Fountainhead

Hi JCarter,

1 volt should be enough to drive your power amplifier to full power. BUT, and a big but, is what is the sensitivity of your power amplifier input? Most power amps have a pretty wide range with the input sensitivity adjustment, about 3-4 volts down to 300 millivolts (3-4 with level of power amp to minimum sensitivity, and 300 millivolts with power amp input level set at maximum). It's best to start out with the receiver at a nominal level say if your receiver will go from 0 to 50, then set the receiver at say 25 and then turn the power amp (with clean music -CD preferred) up until you hear distortion, then leave the power amp adjusted and then turn down the receiver, then go to an "Auxiliary" input and listen to the background hiss, if it's really loud then turn down the power amp a little. It's a gradual process. You should be able to find a happy medium adjustment for your setup without resorting to extremes on receiver level or power amp level.
But, if you have 4V preamp output on your receiver, then you'll get more voltage with less turns of the receiver level knob. Before "6V" or greater receivers became popular, everyone somehow got by with 1-2 volt outputs and the same power amps we're using now (but in older packages, haha). 95% of AB power amplifiers (most of what's out there) are still using the same switcher IC in the 12v DC to DC convertor, and the same output transistors and just repackaged them in new chassis.
Now, the mini amps that use Class D switching are neat little packages, but basically have a DC to DC convertor and Class D outputs.

I would recommend you ask BigAudioFanatic, I'm sure he has all the popular receiver/amplifier combinations settings memorized.