This is a sepperate issue concerning using external effects. The amp comes with its own external effects unit, however on connecting other external effects i tend to get a lot of background noise from the amp, especially if overdrive 1 or 2 is selected. I never use the effects send and return but then again what difference does that make from just plugging the unit into your normal jack input or would this be a better method to use? I wish to connect my Line 6 POD to the amp so am asking would it be best connecting to the send or return line or just plug it into the jack input?