi. Fine, don't buy it. Just because you don't like it means nothing in the market where many others do. It says nothing about the quality of the amp, it's only your opinion. That's called a free market. No, measurements can't tell us whether we will like an amp, they only can tell us if it does it's job and how well. You put it in a room with associated equipment and you listen to a system. Maybe you like how it performs as a whole, or you don't. Your experience isn't anyone else's experience and means nothing outside of your head in your room with your system. If you want to call any amplifier "good" or "bad" and have it mean anything, you need to focus on quantifiable, provable, factual data, not subjective opinion. How well does it meet the goal of a wire with gain? That is a starting point. If it does a poor job, what's the point in listening? I don't want to hear distortion, no matter how much I might like how it sounds. I want the original signal, for better or worse. There are those who simply can't handle the truth and want flowers and chocolate. Again, no accounting for taste.

And I want an amp that actually sounds good.  I guess some people don't care about that.  Like you said, no accounting for taste.

[goryu]

goryu, your argument amounts to "amps with better measurements have better measurements".  That's tautological.  It also strands you in a closed system with no reference point outside of that tautology. 

Here's my point, yet again. If you optimize an amps measurement and people tell you it sounds worse, do you just dismiss and ignore that feedback as 'subjective' and thus not worth investigating?  If so that would make for a poor design process.

No, that's not my argument.

And what if other people tell you it sounds "better"? There is no truth in subjective judgments- the corollary is you can't please everyone. That's why there are amps of many types and colors in the marketplace- an amp for every seat, as it were...

[Tyson]

No, that's not my argument.

And what if other people tell you it sounds "better"? There is no truth in subjective judgments- the corollary is you can't please everyone. That's why there are amps of many types and colors in the marketplace- an amp for every seat, as it were...

So how do you verify that it sounds better if you make a change to it?  Again, measuring better does not actually mean it's closer to straight wire with gain.  It just means it measures differently and that may (or may not) correlate to actual transparency. 

[goryu]

And I want an amp that actually sounds good.  I guess some people don't care about that.  Like you said, no accounting for taste.

You again make claims for others. Who are you to decide for others what sounds good? Who are you to judge what other people care about? People can choose whatever criteria that want to make their purchase decision, it's a free market, a free country. Ultimately everyone settles on something that gives them pleasure and enjoyment. How they choose, what they choose, and why they choose is a personal decision.Some people just can't accept the utter meaninglessness of their own value judgments to others. Live with it.

[goryu]

So how do you verify that it sounds better if you make a change to it?  Again, measuring better does not actually mean it's closer to straight wire with gain.  It just means it measures differently and that may (or may not) correlate to actual transparency.

How do you verify if it sounds "better"? Again, "better" is subjective and can't be measured. It might be better for you and worse for someone else.

Lower distortion, lower noise floor, liner frequency response, etc., when measured "better", mean by definition that the amp is performing "better", i.e, closer to a wire with gain, if that is the goal. The closer the output is to the input, the closer the amp is to a straight wire with gain.

 "Transparency" is a subjective judgment and is meaningless when assessing the objective performance of the amp.

You keep mixing subjective and objective criteria. Logic doesn't allow it.

[Freo-1]

First of all, the OP made a claim about GaN use in class d amps: they that moved class d forward. Since there is no way to measure subjective performance, and no way to prove opinions, the only meaning this statement can possess is in the objective realm. I disagreed. Instead of arguing the design and performance on a objective basis fitting the claim, several people have chosen to make fallacious subjective claims, failing to support the original claim.

I reject the characterization that I don't believe there is merit to subjective listening, which is absurd on its face. Everyone listens, that's the point, isn't it? The difference is I don't believe my own subjective impressions are meaningful to anyone but myself and rather, take umbrage at those with the chutzpah to believe their own personal impressions are somehow factual and meaningful to others. There is no rational point in arguing subjective impressions- opinions are not facts and can not be debated. The fact that someone screams how great their product is means nothing in reality about the product. It's all so much noise. The only meaningful debate is on the facts, something I have produced on numerous occasions here.

It occurs to me that you are ignoring some facts yourself.  GanFETs have better behavior than MOSFETS.  There are measurements to prove that.  You have not acknowledged that Peachtree may have revised the driver boards,  we simply don't know.  I hope to hear back from them.  Cannot blindly assume the
Peachtree and LSA are identical in every way.  Specs say they are not. 


