Today I picked up my Atma-Sphere Class D Amps. These aren’t broken in yet. And they are simply amazing. I’ve listen to a lot of High End Class D. Some that cost many times what Atma-Sphere Class D costs. I wasn’t a fan of any of them. But these amps are amazing. I really expected to hate them. So my expectations were low. The Details are of what I’ve never heard from any other amps. They are extremely neutral. To say the realism is is extremely good is a gross understatement. They are so transparent it’s scary. These amps just grab you and suck you into the music. After I live with them some and get them broken in. And do some comparisons to some other high end Amps Solid State, Tubes and Class D’s, also in other systems I’ll do a more comprehensive review. But for now, these are simply amazing amps.. Congrats to Ralph and his team. You guys nailed on these.
How can you begin to know what someone will prefer? How can you begin to assume that you know what "better" means to someone else?
I answered that question several times on this thread. You deny its reality and I can't help that. So let's put it a different way- It really helps to keep up on research FWIW...
And yet it’s your product and you are the one making claims about your product and not providing measurements, saying "You either accept it or you don’t- much like you might if you saw a graph on our website- which you might believe or you might not." That sounds to me like "trust me". Asking and expecting me to trust some stranger is even worse.
And it isn’t, as I have said, that I don’t trust their hearing, it’s that I don’t trust their perceptions/taste.
What is a claim I've made? Just so we're clear on this. FWIW I've not asked anyone to 'trust me'. I was pointing out with that comment that such is an issue- its one thing for a manufacturer to put up information on a website. It's quite another when someone else does it. As a result I don't see the point; we already know what the amp does. The question now is really to our customers- do they think that the amps do what we said they would? My experience of the last half century is that if they don't think so they won't be customers.
And yet it’s your product and you are the one making claims about your product and not providing measurements, saying "You either accept it or you don’t- much like you might if you saw a graph on our website- which you might believe or you might not." That sounds to me like "trust me". Asking and expecting me to trust some stranger is even worse.
And it isn’t, as I have said, that I don’t trust their hearing, it’s that I don’t trust their perceptions/taste.
Its not by job to educate although apparently I do that with all the time I spend writing... Your position seems to arise out of you don't accept that the sense's perception and taste are two entirely different things! The former is autonomic and the latter conscious. So far as your writing is concerned, you conflate the two, which is a common mistake.
Not a lot of amps with distortion 120db down that would be said to have a "design issue".
Exactly!- but I said 100dB down IIRC and I do consider that an issue. Most of the numbers guys I run into think maybe -85dB to -90dB is acceptable. I know better, but good luck trying to convince them of that! So I don't bother.
Your reply sidesteps my statement, that is, that we can not accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d?
Actually it addressed it directly. In due time 'he' will prefer a class D amp as it will sound better, making the tube amp not worthwhile for all its extra hassle. That is what I said earlier. BTW this phenomena is already occurring.
You have painted broad strokes and made claims but not delivered on the proof. You are a manufacturer in a hobbyist forum with a self-interest in a product. I believe it reasonable to hold you to a higher standard. When someone is charging 4 times what a market leading product costs, never mind that it has half the output power, I think it unreasonable to just say "trust me".
This statement is false. Its not me you need to trust. Your trust issue is that you aren't aware that others can hear the same things you do- you don't trust their hearing since you think it can't be the same as yours. In the past you've suggested not in so many words that perception and taste are the same thing. At some point you will be disabused when you drop that story.
First of all, many of these amps, with different opamps, have been tested and while all the results I have seen show that the performance of the amp with these various third party buffer/op amps isn't quite at the level of the stock Purifi buffer and opamp, the measurements do not show any differences which would normally be considered audible in any way. In other words, if there were some issues with the design, one would expect significant differences.
IMO this is a classic example of how the industry in general does not recognize some fundamental properties of the ear brain system. Its as if research of the last 40 years is being ignored. The ear is a lot more sensitive than you think it is and so these differences are more significant than you think. Here's what that's about: the ear uses higher ordered harmonics to sense sound pressure. The ear has about a 130dB range which is pretty crazy. This means that distortion product 100dB down is audible if its unmasked. The ear assigns tonality to all forms of distortion (for example, higher orders are assigned 'harsh and bright'). BTW this latter fact of human hearing has been know for well over 90 years and should not be controversial to anyone but the uneducated.
