Bel Canto left channel cutting out with distortion

I am hoping someone can give me advice in regards to my Bel Canto eVo2i GenII integrated amp. I bought this amp used about a month ago and for the first couple weeks it worked perfectly. Last week I changed all my cables, and for the first time, hooked my CD player up using Balanced.

At first, I did not have any problems. Then one day while doing some listening, out of nowhere the left channel cut out and became heavily distorted. At first I thought it was the tube in my CD Player, so I replaced them. No fix. I made sure the speaker cables were secured and tight. No fix. Then I unplugged the XLR from the back of the amp, and plugged it back in. It began to work again... This occured about three more times within a few days (The problem seemed to be resolved after unplugging/replugging the cables multiple time), then worked fine for a week straight.

The other day it went out again, and is out for good. No matter what I try it will not come back. The reason I think it is the amp is that if I switch the L and R cables only at the amplifier end, it always stays in the left channel. I know for a fact the right channel from the CD player is working, because it works in the R input on the amp. So this must be an amp issue right?

Also, since this has been happning. When I turn the amp off using the rear switch (Not standby) there is a huge thump/pop when turning the unit back on. I am afraid it is going to ruin my speakers. It never did this before...

Any info on what this might be? I talked to Bel Canto and they quoted me over $900 after shipping and labor to replace the Amplifier Board (if this is the culprit).

I live in Orange County, CA. Are there any local techs that can solve this sort of problem?