I have just come across this sentence on another blog I write for and thought it will make a few people laugh as it did me. It is a classic . How to list the power output of an amplifier. "It’s fairly straightforward. The mains power (240V at up to 10A, or 2400W max hereabouts) is fed through a transformer with around 85% efficiency, giving us say 2100W max, then rectified and filtered, then fed through a class A-B power amp with maybe 60% efficiency, giving us say 1200W max from a mains plug. Finally they feed the power through a complex marketing bullish!t network, and put 4kW out to the speaker. Funny enough, the whole mess only weighs a couple of kilos, so it must be terribly clever". Thanks to RayLi for this gem.