I was listening to voivod and I swear I heard a guitar part gradually changing reverb level from none to full to none to full etc. Kind of like panning stereo in a way. I just got a pb&j and may add an expression Jack for level which would sort of do the trick, but would prefer to have it done by flicking a switch. Any ideas on how to accomplish this live, without physically turning a knob?
You'll want to vary the level with an LFO. The topic has been brought up here before (modulating paramters via LFOs), you could search for H11F3 as I think it's probably come up in every such discussion!