PreAmp Gain and Impact on Amp

I am not sure about the "load on amp". But it will impact the sound from your speakers - BIG TIME. I recently experienced this in my system. I used XLR to get a substantial gain from preamp to amp and the difference in the bass/mid-bass notes is nothing short of staggering. Like going from a thin cord to a thick rope.

It has nothing to do with load. If you feel that it's not enough gain(usualy you'd have to use the most of your volume control dial), you can either adjust it if possible or purchase different preamp.

Sufficient gain is as important as fuel delivery from fuel tank to the engine: poor fuel delivery will lack pressure and acceleration while rich fuel delivery will increase fuel consumtion but increase high-speed and high-rpm performance.

You need to 'fill up' the input of your amp with preamp making sure that output voltage with gain set to zero will deliver sufficient voltage for the full power output of your amp.

It's all usually written in specs tested at 1kHz: Output Voltage, Input Sensitivity, etc...

If you have the volume max'd, you don't have enough gain. If the volume control sits near the bottom, you have too much gain. The idea is to have just enough gain for adequate listening levels and a bit extra for that party and your son to blow the speakers. For less than adequate speakers, volume control and distortion control are fairly synonomous.

Some sources have an internal switch to raise output voltage, which is the same as more gain.