Hey all, I am playing through a Laney Vc50 2x12 tube amp (which I have setup with 6 12ax7`s and 2 el34`s). I just bought a Boss Me50 multi effects unit, and every now and then, when playing on one of the Boss` distortion features, there is a weird feed back from my amp, that sounds almost like a reverb of sorts...I thought it was originally a problem of frequency, but after adjusting my tone (the problem went away) but soon returned...Any clues as to what is causing my grief.