Based on a tip from the facebook forums, I compared adjusting the volume in the amp section as opposed to the rig volume.
While the rig volume simply increases volume, increasing volume in the amp section seems to "tighten up" the tone a bit.
Anyone know why this is? Presumably it's something to do with how the signal feeds into the cab section? Like it "drives" it a bit?
The manual doesn't explain this, in fact it seems to suggest that the volume in the amp section is no different from the rig volume:
"This parameter can be used to balance volume gaps between different PROFILEs. The Rig named “Crunch”, which
is default in all Slots in Performance Mode, could be used as a volume reference."
However, try it yourself - there's definitely a difference in tone if you boost volume in the amp section.
Anyway, if it sounds good it sounds good and all, but just curious to know why this volume control affects tone - is it modelling something in particular (i.e. tonal changes in a real cab due to amp-head volume) or is it just an incidental consequence of a digital signal feeding into the amp section?