3 Dedicated lines into 1

I had three dedicated lines run from my main panel when my basement was finished. I am still getting some hum even after putting in cable ground loop break and plugging all my components (other than main amp) into a Monster power conditioner. All of these helped but I think the remaining noise is because the amp and Monster are on different circuits. Does anyone think combining these circuits to be on the same line would help? I know very little about power but it seems that I have read that this could be causing my problem.

I have also thought that having a seperate ground put in and putting all three of my dedicated lines on it might have a good result. Any thoughts on this?

Thanks