Sub making sounds when radio off.

I have a quick question that needs some diagnosing.

I just installed a new amp to my sytem on Saturday. Ever since installing this new amp my subs make a thumping sound even when the radio is all the way down or turned off. What could this be?

I have no idea where to start looking. I checked the remote turn on and that wire looks good-nothing wrong with it. Should I check the RCA cables that I had to make in order to tap into the Bose system?

Any ideas?