On my Kenwood KAC-7201 amp I have a nob that has that label to it. I was under the impession that your are supposed to set it to what your pre-amp out puts are on the HU. But, this nob ranges from "5" to ".2". Under ".2" it says "MAX", and under "5" it says "MIN". Shouldn't it be the other way around? Because 5v is higher that .2v? When I turn it towards .2 it gets louder. I don't understand this. If anyone can fill me in it would be greatly appreciated.
That's the gain. It's backwards, really. You match voltage with the headunit like you were going to do in the first place. Since there is more signal going to the amp in a 5v configuration, the amp doesn't have to compensate for as much of a loss of signal, therefore it puts out less. On the other hand, however, if it receives a .2v signal (now we're talking oldschool!) it has to compensate for such a weak signal, therefore turning the "volume" up in the amp.