Just got a SYB-3 today from GC. It's working fine out of the loop with and without other pedals. When I run it though the loop however, even by itself, nada. I get perfectly good bass sound when the pedals on and off so I know the signals going through the pedal yet there isn't any effects. Again, it works perfectly fine out of the loop, effects and all. This is frustrating and annoying as all hell. Any idea what it may be? Anybody with the same issue? I'm running a Warwick Corvette std into the pedal into a Fender Rumble 150. Maybe my fender rumbles effects loop can't handle it? I don't know. Never had any problems before with Boss products and I own a lot. If it helps at all to diagnose the issue, when I play hard, a very loud distorted buzz can be heard. Checked the SYB manual, nothing.