Questions re:  GaNfet technology vs other designs.

My statement is absolutely true. Yours is not. I said it is impossible for your OTL amplifier to sound neutral compared to a high damping factor amplifier with any speaker that does not have a flat impedance curve.

And the fact of the matter that given the right speaker which may or may not have a flat impedance curve the OTLs can sound perfectly neutral (and to be clear those speakers are the exception rather than the rule). Just FWIW, I have the advantage of you on this point- we make an amplifier that has an output impedance that's difficult to measure and we can compare it to our OTLs and do so on a daily basis. Clearly you didn't read the article at the link I posted. Maybe you should. Or not... Tempest in a teapot, that sort of thing 😁

Let us unpack this fully. You are claiming that harmonic distortion 105 db below the fundamental is audible. Let us take an example of a 90db/watt efficient speaker, with 200 w/channel, what most would consider pretty loud. That is 90db/watt at the speaker. Let’s say 8 feet distance in a typical room.

Ever hear a system that sounds loud? If you work to really get rid of those pesky higher orders, you'll find that even at high sound pressure levels on a meter that the system no longer sounds 'loud'.

Put another way the sign of a good system is that it does not sound loud at any volume- it will always have a relaxed character. What you are forgetting is the ear converts distortion to tonality and it also perceived higher orders as loudness. This is why SETs can sound so 'dynamic' and its the source of brightness in most transistor amps. Easy to demo, FWIW... and is also why the right measurements on paper have a directly line to our listening experience (and likely why most of the time they are either not made or not published; I think the industry really wouldn't like people knowing what equipment sounds like by looking at the measurements...)

Its funny how so many people think the ear stops using its perceptual rules beyond an arbitrary point on a bit of paper.

@atmasphere you are twisting my words to attempt to win an argument. Clearly I said your OTL amplifier cannot be neutral compared to a high damping factor amplifier. You have said nothing that disproves that.

For your other amplifier, are you saying it is difficult to measure because it is low? And you are claiming it sounds "the same" as your OTL amp? I don’t believe you if that is the case. I am sure I could find some high impedance speakers where it may, but for most dynamic speakers, that just will not be the case. The frequency response variations are unavoidably large. In casual listening, you may convince yourself they are similar, in critical listening, they will not be.

Ever hear a system that sounds loud? If you work to really get rid of those pesky higher orders, you’ll find that even at high sound pressure levels on a meter that the system no longer sounds ’loud’.

I see no point in this post. Though I am almost always in ear plugs, I have done enough with pro-audio to know loud. Does it sound loud. Of course it does, even if the distortion is low, but it 0.5% low, which with music is inaudible.

You said that a harmonic 0.0005% down is audible. That is a 5db tone with a 110db primary frequency peak at the listening position. I really should clarify more. That is a 5db tone, when in addition to the 110db primary tone (the limits of our system and most people’s systems), that any non electronic music already has a ton of natural distortion that will itself mask electronic distortion including higher harmonics as the natural higher harmonics will mask other induced harmonics. This is one of the reasons why it is so hard to detect additional distortion in real music as there is already so much natural distortion.

Saying that "loud" is possible does not negate the lack of viability of what you have claimed. Put another way, it does not matter if it is SET or any other technology. You are starting with a conclusion and trying to work back toward a reason without showing the conclusion is true let alone viable.

Its funny how so many people think the ear stops using its perceptual rules beyond an arbitrary point on a bit of paper.

It is funny how many people arbitrarily make claims that cannot be backed up with demonstrations, but worse, are outside the realm of possibility.  I didn't even call you on the fact you said well over 105db down, I gave you the benefit of 105db down. Well down to most would mean another 10 or 20db lower.

you are twisting my words to attempt to win an argument. Clearly I said your OTL amplifier cannot be neutral compared to a high damping factor amplifier. You have said nothing that disproves that.

I'm not twisting your words, simply pointing out that without direct experience you simply are not in a position to know the truth of the matter; i.e. you are wrong. Not a judgement or anything, just didn't get the 'facts' right is all (and still abundantly clear you didn't read the article at the link I provided).

The reason the two amps sound similar is the distortion spectra is very similar (although fir entirely different reasons). The reason the class D sounds a bit more transparent is the distortion is quite a bit lower. You have to listen closely for the difference; the easiest way to hear it is that the class D is a bit better at bringing out detail in the rear of the soundstage (distortion obscures detail so this is no surprise). I'm by no means the only one to say this; our customers that have had both amps in front of them say the same thing.

To be clear there are many speakers were this won't be the case! But I didn't stay in business nearly 50 years selling amps to people when I knew they wouldn't work. That leaves a lot of speakers out there on which our OTLs are quite neutral. I refer you to reviews, as there are quite a lot of them...

Does it sound loud. Of course it does, even if the distortion is low,

A lot depends on what is meant by 'low'. In the case of whatever you were thinking of, apparently not low enough. When its a system you of course can't ascribe the 'loudness' being caused by the amps or speakers, but its pretty safe to say that in a proaudio situation where sound pressure is favored over fidelity, its going to sound loud.

I can't help you with not getting the point of my comment about loudness; FWIW a lot of people reading this thread will get it.

 Technics SU-R1000 Integrated Amplifier is GaNFET as is the Gato DIA 400s integrated Amp.

Someone asked about integrated GaNFET's earlier in this thread I think.