Okay first of all I need to warn you. If you think this module just outputs a line level signal. NOPE! I just needed something to get the signal level down and being able to connect my junk headphones to. I never had any problems with either them (Teufel ANC 1st gen) or my old Roland Cube guitar amp. I misused part of another module from eddie bermans page for that: Link

Again it works fine for my purposes, but it is far from foolproof.