Left channel sounds louder

I had an experience like that with a CJ 16LS. I bought it used and at first the volume was fine...until I cranked it up past 42 on the stepped volume control. After a series of cable/component switching experiments, I confirmed it was indeed the pre and not something else. I called the guys at Conrad Johnson and then sent it in. $300 and some dollars later they replaced some volume attenuation parts and it's been happy trails ever since.