So what might be considered 'insignificant' if often quite audible. Audiophiles have been dealing with this problem for well over 70 years now; its why we have to take stuff home to hear it for ourselves. This is the inconvenient truth of audio.
I use measurements to screen out products that don't meet my engineering, design/construction, and objective performance standards. From there, those which make the cut get further consideration and audition. I thus use both objective and subjective criteria. I see no contradiction in using both criteria in the purchase decision.
Well you're not alone in that. Everyone I know of does the exact same thing. The contradiction is in the way you've stated your position in the past. Thus I've revised my assessment; you're mistrust isn't others hearing so much as what meets their 'engineering, design/construction, and objective performance standards'.
We still have no way to accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d? Again, the fact that there are successful class d amps and tube amps is proof that there is no consensus subjective choice.
You wrote:
"In time, the tube amps will be gone. Not because of a lack of tubes but because they’ve been eclipsed and people will wonder why they go through the hassle when subjectively better sound is available at less cost. That hasn’t happened yet simply because class D has taken some terrible missteps in the last 20 years."
Your reply sidesteps my statement, that is, that we can not accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d?
Tube amps disappearing because they are a hassle and there will be subjectively superior choices seems a stretch-been hearing that for years. They said that about vinyl. And yet, both are still here and have their rabid supporters. Perhaps they will quit making tubes completely at some point but as long as there are baby boomers and nostalgia, they will survive. And if they do disappear, it will probably encourage someone to make fake tube amps. Wait, someone already is!
You continue to talk about the similarity in how we hear. Yes, the physiology of our senses is similar. The important distinction is that while we all have similar physiology- the transducers that input external stimuli- there are differences in functionality between individuals due to age, slight differences in physiology, etc. This means that while we all "hear" the same, the input to the brain, as empirical studies have shown, is not the exact same- there is a variation. More importantly, while we might all "hear" the same, we don’t all interpret the stimuli in the same way. Research has shown that the interpretation of perceptions is a complex function of experience, mood, and an untold number of biases. Thus, while we all have similar physiology, and "hear" similarly, we don’t all interpret what we hear in the same subjective way. This is proven by the wide range of differing products, each with their own fans. It’s also the reason why there are salt and pepper shakers on tables at restaurants.
You talk about masking of high harmonics. Wouldn’t it be preferable to not have to use 2nd/3rd harmonics to mask higher harmonics? I would prefer an amp that had all the distortion below the threshold of hearing rather than using such a trick to mask them. I suppose that if one were trying to mimic the "sound" of certain tube amps, this could be considered a feature rather than a bug.
1. Distortion versus frequency: flat or rising?
2. Frequency response vs load: independent or dependent?
3. FFT vs frequency: level of even, odd, 2nd, 3rd, later harmonics?
4. Distortion + Noise versus power for different loads: increasing or decreasing? Level?
5. Power stage efficiency vs power at different loads: comparison between GaN and regular mosfets
With people making claims of this amp’s superiority, I see no issue with asking for some proof. When the manufacturer states that there is a lot about an amp’s subjective performance that can be gleaned from the measurements, I say please show us.
You wrote:
"I have stated that some of the above are important parameters to look at. I’ve also stated that our amp has some of those properties. That the distortion does not rise with frequency isn’t something that needs to be shown; its a simple statement of fact (you could have surmised the truth of this by looking at my comments about feedback, Gain Bandwidth Product and of course distortion vs frequency). You either accept it or you don’t- much like you might if you saw a graph on our website- which you might believe or you might not. The bottom line here is trust. You don’t trust other’s opinions since you don’t trust their ears to work the same as yours despite the fact that all ears work the same despite your remonstrations. It is apparent though that you are embrace the subjective experience as anyone else here."
