I've got the rackmount sansamp through the effects return of my boogie. It works but the sansamp has to be set to active and the volume level goes up and down and it gets a terrible feedback for no reason. Anyone else have this problem?
I haven't had that happen with my RPM, but I've only had it for a little while. Try running yours through a straight power amp and see if you still have a problem. you can also send Tech 21 an e-mail about it. They are pretty good at responding to customers' questions.