I have an early 80's Roland JC-120 and the tone is distorting/breaking up at low volumes with the distortion channel turned completely off. It essentially sounds like the distortion knob is set to 25% at all times. This is very frustrating because the only reason to own a JC-120 is for the totally clean sound. Does anybody know whether this is most likely damaged speakers or could this result from an internal electrical problem? It happens on all the inputs and I have tried adjusting all of the settings and used different cables and guitars. I have searched every gear forum and haven't been able to find any similar threads/comments.