I disagree. You have painted broad strokes and made claims but not delivered on the proof. You are a manufacturer in a hobbyist forum with a self-interest in a product. I believe it reasonable to hold you to a higher standard. When someone is charging 4 times what a market leading product costs, never mind that it has half the output power, I think it unreasonable to just say "trust me". With other manufacturers offering complete measurements I find the "trust" argument woefully insufficient. That is certainly your right but I think it poor form in this venue.
You have mischaracterized my statements regarding my trust of the opinions of others: it has nothing to do with how our ears work and everything to do with differences in perception/taste, never mind the obvious issues of basing anyone’s judgment of an amp in their system and room rather than in my own. Nearly every amp on the market has those who like it, and those who don’t. Why would any rationale person base a $5000 purchase decision on the opinion of someone on an audio forum? No, I don’t value the subjective opinions of others on equipment but I do value my own and would never expect others to place any value in my subjective opinions . In this very thread we have seen negative comments about certain products that have had wide success in the market with many who praise the product.
You wrote:
"Second, you would do yourself well to drop one of two stories about yourself, either that measurements are the only thing to look at, or that you have to try it for yourself. You can’t take both positions at once since others see a contradiction even though you may not see it."
Again, a mischaracterization of my position. Your mistake is claiming I am taking the positions as you have defined them: I have never ever said measurements are the only thing to look at. I have said over and over that measurements offer insight into the engineering, design, and objective performance of an amp, and as such they have value. I use measurements to screen out products that don’t meet my engineering, design/construction, and objective performance standards. From there, those which make the cut get further consideration and audition. I thus use both objective and subjective criteria. I see no contradiction in using both criteria in the purchase decision. In fact, I know many rational people who do the same, whether it is audio equipment, automobiles, computers, etc.
You are not alone in misrepresenting my view. In fact, it seems so commonplace here that I almost have to believe it is being done on purpose in some twisted way to provide a point of attack and the "go back to ASR" smears.
Lastly, I would like to address your comments about Purifi amps and the use of various input buffers to "tailor sound" by several manufacturers. You made a statement to the effect that "if you can hear the opamps, there must be an issue with the design".
First of all, many of these amps, with different opamps, have been tested and while all the results I have seen show that the performance of the amp with these various third party buffer/op amps isn’t quite at the level of the stock Purifi buffer and opamp, the measurements do not show any differences which would normally be considered audible in any way. In other words, if there were some issues with the design, one would expect significant differences.
Reading through the various opinions on these amps, some prefer the Weiss opamp, some the Burson, others Neurochrome, and others have said that the stock Purifi buffer is their choice. Some describe one op amp one way, another describes the same op amp another. Measurements show no differences which can be considered to be audible. They may all be "hearing" the same way, but their brains clearly do not seem to be interpreting the input in the same way. We see this same thing with cables and all the wacky tweak products- none of them can be shown in most cases (poorly designed cables, for example, would be an exception) to do much of anything, yet some people swear they turned their system up to an 11, others say they hear nothing. Previous experiences, mood, biases, go a long way to explain this perception paradox, This is why I find no real value in subjective comments regarding equipment on forums such as this.
Finally, I wish you all the best with your product. You seem to be thoughtful, sincere, and committed to your craft.
We still have no way to accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d? Again, the fact that there are successful class d amps and tube amps is proof that there is no consensus subjective choice.
In time, the tube amps will be gone. Not because of a lack of tubes but because they've been eclipsed and people will wonder why they go through the hassle when subjectively better sound is available at less cost. That hasn't happened yet simply because class D has taken some terrible missteps in the last 20 years.
1. Distortion versus frequency: flat or rising?
2. Frequency response vs load: independent or dependent?
3. FFT vs frequency: level of even, odd, 2nd, 3rd, later harmonics?
4. Distortion + Noise versus power for different loads: increasing or decreasing? Level?
5. Power stage efficiency vs power at different loads: comparison between GaN and regular mosfets
With people making claims of this amp’s superiority, I see no issue with asking for some proof. When the manufacturer states that there is a lot about an amp’s subjective performance that can be gleaned from the measurements, I say please show us.
