I use a Fosi Audio and yea, it gets slightly warm. I measured the power consumption when there is no signal and it's right at 1 watt. When it's at high volume I get an average of 4 watts. I decided it's not worth turning it on and off with that kind of consumption. It replaced a power hungry class A amp that had a 2Kw power supply. Just turning that sucker on dimmed my lights as the caps charged. At idle, that amp drew a modest 100 watts. Sure, my old class A 100lb behemoth sounded slightly better in that it could belt out a lot of bass with little distortion. But it was big, got very hot and heavy. My class D amp is about the size of a pack of cigarettes, gets slightly warm so I stuff it inside a cabinet where you don't see it. I'm not going back to class A, A/B again.