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.

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.

It is possible that Frank feels that there is no substitute
for good engineering, even expensive parts. Case in point I
purchased a cheap chinese preamp, called Modwright to have it
upgraded. He asked me what would you have me do to it if your
not happy with the sound in general, I did read between the
lines at that juncture and let it go. But there are good
products out there that do benefit from upgrades.