Feedback usage in amplifiers is still an ongoing debate among audio engineers.  While there is consensus on the advantages of feedback in general, there is not consensus about what feedback does to sound.  Using a ton of feedback to work around MOSFETS limitations is not needed to the same extent,  since GanFETs are in fact superior in a number of key parameters. 


There is also an argument to be made that while measurements do capture a lot, they don't capture every possible variable with a given design.  Speaker loads are not test bench measurements.   Engineers don't just measure and release gear. They listen,  make adjustments,  go back and listen again,  and repeat until they are happy.

[dflee]

I shouldn't do this but oh well.
goryu: you make a point in what you are stating BUT,
I for one respect and enjoy reading posts by Tyson and Freo1.
Their comments are fairly much in tune with my thoughts and while I'll never be able to afford the equipment they have
I find it fun to read what they are thinking. Has very little to do with specs and charts and how to read them and all that other bullship(t)
We are here as a community and thus are here for enjoyment. That in itself becomes personable. One does not become friends on threads if they come across as egotistical with facts and without personal experience with a piece of equipment yet posts as such. There is only so much time for listening to every piece of equipment out there and again while goryu wants his decision making only based on specs than that's his opinion and I respect that but don't tell everyone else to do the same and not discuss it. I thought that's what AC was all about.

Don

[Early B.]

Y'all have been going around in circles for the past 5 pages. Let's get back on track...

I, too, am quite interested in Freo, Tyson, and others' opinions on this amp and similar ones who have actually heard them, and would love to hear more. Opinions, including our own, are the basis upon which we buy 100% of our gear. So yeah, opinions matter, but not all of them.     

[Freo-1]

I shouldn't do this but oh well.
goryu: you make a point in what you are stating BUT,
I for one respect and enjoy reading posts by Tyson and Freo1.
Their comments are fairly much in tune with my thoughts and while I'll never be able to afford the equipment they have
I find it fun to read what they are thinking. Has very little to do with specs and charts and how to read them and all that other bullship(t)
We are here as a community and thus are here for enjoyment. That in itself becomes personable. One does not become friends on threads if they come across as egotistical with facts and without personal experience with a piece of equipment yet posts as such. There is only so much time for listening to every piece of equipment out there and again while goryu wants his decision making only based on specs than that's his opinion and I respect that but don't tell everyone else to do the same and not discuss it. I thought that's what AC was all about.

Don

Well stated, and thank you.  To me, this is not personal, it's about a legitimate difference of opinions about how audio gear actually sounds!   Measurements are used to help explain and correlate what one hears.  Having said that, measurements can't actually tell one everything about the sonic qualities of a given product.
IF a product measures bad, then it will not sound good.  However most everything made today measures reasonably well. 


Just heard back from Peachtree.  Here is the crux of their response:


"We are continuing to receive feedback about that review and are preparing a written piece to address the questions people have and to hopefully clarify a few things. In short, measurements like SINAD are one thing and listening is another thing. Both have their place in audio but in some designs, better measurements can actually sound worse. We've experienced this with DACs and amps. Many times a trade-off. In any event, we expect to be answering many of your questions more as GaN continues to become prevalent in our industry and others. Once our document is complete, we will send it to you and probably post it on our website for others to see. "   

This is essentially the argument myself and others have been making.    Please note the manufacture is indicating that Gan will continue to become prevalent, or move forward as it were.

[Stercom]

Some people trust their ears and some people don't.

[Phil A]

Some people trust their ears and some people don't.

For sure.  The process of getting these amps (Peachtree, LSA and Wyred4Sound) out to market was a process that took about a couple of years (of listening to various iterations of listening and measurements). The team involved in doing the evaluations included representatives of those companies (and with tons of real experience with a full range of audio products and what else is available in the marketplace).  They also took heat for the delays as there were announcements about coming to market sooner.  They waited until they were able to make a product right at a particular price point. 

[Tyson]

Just heard back from Peachtree.  Here is the crux of their response:

"We are continuing to receive feedback about that review and are preparing a written piece to address the questions people have and to hopefully clarify a few things. In short, measurements like SINAD are one thing and listening is another thing. Both have their place in audio but in some designs, better measurements can actually sound worse. We've experienced this with DACs and amps. Many times a trade-off. In any event, we expect to be answering many of your questions more as GaN continues to become prevalent in our industry and others. Once our document is complete, we will send it to you and probably post it on our website for others to see. "   

Game, set, match.

See, this is what REAL audio designers do - change something, measure, listen, repeat.  I'm not sure what goryu's daytime job is, but I sure hope it's not "design audio equipment".

