Ahh, you're looking at fancier stuff than me. As far as I know the HK amps (except for the digitals) are good 'ol class AB, which does dump some waste heat at idle (although not much, multiply it by 7 and all of a sudden you're getting warm).

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8