[goryu]

Please be more explicit.  Why does someone NOT want a fluctuating load? (and I agree, if we can avoid it, we should).  But why should we avoid it?

Speaker loads fluctuate, that's unavoidable. We want an amplifier that outputs the same at all frequencies regardless of the changing load it sees from the speaker. Why do you think we would want that?

[Tyson]

Speaker loads fluctuate, that's unavoidable. We want an amplifier that outputs the same at all frequencies regardless of the changing load it sees from the speaker. Why do you think we would want that?

Why would we not want it?

[goryu]

I have.  Maybe you should read him.  Because he actually you know, listens to stuff.  And has other people listen to stuff.  And then correlates that data of people listening to stuff to the things being measured.  Which has been MY ENTIRE POINT THIS WHOLE TIME. 

I'm not angry, just putting the main point in caps because you seem to have missed it pretty much continuously this entire thread.

No, I haven't missed it. It's an inexact science and while it has created certain generalities or rules of thumb, it's not an absolute predictor of individual preferences.

[goryu]

Why would we not want it?

As I have stated, hi-fidelity to the signal is generally accepted to be the goal of reproducing audio by many. A signal that is being modulated by the load impedance is not accurate to the source signal. On a more practical level, an amplifier that doesn't output independently of load is at the mercy of the load and will operate differently with different speakers, thus limiting the size of the market for said amplifier.

If I am going to design a telescope to look at the night sky I am going to choose the optics that give me the clearest, cleanest, most undistorted image possible. I'm not going to choose optics that punch up the reds, downplay the near ultraviolet, and otherwise give me a "pretty" image that is, while more pleasing to my eye, distorted.

[Tyson]

No, I haven't missed it. It's an inexact science and while it has created certain generalities or rules of thumb, it's not an absolute predictor of individual preferences.

No, that wasn't my point at all.  My point is that in audio, a combination of objective and subjective is needed to actually produce something that sounds good (or better).  Changing an amp (and thus changing a measurement) cannot, by itself, tell you if that amp sounds better, or not.  Only by adding in the qualia element can you even begin to try to correlate what you are measuring to how it will be perceived by a human. 

[Freo-1]

No, that wasn't my point at all.  My point is that in audio, a combination of objective and subjective is needed to actually produce something that sounds good (or better).  Changing an amp (and thus changing a measurement) cannot, by itself, tell you if that amp sounds better, or not.  Only by adding in the qualia element can you even begin to try to correlate what you are measuring to how it will be perceived by a human.

Rob Watts of Chord audio talked about this at length when giving his DAC Master Design Class.  He did extensive measurements,  then listened.  Based on what he heard,  went back and forth tweaking the design,  making measurements,  and then listening again.  He repeated this process until he was satisfied.


The video is available on YouTube. It's long,  but packed with good information.

[goryu]

sounds good or better to whom?

I can certainly disqualify an amp based on any number of factors without ever hearing it. This is in fact how most people make purchasing decisions. I wouldn't say whether an amp sounds "good" even after hearing it- I can only say if I like it or don't like it. There is no universal definition of "sounds good" so it's an ambiguous phrase with little practical utility.

[goryu]

Rob Watts of Chord audio talked about this at length when giving his DAC Master Design Class.  He did extensive measurements,  then listened.  Based on what he heard,  went back and forth tweaking the design,  making measurements,  and then listening again.  He repeated this process until he was satisfied.

He may be satisfied that doesn't mean there won't be others who aren't satisfied. This is how "house sound" is created.

[Freo-1]

Same can be said about amps. 

[goryu]

Same can be said about amps.

of course.

[Tyson]

Are you saying that this is how Bruno actually designs an amp?  Without ever listening to it?  If so, that would explain a lot...

[goryu]

Are you saying that this is how Bruno actually designs an amp?  Without ever listening to it?  If so, that would explain a lot...

That's one of the more ignorant things I've seen here. It wouldn't take much effort to find the answer to your question. Indeed, there is no accounting for taste.

