Seems like the best "upgrade" for tube amps....

Interestingly, a few hours of warm up applies to solid state gear as well. In fact the manufacturer of my solid state preamp recommends at least two days of warm up before listening, then leave it on continuously, turn it off and you will start over! I believe that these warm up periods involve the electrons finding their shortest signal path as well as transistors or tubes reaching their optimum temperature.

Jolida 502p, and I run it a lot.

With solid state gear if you want it to really sound right it probably has to be left on all the time- especially preamps.

Our amps seem to get to 99% of where they are going in about an hour- two hours they are totally there. In the old days it took more like three. I credit component improvements for the shorter time these days.

I have a Van Alstine Synergy 450 which has 12 separate power supplies,
Frank made the statement there were at their best within 10 minutes.
I was dubious but he was correct.

Well Frank at Van Alstine also says all caps, wire, parts etc... sound the same as long as they meet spec. I was close to buying some gear from him until he went off on that subject. I quickly realized while he is a great designer, he does not understand some other things that impact sound quality. Like worm up!