I have an old Xtant 603x and it is behaving badly. There is something seriously wrong as I can hear the music (well, not really, just a distorted version of the sound) coming from the amp itself (without speakers)! What the heck is going on? I would think something is shorting/diverting the signal/output into the board? Grateful for input from those with knowledge on this type of stuff. Never heard this bizarre scenario in my life. TIA!