I never said the amp with the lowest MEASURED distortion is the best (Halcro or whatever). What I am saying is that the amp with the lowest SONIC distortion is the best. And of course, we could argue all day about what is distortion and what is real. The ear knows best. The measured distortion of an amp is only a measurement of about one one hundreth of its sonic distortion (yes, it is important but without the other 99+ things you can do you are just scratching the surface of true transparency). You could take the same design by the same engineer that measures incredibly low distortion on some meter and give that circuit to 100 different people to implement it as an amp.........Since there are so many variables that change the sound.....you would end up with 100 amps that all sound different from each other. I have taken Bruno’s basic amp design’s and made them better sounding by changing and eliminating certain parts. These changes cannot be measured. You just change the AC inlet on an amp to a better one and you have better sound. This game is infinite!
There is no such thing as "distortion below audibility". What we hear is WAY way more than what we can measure. You can just damp the heatsink of an amp and you will hear lower the sonic distortion.....no measurement difference. You can remove the steel plate and bolt from a toroid power transformer and mount it off the chassis on some wood and you will hear a more open sound.....again, no difference in distortion measurements, but way lower sonic distortion. This game is not simple. If you think it is that simple then why would you post on a forum where most everyone listens to things to determine what they like, want, and what they think is lowest distortion? Why are you an audiophile if you believe that all you need is numbers? Just buy a 1977 Sansui Receiver and a pair of Advents and be done with it.