If I have Low, Medium and High gain settings in the pre-amp - but Low is too low and Medium is too high - how do I get what I want? Is that a function of pre-amp volume?
 
Thanks - rev

Most pre amps have a gain nob you can turn. If you share your specific preamp, I'll try to help more.

>Most pre amps have a gain nob you can turn
The Roland GP-100 - doesn't have Gain but does have Volume in the pre-amp section. It could be a misnomer on their part.

The user manual shows an input level nob on the left on the device. This didn't do the trick?

You can read the manual. The gain setting for your outputs should be set to match what you are sending them to. The volume before your eq looks like a staging volume for the eq and the master after the eq the most likely to effect the output level.

No, input level knob doesn't affect the amount of crunch in the pre-amp. It only makes a quiet input signal louder. This might be a terminology issue, Gain is not the same as Volume to me. Gain cranks whatever you're tinkering with (distortion, a frequency range, a transient peak, etc) and Volume makes the collective, final result louder. 
 
I think, in this context, Volume is used to mean Gain in the pre-amp section and Output is supposed to be the final volume.
 
 
 
 

When it comes to Pre-Amp's Gain often refers to input value. On guitar amps you use it to heat up your tubes and get some distortion. So, for your purpose, Level which controls signal into your eq will heat it up before eq processing. Master Level is on the other side of your EQ and handles what is sent to the outs...
 
http://www.rme-audio.de/forum/viewtopic.php?id=1102
 
I found this nice topic that will help to demystify your output reference levels.

gswitz:
 
The discussion at you link is a tad off target because it's about matching input and outputs with other gear and for specific purposes. My question was more about getting the amount of crunch you want on a particular guitar sound. If the preset increments (Low, Medium and High) are not quite doing it for you, what do you do?
 
The answer I think is to choose the closest setting, Low for example, and then add more crunch using the preamp Volume control. Roland, in this case, seem to be using Gain and Volume to mean the same thing. That was really the source of my confusion. It's an older unit and terminology probably didn't matter as much back then. The decision to call it Volume instead of Gain might have been a marketing decision, more people know what volume is!