Amplifier warm up

Really? I'm the only one who thinks, seriously, that having dinner is going to change one's perceptions just as truly as an amplifier's warm-up?  (I know if I'm waiting to eat, I respond to music a lot less happily than after a nice dinner.)

Actually, i agree with both the OP and N80.
Yes! solid state warms up, and over a 30-60 minute period the majority occurs. Many solid (state) reasons.
That said, everything sounds better after a glass of wine, or with stable blood sugar or whatever. So joking or not, N80 is, IMO, absolutely right. Since i design commercially, i have to account for the many things that might fool me into thinking something is better or worse. And how i feel is culprit #1.  That's why subjective evaluations are so difficult, and generally viewed as without credibility. Yet i wont argue that we need listening - i cannot measure most differences that i can reliably hear.
G

My sugden class A takes a good 90 minutes to sound its best, not that it sounds like crap prior....it also makes for a great space heater in winter.

There’s a reason why most SS amps have the on/off switch hidden inconveniently on the back - they expect you to leave the gear running. As one commenter noted, though, yes, the components do deteriorate over time (I just replaced a Conrad Johnson amp that had run almost continuously for 12 years; over the last year I had noted that the bass response was degrading). Counterpoint is that the majority of electronics failures occur during power up. Pick your poison?

atmasphere = +1 (and; more = better)