From what I read about it, the XP has a switch that when turned on does not lose as much volume as the non XP units do when pulling the tone knob for added compression.
I want to find out how I can modify the RG80 I have to not lower the volume with the tone knob pulled. I hear all I need to do is put an eq in the loop and/or a boost pedal up front and it will do it, but I would like to mod it inside if I can find out how to do it right...