Electrolytic capacitors are employed in the power supply and often at other locations. Such caps have two "shelf life" specs, one is "dry" (caps not powered up) the other is "wet" (caps powered up). The latter is about 30% longer than the former. IOW, caps powered up last longer than caps not powered up. Just the nature of the beast. Generally, replacing these caps is the first service requirement of major cost.
Hi James.
First, I must say that it's not because I have a diploma in electronics
and that's have been working with capacitors for more than 25 years
that what I will say is word of God, but I’ve been selling
and repairing professional photographic flashes with built-in storage capacitors
varying from 100uF to 3600uf. Don't seem to be much,
but in each unit there are 4 to 8 of them.
What I've been told by the manufacturer is that a capacitor must be cycle every three months to re-form the inside; otherwise it will be distortionned, however;
I had capacitors in storage for 6 to 12 months and some times up to a year
and when they were installed, I did not have any problem.
Now, what I know about electronics, is, if you leave it on 24/24 if it’s well designed and well ventilated, the temperature will stabilized and there will be less stress on all the components.
Cold – hot – cold, does expand and contract the components,
which is not too good for the components?
Now tubes units have a much shorter life than transistor, therefore,
I don’t think it’s a good idea to leave it on 24/24 plus safety concern if it failed.
For my tubes units I think 15 minutes warm up is more than enough and solid state units I would say the same.
Each unit is different; therefore the owner should start using it right away to find out by himself if the sound gets better as the unit warm up.
The Montreal local TV station had a dozen ss amplifiers on 24/24 for almost 20 years with no problems whatsoever, I am not saying that the performances where the same as when the units were new, but…
Just my humble opinion based on my experience with my products.
Guy 13