it depends on the design.
yes.....
classA have efficiencies of not more than 50%, meaning for every 50 watt of power output, 100 watts of input is required,
so the other 50 watt is wasted in the form of heat...
class AB at around 65% so that for an output of 65 watts, 100 watts of input is required, the other 35% wasted in form of heat...
class D otoh, has and efficiency of about 90%, so that for a 90 watt output, 100watt power input is required, only 10watts is wasted as heat....
now all the above is just the output stage, what about the power supply? it adds to to total power input....
and what about tubes?
i have seen a single ended tube amp draw 90 watts for a mere output of 3 watts per channel..
i have seen pp amps that has a power consumption of 210 watts for a power output of about 30 watts per channel....
but not to despair, listening to music wherein you are not using more that 10 watts even at high volume levels, things will not be so bad....
we have done full power FTC testing of a 1kw ss amp using sine waves and dummy loads, and when we tested the same amp using a speaker load, we found that a 200 watt level is already very painfull to the ears and hard on the chest...
if you want to find out your actual power consumption, you can get one of this:
in the picture is my diy power monitor, the amp being tested is a 6c33 OTL amp, as the reading indicates,
heaters alone draws 210 watts.....filaments pa lang yan....