[goryu]

It occurs to me that you are ignoring some facts yourself.  GanFETs have better behavior than MOSFETS.  There are measurements to prove that.  You have not acknowledged that Peachtree may have revised the driver boards,  we simply don't know.  I hope to hear back from them.  Cannot blindly assume the
Peachtree and LSA are identical in every way.  Specs say they are not. 


Feedback usage in amplifiers is still an ongoing debate among audio engineers.  While there is consensus on the advantages of feedback in general, there is not consensus about what feedback does to sound.  Using a ton of feedback to work around MOSFETS limitations is not needed to the same extent,  since GanFETs are in fact superior in a number of key parameters. 


There is also an argument to be made that while measurements do capture a lot, they don't capture every possible variable with a given design.  Speaker loads are not test bench measurements.   Engineers don't just measure and release gear. They listen,  make adjustments,  go back and listen again,  and repeat until they are happy.

I have never said there aren't advantages to GaN devices, all I have said is that no one to date and surmounted the engineering challenges to exploit them in class d. Witness the performance of all GaN amps to date- none mentioned here are using a switching frequency that takes advantage of their many pluses. There is no step forward in performance to date.

I think this says it quite well:

"I would say there’s almost a moral duty to try and keep personal tastes out of audio design. It is a matter of respect to artists not to “remaster” their work. Euphonic modifications are fair game on the production end when artists are in charge, but the reproduction end should not add further commentary to that. Commercially, too, it makes sense. Unless, for some strange reason, everyone has the same biases as oneself, a neutral sound will, on the whole, gain you most friends. And, of course, as I already intimated, neutrality meshes well with the engineering approach. If you design for absolutely flawless measured performance, the result turns out to be sonically neutral too." Putzeys

[goryu]

Some people trust their ears and some people don't.

Not quite: most people trust their own ears but some don't trust the ears of others.

[goryu]

Game, set, match.

See, this is what REAL audio designers do - change something, measure, listen, repeat.  I'm not sure what goryu's daytime job is, but I sure hope it's not "design audio equipment".

Really? What have they really said about the switching frequency, the output filter, the load dependence? Where are the specs? Nothing. Just more fluff. Your response shows bias and the willingness to believe what someone tells you as long as it agrees with your viewpoint. So much for critical thinking and objective analysis, not to mention wishful thinking.

[Tyson]

Really? What have they really said about the switching frequency, the output filter, the load dependence? Where are the specs? Nothing. Just more fluff. Your response shows bias and the willingness to believe what someone tells you as long as it agrees with your viewpoint. So much for critical thinking and objective analysis, not to mention wishful thinking.

And your replies have shown a willingness to completely discard other people's viewpoints when they don't agree with you.

[Early B.]

I think this says it quite well:

"I would say there’s almost a moral duty to try and keep personal tastes out of audio design. It is a matter of respect to artists not to “remaster” their work. Euphonic modifications are fair game on the production end when artists are in charge, but the reproduction end should not add further commentary to that. Commercially, too, it makes sense. Unless, for some strange reason, everyone has the same biases as oneself, a neutral sound will, on the whole, gain you most friends. And, of course, as I already intimated, neutrality meshes well with the engineering approach. If you design for absolutely flawless measured performance, the result turns out to be sonically neutral too." Putzeys

What does "neutrality" sound like? The term itself is super subjective.

[SteveFord]

I have very little interest in this particular amp as it's not my cup of tea.
As for specs and measurements, well, that only goes so far.
Some of the great specs amps make really good subwoofer amps.

If Tyson or Freo-1 say it sounds pretty good you can be sure it sounds pretty good and is worth a look if you're in the market.
You'd still want to give a listen for yourself, though, as everyone likes something a little different.
Otherwise, we'd all own the Mighty Bose Wave Radio.

[mresseguie]

Regarding Bose Wave Radio:

My son’s had one for something like 8 years now, and still likes it. This helps explain why he has no interest in hi-end audio. 

[goryu]

And your replies have shown a willingness to completely discard other people's viewpoints when they don't agree with you.

You have yet to address the issue. All you do is talk about the importance of listening to evaluate and your subjective biases. You haven't added anything to support the argument that these GaN amps are moving class d forward in any factual way. It doesn't matter how you think they sound, good or bad. Subjective opinions are not debatable. The issue isn't one based on subjectivity, it's a matter of objective performance- you can't seem to grasp the simple truth that objective questions of fact require objective proof to debate, not your, or anyone else's, subjective opinion. I'm not discarding your viewpoint because I disagree, or agree, it simply that opinion has no relevance in the debate.