I have stated that some of the above are important parameters to look at. I've also stated that our amp has some of those properties. That the distortion does not rise with frequency isn't something that needs to be shown; its a simple statement of fact (you could have surmised the truth of this by looking at my comments about feedback, Gain Bandwidth Product and of course distortion vs frequency). You either accept it or you don't- much like you might if you saw a graph on our website- which you might believe or you might not. The bottom line here is trust. You don't trust other's opinions since you don't trust their ears to work the same as yours despite the fact that all ears work the same despite your remonstrations. It is apparent though that you are embrace the subjective experience as anyone else here.
If you'd like a tip to improve credibility here are two:
First, refrain from attacking others even when they attack you.
Second, you would do yourself well to drop one of two stories about yourself, either that measurements are the only thing to look at, or that you have to try it for yourself. You can't take both positions at once since others see a contradiction even though you may not see it.
I understand your point of view re: keeping this thread going for the appreciation and discussion of atmasphere's amps. I never intended to post to this thread as I won't own the amp but reading it from time to time caught my attention as to the cruelty displayed by kuribo in his relentless highjacking of the discussion and denigration of Ralph's amp as well as his character, in what he thinks is a veiled and clever manner.
That there are some here who've fallen for kuribo's tactics is not my concern. As anyone can see from his post above, he's of the impression that he's got the upper hand and is now playing the victim and using that for cover while attacking Ralph and his amp. Using memes like "doxxing" and feigning injury is part of his M.O. He's used it throughout this thread.
So yes, the mods will be made aware of this, shortly.
Personal attacks, insults, name calling, profanity: the last rhetorical refuge of those who have run out of ammo and are throwing the empty gun in desperation.
The moderators are indeed watching this thread. I expect there will be some action taken over the doxxing, profanity, personal attacks, name calling, and other despicable behavior here. Sad and pathetic.
A rather disappointing reflection on some of the regulars here who if they continue in their childishness the mods will likely delete this entire thread.
A rather disappointing reflection on some of the regulars here who if they continue in their childishness the mods will likely delete this entire thread.
see info below -- what is interesting about this troll is the user account dates back to 2000... so i am not sure it is a ’kid’ we are talking about - or perhaps the original user account was hacked... the writing seems alot like the infamous persistent troll that has used various usernames of late such as dannad, cindyment, deludedaudiophile, but perhaps it is someone different... 347 forum posts ’since 2000’ but over 300 of them in the last 90 days -- anyhow, i am sure the mods are monitoring...and hopefully they will take some action
I find the noise floor more distressing than the harmonic distortion. So the graphs could possibly add some insight.
There is a great deal of measurements that could add insight:
1. Distortion versus frequency: flat or rising?
2. Frequency response vs load: independent or dependent?
3. FFT vs frequency: level of even, odd, 2nd, 3rd, later harmonics?
4. Distortion + Noise versus power for different loads: increasing or decreasing? Level?
5. Power stage efficiency vs power at different loads: comparison between GaN and regular mosfets
With people making claims of this amp’s superiority, I see no issue with asking for some proof. When the manufacturer states that there is a lot about an amp’s subjective performance that can be gleaned from the measurements, I say please show us. I just find it hard to understand why the manufacturer makes the claim that measurements contain a great deal of information on the subjective performance yet won't publish said measurements. Especially at the price point. These are not unreasonable requests- plenty of other manufacturers publish this data. What’s the big deal? Why the angst and accusations of some nefarious ulterior motive?
This guy is just messing you guys. He appears to hold a grudge. A cursory look at his posts (which is all I can bear to do) shows he is talking in circles and sometimes contradicts himself. He's gotten better at covering his mistakes but in the end, he's just messing with you guys, trying to show how bright he is, which I think, is his main objective.
Assuming that once again you are belittling me with unfounded, unproven, baseless accusations, I can't help but wonder exactly what sort of grudge it is I hold and against who and what proof of any of this nonsense you care to share?
You know, in darkness, it doesn't take much of a light to appear bright...
Ralph-would you be willing to discuss your Class D amp in terms of being true balanced (or not)? Please explain the circuit topology in terms of inputting and amplifying the input signal fully true balanced throughout. And assuming it does not, isn't this a compromise?
Call it Class A-G if it makes you happy but at it's core, the Benchmark was based on a switching power supply which is why it weighs 12.5 lbs.
