Jason is using them on his Popori speakers. That's a good speaker.
Very easy to drive too. We were using one of the more entry level versions at AXPONA this year and it was rated 92dB which is pretty impressive for a panel speaker. Panel speakers are measured the same way all other speakers are: 2.83Volts at one meter. But with the microphone that close, a lot of the output of the speaker is not picked up. So functionally in the room to know what that 92dB figure means you have to add 6dB because if you are further back, the full output of the speaker can be experienced.
That's 98dB! We did not need the 200 Watts our amps were able to put out into that load. We could have easily used a 50 Watt amp and still had power left over. Their bigger speakers are rated as high as 96 dB, putting them functionally at 102dB!
That is indeed a belief, sans evidence and logic. How did the mystery unmeasurable "sound signature" get discovered, designed, engineered and manufactured into the widget?
The way that belief came around is because incomplete measurements have been used for over 60 years but presented as if there was nothing else to know. THD is a great example; if its high enough its also audible but we've been told for decades that it is not. Its not a useful measurement without knowing the circuit's distortion spectrum.
In that regard audiophiles have been lied to for so long they don't even think about it. They have to take the equipment home and play it on their own system to know, no matter what someone told them or what they read somewhere...
[
The Party (the measurement camp) told you to reject the evidence of your eyes and ears. It was their final, most essential command.] other than the bit in parenthesis, George Orwell, 1984.
We all know that ears use harmonics to tell the difference between sounds- that is how we know the difference between a trumpet and a clarinet. We also know that the ear is considerably more sensitive to higher ordered harmonics as it uses them to sense sound pressure (give a +120dB range, 'keenly' sensitive seems a better descriptor).
All humans use the same hearing perceptual rules; this is what made VU meters practical.
So when you add harmonics to a given signal, you alter how it sounds. The question is how much! SETs have that ever loving 'warmth' for which they are so well known. That's caused by the audible yet innocuous 2nd harmonic. This has been well known for well over 80 years and isn't rocket science (instead is music science). A Purifi module OTOH really should have no perceptible signature at all. IMO the reason people say they hear something in them they don't like is poor input buffer design and execution and poor power supplies. Also IMO if that is true its a really telling statement about how many bad designs are out there- how can you screw up an input buffer that badly? - but here we are.
Once you understand that the different sound signatures of different amplifiers is a combination of bandwidth, output impedance and mostly the distortion signature of the amp then you have the answer to your widget question. If the amplifier has an unpleasant distortion signature it will be an unpleasant amp to listen to even if its THD is low, due to the ear's sensitivity to higher ordered harmonics, which are assigned the value of 'harsh and bright'.
