I just bought the mod factor a week or so ago and was finally ready to bring out my shiny new toy to a gig. I was using the Rotory function (my favorite) when all of the sudden this unstoppable feedback happened. I disengaged the effect thinking it was a freak thing and tried it again. A few ringing chords later…. Feedback hell… out of the chain it went. Any Ideas as to what is causing this and how to stop it? Or do I have a defective unit?