Left channel sounds louder

I'm going to look for a couple of test CDs I know I have laying around to perform a tone test. I don't know why but something tells me is the preamp. I'll get back with some results tomorrow since tonight I have my daughter. Thanks for the advise.

Well, Just like I thought, the preamp seems to be the culprit. I switched the cables at the amp end and the sound also switched to the right channel ( louder ). I need to contact the distributor now to set have them look at it. I'll post the results at a later time.