I'm hoping that someone has solved a similar problem as I am having running my (Line 6 Bass Pod XT Live) multi-effects pedal into my (Marshall 450h) head. First, the effects I use regularly are all set to roughly the same output level. When I plugged the multi into my amp's front input jack, the signal was feeding back both from my stage amp, and the monitors/FOH as our soundguy was taking the line out from my amp. Second. That was Friday nite. Saturday nite I tried something different. I re-adjusted the outputs on my effects even lower and instead of running to my input jack on the head, I used the effects return loop on the back. My on stage sound was 100% better, but...there was no signal output from the (xlr) line out, nor did any of the 'front panel controls' (except master volume) work. What gives? Is this normally how an amp works? If you input from the effects return only, the line out is defeated somehow? Please help me!!!!