From S'Phile's coverage of RMAF 2013;
The Benchmark AHB2 amplifier, named in honor of the company's founder, Allen H. Burdick, who passed away just before the show, has a dynamic range claimed to approach 130dB, and outputs 100Wpc into 8 ohms, 170Wpc into 4 ohms and can be bridge to produce 340W into 8 ohms. THD+noise is said to be <–108dB relative to full output at 1kHz. John Siau explained that the THX modules are operated in a mode that gave the lowest noise and distortion rather than the maximum efficiency I wrote about in 2012. A key to the low THD is the use of 0.01%-tolerance resistors at critical points in the circuit. A switching power supply is used, Siau feeling that this was optimal because all the power-supply spuriae will be out-of-band and therefore more readily filtered.
This guy is just messing you guys. He appears to hold a grudge. A cursory look at his posts (which is all I can bear to do) shows he is talking in circles and sometimes contradicts himself. He's gotten better at covering his mistakes but in the end, he's just messing with you guys, trying to show how bright he is, which I think, is his main objective.
All the best,
Nonoise
Perhaps you’re right, but judging other people motivations is usually fraught with some danger.
And if we assume that he is genuine, then his request for metrics seems appropriate in the context of the amp.
You are aware no-one is going to beat Bruno's numbers any time soon. For that reason alone I really don't see what you are so concerned about what measurements we get. If that is the only concern just buy a Purifi and be done with it. The problem I see with that I already outlined.
…
I am sort of surprised to read ^this^…
I find the noise floor more distressing than the harmonic distortion. So the graphs could possibly add some insight.
I'm guessing that "kuribo" is the same person who repeatedly posted very similar comments on another online audio forum using the name "goryu." That discussion was focused on comparing the sonic differences between Ncore modules and Purifi modules. The poster in question stated over and over that personal opinions about sound quality are meaningless. Naturally, statements like that are consistently effective in pushing audiophile "buttons."
Pretty well defeats the purpose of showing all those measurements, even for someone like yourself!
I disagree- there is much more to be learned from a full suite of measurements than simply how something "might" sound.
While there are minor variations from individual to individual, these rules are shared by all people with hearing and they are far more alike than different
We still have no way to accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d? Again, the fact that there are successful class d amps and tube amps is proof that there is no consensus subjective choice.
If you believe measurements can indicate subjective sound qualities, publish your measurements and show us how. Show how the GaN fet is an advantage with numbers.
But that will never tell you with any real certainty if Random Joe will like your hot sauce. I don't buy based on market research- I try for myself. And I know many people that aren't going to pay $5000 for an amp because a group of people on an audio forum says its s'wonderful! They will want to hear it for themselves in their system, in their space. I also know many people who wouldn't even consider an amp at $5000 without seeing the measurements first.
Random Joe's taste in food is something quite different from his ability to taste- to detect flavor (and withstand a hotter sauce 😁). If you conflate the senses vs taste in the audio realm then the art of audio becomes impossible! Its not just Fletcher Munson- I chose that one because its so well-known that there is a switch for it (the 'loudness' switch) on many products. But there are other rules- here's one (easily proven by anyone with simple test equipment): the higher ordered harmonics are used by the ear to sense sound pressure. That one is ignored by the industry most of the time (which is IMO why there is so much stuff that is harsh and bright)... The masking principle is what made MP3s possible. While there are minor variations from individual to individual, these rules are shared by all people with hearing and they are far more alike than different! If you doubt that then all audiologists are just so many charlatans 🤣
The fact that you have to try it for yourself is understandable. As audiophiles quite literally because of limitations in measurement and how spec sheets are designed going back 70 years, despite whatever anyone has said about a product be it audiophile, reviewer, dealer or manufacturer, if his lips are moving he's lying. We've all experienced this so often in the audio world that we don't even think about it- we just have to get the product home to find out no matter what the spec sheet says.
We've had the ability for the spec sheets to really show what the equipment is going to sound like for some time. But it appears the industry would go into conniptions if they actually printed the evidence of why their gear sucks so much! (FWIW Bruno's efforts cannot be quantified since he doesn't sell a finished product. You only get to hear what someone has done with it and that isn't always good... so much for the amazing specs...)
