I have not had any experience with compression boxes until I bought one for my daughter's guitar. The box in question is a DOD FX 80-B. I tried it on bass and fooling around with the release and compression pots I seem to hear a slight difference in tone. The problem is, the difference is so slight that I could be hearing a gain difference with the box engaged and notheing else. What should a be hearing with a box like this? Is anyone familiar with this particular unit? Mind you I don't hear much in using it with guitar either...Reveiw wise lots of folks like it. Thanks.