Can you leave class D amps on and not ever turn them off?

Guidocorona, it couldn't hurt anything to try on occasions as long as you power everything down first. You could actually leave the system unplugged for a few minutes then plug back in. This is a tweak that won't cost you anything.

I think that leaving any component on permanently can cause it to lose its best performance. Even Paul Mcgowen said if you unplug all your components from the wall and then plug them right back in, it can actually improve the system's performance.

George can you give us a couple of examples of the ones that go up in smoke?

Grannyring, give it a try. Afterwards of course you will still have to wait for it to reach its optimum operating temperature for best sound but it will provide better overall sonics for a while. Let us know later if this made a difference.

I hope when their switching power supplies blow they won't destroy the speakers, but I suppose that is why they are protected by a fuse.