IH, no, the power consumption rating on an audio receiver or amplifier typically is an average consumption rating unless it's specifically termed "maximum", "full power", etc. This results in some screams of fraud when it's noticed that, for example, a 7x100 watt receiver has maybe a 500 watt power consumption shown on the back panel. Having heard that class AB amplifiers are maybe 50% efficient, they think that if the power output rating was true that the consumption would have to be around 1400 watts.
Well, the power rating is true(has to be so as to not be in violation of the FTC amplifier power regulations)but the consumption rating can also be accurate. An average usage number might be taken with 1 channel driven at full power and the other 6 at 1/8th power, which also happens to be the standard that Underwriters Laboratory uses when testing for overheating, since that's considered to be roughly the average usage that occurs in home audio. The channel driven at full power runs at about 50% efficiency in a class AB amplifier, but the efficiency drops off at lower power levels and might typically be around 25% at 1/8th power. So, the consumption would be about 200 watts for the channel driven at the full 100 watts with 50% efficiency plus 300 watts used for the other 6(1/8th x 100 x 6 = 75 watts total output, using about 300 watts at about 25% efficiency), and that's why the plate on the back shows 500 watts consumption.
