my EH Qtron+ has this really nasty habbit, every once in a while, about 1 out of every 20 times i use it, it doesnt work, there's no sound, or very, very little sound. luckily, if i tap it off and back on it works totally fine. i've heard of this same issue with other EH fx....help! i'd love to know what's going on there and how to fix it. thanks.