works great with a IV(I had one until Febuary..)the previous owner may have changed some of the internal settings-I dont have mine in front of me, but there are mzny different parameters (like vol level) that can get you in a place you dont want to be....once you get a hold on how to actually access these parameters, it gets easier...I would look into the settings in your "utilities" bank,check out you "effects routing"..do you have the manual??it took me a while, but I was determined to make it work-that is what it takes-what I do now after having it for 2 years is a simple setup....I have all of the tones I need on one bank, therefore its just like having a pedal board...I have another bank for trick stuff, but i have settled in to finding the 1 reverb I like..the 1 delay I like...the 1 mod I use...howeveer, it isnt near as simple as pedals!!!!