I had problems with my Friedman BE100 while switching channels via EXT Amp out (helix espession pedals got crazy ) , but made by myself one of those 9v powered relay switchers and now it works great. Anyway had to reduce voltage to 4V on 5v relays and it works great now :-).I've got some schematics if you are interested.. Also use moded CV out with help of tiny FED transistor (hidden in jack plug) , to switch my HBE booster on Friedman.. Also works great..