"Fat: See Full and Warm. Or, *spatially diffuse* - a sound is
panned to one channel, delayed, and then the delayed sound is
panned to the other channel. Or, *slightly distorted* with analog
tape distortion or tube distortion."

Guitar players value tube gear in attaining a particular kind of tone in playing, not reproducing music. That doesn't really do it, either.

I don't think one needs to be an EE to hear the effects of feedback. It's necessary in non-triode amplicification, as most other devices are distinctly non-linear and need a little help. It's necessary when driving long cables. Outside of that, it's a music killer. The Audio Note M2 has switchable feedback. Choose what you like. Without it, the music flows free, full and lifelike. With it, the life is squeezed out of the signal, and the music falls very flat. but I digress; this is about push-pull vs single-ended amplification.

I guess, in the end, I don't see much point in debating this unless the participants can be in the same place listening to gear that embraces the opposing viewpoints, so I'll withdraw.