Should Class A Amps be left on??

In part because the temperature difference between on and off is so great, the sound does change as the components warm up. (Obviously, designers work to optimize the sound after warm up, not during.) Keep them on, and you won't have to wait for the amps to warm up for an hour and stabilize every time you listen.

I used to own a big Class A amp that I left on continously for three years. Doubled my electricity bill and warmed my placed in winter (nice) and in summer (unpleasant). Sound was great, though. Now I have a Pass X350 that can be switched to standby mode. So far I have not found much difference in sound whether I leave it on continously or switch to standby. Just not sure what the cycles of heating and cooling could do to the amp..

It's your call Ferrari!, I have class A monoblocks, and they genearate a lot of heat! But they sound good if you leave the power on all the time..

Personally, I have had Plinius SA-100 mk3 amps, and I would not leave them on in Class A idle. First they suck up electricity. Second, the hotter the temperature of an amp, the less lifespan it has. Temperature affects amplifiers like everything else, it decreases the lifespan of the amp.

KF

Both tube and solid state amps can reach a stable operating temperature in about 15 minutes. I see no reason to leave the amp on when no one is listening just to save the warmup time. The electricity alone is enough to justify this. Didn't your parents teach you to turn off the light when you leave a room? Same goes here (and probably multiplied by a small factor if your amps are like mine: BAT VK-60). Just a few years ago we were all worried about using up the earth's resources. Whatever happened to that?

If you want to speed up the warmup process, just put a space heater under the amp. Then you only need to wait five minutes.