hi. my treble knob developed this little problem. when i roll it all the way up and conversevely all the way down it stops (like all of them) and then if you try to roll it more it will do but with this jjjjjjjjjjjj sound like something is loose or scratchy. HEAR ME WELL. its not the sound being amped, so its not the typical jjjjjjjjjjjj when you dial with the potencimeter. cause my problem is not amped. at this point it is ok. is just that at the top it gives you some more movement but with this jjjjjjjjjjj sound. any answers?