So we still have to audition it at home and make up our own minds. Pretty well defeats the purpose of showing all those measurements, even for someone like yourself! By going with 'measurements only' you are open to confirmation bias. If you really want to be objective you have to drop the measurements thing. Sounds oxymoronic but this is the world we live in today...
What's important to the ear? The ear is just a transducer sending a signal to the brain. It's how the brain interprets the data that matters. Science tells us we don't all interpret our perceptions in identical ways- there is variation based on numerous factors. No model is perfect. After all, the Fletcher-Munson curves have been revised repeated over the years.
The ear is not a simple passive transducer. The brain actually sends signals. Back to the ear.
The AHB2 is a linear amplifier that surpasses the sonic purity of all class-A amplifiers. No amplifier delivers lower noise or lower distortion. The small, passively cooled chassis, cleanly delivers 480 Watts bridged mono into 6 Ohms, with additional reserves for driving difficult speaker loads. Unlike power-hungry class-A amplifiers, the AHB2 achieves a power efficiency that rivals that of a Class D (switching) power amplifier.
The feed-forward design even makes the more efficient Class H or G operation possible — with no rise in distortion at class H or G switch point (Class H, or G, rail switching at a 1/3 power threshold);
We all know that numbers often don’t tell the story of how something will sound
and yet the designer of the amp under discussion has said this:
Subjective opinions can carry quite a bit of factual information. If all those opinions say the same thing and the people producing them are unaware of each other they carry quite a bit of weight. It seems to me that you've still not made the connection of how important measurements are to the subjective experience (and I see that all the time on the subjectivist side as well...). The rules of human hearing are the reason why; as I pointed out earlier all humans use the same perceptual rules. So if we can sort out what's important to the ear, then we can make the measurements to show if we've made progress.
When I find out that there is a switching amp that thrills listeners whom I trust, I will be glad to audition one. History has shown that switching amps can ace measurement testing and bore the death out of the listener. No meat to the bones. No there there.
Any amp class can ace measurements and bore the death out of a listener. This is hardly unique to class d amps. Apparently the Benchmark mentioned above didn't excite every listener either, and it's not a class d amp, by the way.
In any case, it is not possible to properly assess any amp without also considering the speakers it will be driving. The best amp/speaker integrations will ALWAYS produce the best results. Nothing else is possible, though some amps will care less about what speakers are used than others.
And by extension, the space the equipment will be used in. With state of the art class d amps, the dominant barrier to accurate sound reproduction is the speaker and speaker/room interaction, no long the amp.
A lawyer might ask, in a court of law, ’which is it? Were you lying then or are you lying now?’ 😁 I’m not suggesting that you’re lying; I am suggesting that its impossible to be truly objective.
Subjective opinions can carry quite a bit of factual information. If all those opinions say the same thing and the people producing them are unaware of each other they carry quite a bit of weight. It seems to me that you’ve still not made the connection of how important measurements are to the subjective experience (and I see that all the time on the subjectivist side as well...). The rules of human hearing are the reason why; as I pointed out earlier all humans use the same perceptual rules. So if we can sort out what’s important to the ear, then we can make the measurements to show if we’ve made progress. The former is the tricky bit!
If you believe that there is factual subjective information contained in the measurements, then wouldn't that be reason enough to publish them?
I don't believe that the subjective opinions of others carry factual information for 3rd parties- that is the nature of subjective opinion by definition- they are feelings or thoughts based on perceptions. Opinion are not facts.
You can amalgamate opinions of a group and develop a model of group tendencies and use it to predict consumer behavior, the basis of market research. But that will never tell you with any real certainty if Random Joe will like your hot sauce. I don’t buy based on market research- I try for myself. And I know many people that aren’t going to pay $5000 for an amp because a group of people on an audio forum says its s’wonderful! They will want to hear it for themselves in their system, in their space. I also know many people who wouldn’t even consider an amp at $5000 without seeing the measurements first.
