I have seen it too many times: "The amp sounded loud, even when only turned up to 2, but the other amp had to be cranked up to 6." Or something like that. The volume control is not a power knob. Volume and gain settings are not a way to compare power levels, because these controls are designed to react differently in different amplifiers. Like it or not, unless you believe the specs (itself the subject of endless threads), if you want to compare power levels, you can only do it by cranking each amp to the point where the power amp and not the preamp is distorting at a level that begins to sound bad. You have to hold the test conditions constant, e.g., by using identical speakers in the same kind of room setup. How you do this without going deaf, when amps are routinely being made with 600 Watts or more, is a total mystery to me. But fortunately I don't have a dog in that fight.