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

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!

Grannyring, Frank has brought to market some very
interesting designs and appararently he has a good
following, you don't see too much of his gear for sale on
the used market very often. But I would have to disagree
with his statement that all parts sound the same as long as
they meet specs. When I owned an Audible Illusions preamp
and had some of the caps in the signal path upgraded to
Mundorf caps, the end result was nothing short of
spectacular, the improvement was dramatic.

As far as warmup times this does vary from one manufacturer
to the other depending on design. For example if you look at
the Odyssey Stratos, many people for the price love it but
the biggest complaint is that this amp takes forever to warm
up and sound its best. No wonder the power switch is located
on the rear of the amp.

Grannyring, that's why I sais I WAS dubious.
My ears know 10 minutes is all it takes on my AVA 450 .
FWIW, I never met anyone I agreed with on everything.