@analog_aficionado ..."I’ve built, lived with and loved tube amplifiers with rather embarrassing distortion figures compared to the modern benchmark. I’ve also built solid state amps following the guidance of famous objectivist Douglas Self, and while the result measured extremely well (~0.004% THD), the subjective listening experience of my earliest efforts was... disappointing to put it mildly. I kept using my tube amps while spending years trying to decipher how to build a better sounding solid state amp."...
I’ve always been fascinated about this part of amplifier design and the few remaining OG designers who still choose to use their ears to decide what sounds right to them for the final version that goes to production.
As for the amplifiers that I’ve owned or borrowed and enjoyed the most, none really offered what anyone would refer to as spectacular measurements.