What you are descibling is class B or A-B.
A 50w class A will draw the same current (power) regardless of the input signal up to the clipping point, or with zero input signal the
power disapation is still 50w. This is one reason they are so "clean sounding". The power supply does the heavy lifting and there is not much surge energy taken from the mains supply itself, to top up the power supply capacitors.

Last edited by ChrisW66; 2024-08-27 12:55. Reason: improved explanation
561, HD621, DSP5000s(24/96), DSP33C, DSP33 surrounds, Pioneer DV575A CD/SACD/DVD-A, Panasonic DB170
(561 to be replaced with G68 shortly.)