tricky to explain...been using the unit since last august , both live and studio with couple of glitches but nothing serious, and yesterday when editing a preset, (and subsequently all of my user made presets, and factory presets were effected by this) only a reverb pedal, or delay pedal became the controller for volume. If I took these out of the chain, there was no volume at all. So all of my made user presets has to have either of these two (reverb, delay) on. I could take most the intensity practically of both and get a sort of sound. Exactly the same with factory presets. no sounds, or really limited especially if the preset has reverb already aligned within the preset. hope this helps