[goryu]

From a review of the LSA GaN $3000 amp. It is said to use the same amp modules as the subject of this thread, the Peachtree GaN amp. Here is more proof of my point that GaN amps currently aren't really exploiting the claimed benefits of GaN tech, as well as showing how these amps aren't (yet anyway) proof of any step forward. Notice the load dependency.

[Freo-1]

This thread is about the Gan400,  not the LSA 350.   The Gan400 has somewhat different power specs, so assuming all the boards are identical without actually measuring one is not very scientific.  This is one of the reasons I've asked Peachtree to weigh in.   Many manufacturers often use the same base driver board, then make modifications to the original to enhance performance. 


It would also make sense to actually listen to the Gan400 as part of any evaluation, as it would for any piece of audio gear.  Check out the reviews tab from the link below.  The YouTube link from Thomas and Stereo is interesting.   At least one audiophile who owns Pass Labs  monoblocks loved the Gan400.   


https://www.peachtreeaudio.com/products/gan400

[goryu]

This thread is about the Gan400,  not the LSA 350.   The Gan400 has somewhat different power specs, so assuming all the boards are identical without actually measuring one is not very scientific.  This is one of the reasons I've asked Peachtree to weigh in.   Many manufacturers often use the same base driver board, then make modifications to the original to enhance performance. 


It would also make sense to actually listen to the Gan400 as part of any evaluation, as it would for any piece of audio gear.  Check out the reviews tab from the link below.  The YouTube link from Thomas and Stereo is interesting.   At least one audiophile who owns Pass Labs  monoblocks loved the Gan400.   


https://www.peachtreeaudio.com/products/gan400

As as been mentioned repeatedly, they are said to use the same amplifier board. Look at the photos on the links I have provided to judge for yourself. The power specs have everything to do with the power supply used, which isn't pertinent to this discussion.

There is no need to listen to the amp when evaluating it from an objective, design and performance, standpoint. Personal preferences are not transferable.

[Freo-1]

As as been mentioned repeatedly, they are said to use the same amplifier board. Look at the photos on the links I have provided to judge for yourself. The power specs have everything to do with the power supply used, which isn't pertinent to this discussion.

There is no need to listen to the amp when evaluating it from an objective, design and performance, standpoint. Personal preferences are not transferable.

You still don't know for a fact that the driver boards are identical.    As an example,  Jeff Rowland has in the past employed the ICE module, and made modifications to the board that a casual glance from a photo would not be easily seen.  It is entirely possible that Peachtree has had the base driver board modified.  We simply cannot say with certainty.  The measurements from Peachtree don't show the same variations. 


Measurements are important,  but honestly,  virtually all of today's gear measures fairly well.  They can give you some idea of what to expect sonically,  but they are not absolute.   Put 12 audiophiles in a room to evaluate a given model,  and you will wind up with 13 different opinions 😉


It makes zero sense (to me) to blow off listening to a given unit because one or more measurements doesn't meet one's perceptions. 

[Tyson]

It's not about meeting perceptions, it's about meeting state of the art objective performance measures. In case I haven't been clear the first 6 times, I am not interested in discussing perceptions, which can't be quantified or debated, but actual design and performance.

What's the point in maximizing performance in any particular area if it doesn't translate in to better perceived performance.  In other words, a frequency sag of 5db above 10kh is certainly worth correcting.  But going from .5db to .1db is that worth it?  I mean, sure it measures better.  But that probably has less affect on the perceived sound quality than focusing on optimizing some other area. 

No one here is say measurements don't matter.  But measurements alone can't tell you how your amplifier sounds.  Only actually listening to it can do that. 

[goryu]

That said, Goryu is the one who brought this fight to an otherwise innocuous thread talking about new amplifiers on the market, and is continuing to hammer on and on against the OP and others with common interests. 

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.

[Tyson]

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.

[goryu]

What's the point in maximizing performance in any particular area if it doesn't translate in to better perceived performance.  In other words, a frequency sag of 5db above 10kh is certainly worth correcting.  But going from .5db to .1db is that worth it?  I mean, sure it measures better.  But that probably has less affect on the perceived sound quality than focusing on optimizing some other area. 

"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.