Yes, you have previously mentioned Fletcher-Munson curves and other such models of aural perception. I have made the point that all of these models you bring up are empirically derived from testing. As a result, their predictive power is only as good as their assumptions and test subjects. I have made mention of the fact that the Fletcher-Munson tests were based on subjects described as young subjects without hearing deficiencies- not really representative of this forum’s members. Also, as empirically based models, they are predictive of group tendencies as they are constructed around average responses from a sample. In other words, they have weak predictive power for any random individual. Again, as I mentioned earlier- for a manufacturer trying to reach a large target market, these models are useful. On the other hand, for an individual user, they are not going to tell you anything with any real certainty. I have made this point on numerous occasions but have yet to see you address it.
All opinions don’t say the same thing- how do they carry "weight"? What "weight"? In whose opinion? Opinions about products are all over the map- that is proven here every day. It is also proven by a market full of successful amps of every sort of class, type, and performance level. There is no one clear winner- there are many successful products which cater to different market segments- tubes/class d, vinyl/digital, cables matter/cables don’t matter.
What’s important to the ear? The ear is just a transducer sending a signal to the brain. It’s how the brain interprets the data that matters. Science tells us we don’t all interpret our perceptions in identical ways- there is variation based on numerous factors. No model is perfect. After all, the Fletcher-Munson curves have been revised repeated over the years.
No, I beg to differ as to the value of other’s subjective opinions when it comes making individual choices and the value of your claims regarding the predictive power of perceptive models on an individual level. Look no further than the marketplace.
You are aware no-one is going to beat Bruno’s numbers any time soon. For that reason alone I really don’t see what you are so concerned about what measurements we get.
Why would your measurements need "to beat Bruno’s numbers" in order to be of value to a potential customer? You claim there is a strong link between the measurements and subjective performance- so why not show how exactly?
Yours is a GaN amp and I presume you chose GaN fets for a reason. I would think you could demonstrate through your product’s measured performance exactly what advantages your product has as a result. You keep talking about distortion spectra and subjective perception of sound. I, and I am sure others, would find these measurements of your amp informative. It’s a competitive market place with many options available to consumers looking for state of the art amplifiers. Clearly you aren’t trying to compete on price, nor does it seem you are attempting to compete on objective performance. I can only assume that you are competing on subjective performance.
I would also point out that the transition from most tube amps to Class D amps is probably more challenging for owners than most. Most speakers that sound good to someone with a tube amp will sound different with most Class D amps.
Most loudspeakers are meant to be driven by a voltage source which is an amplifier that either doubles power as the load impedance is halved or cuts power in half as the impedance is doubled (tubes, if acting as a voltage source, do the latter and this does depend a bit on which tap is used on the output transformer).
A small number of speakers, but significant in high end audio, are meant to be driven by amps that behave more as a power source rather than voltage source (SETs are an example). The most likely embodiment of this is a tube amp that runs little or no feedback. Some of these speakers have level adjustments (meant to allow the speaker to be adjustable to the voltage response of the amplifier) on the back, like my Classic Audio Loudspeakers. If these adjustments are present they will have to be set up correctly but the speaker will accommodate both types of amps. Another example of this is the Sound Lab electrostatic.
I would also point out that the transition from most tube amps to Class D amps is probably more challenging for owners than most. Most speakers that sound good to someone with a tube amp will sound different with most Class D amps. As they would with most SS amps that also tend to have much lower output impedance and are also capable of driving more speakers well. Given that, I still suspect most tube amp lovers will be more pleased moving to a good quality modern Class D amp than others. But still in many cases, a move from tube amp to SS amp is also likely to involve a speaker change unless the listener is able to make the adjustment. I suspect many cannot.
Perhaps the Atmasphere Class D amp, coming from a vendor known for their OTL tube amps, is a more natural path to Class D for tube amp owners? One that is less likely to make owners jump ship on speakers they selected to sound good with their prior OTL amps? That would make sense. Just guessing though...have not done the homework yet on the Atmasphere Class D.
In any case, it is not possible to properly assess any amp without also considering the speakers it will be driving. The best amp/speaker integrations will ALWAYS produce the best results. Nothing else is possible, though some amps will care less about what speakers are used than others.
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