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...
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...