Well, I bought this so that I could do swells into my ar20dlxl and replica. First off, I didn't realize that because it is optical, there is no way to turn the pedal on or off. Second, I am not sure how to find unity gain, i.e. find volume level that my tone would be at without the pedal on. It seems to cut the midrange out just a hair, but I don't mind. Overall though, I will have to mess with it some more, because I only bought it to do swells, and I am not sure it does that function well enough to keep it.