<brayeagleerik wrote: ". . . Peter Walker’s conclusion was that all well-designed amps operated below clipping will sound the same."
A Peter Azcel posit? (The Audio Critic)>
You can also add Alan Shaw (Harbeth) to that already esteemed list.
However, Ken Rockwell back in 2015 posted a technically logical explanation why tube amps are often preferred.
https://kenrockwell.com/audio/why-tubes-sound-better.htm