Just hooked up my Crown Xti-2000 to a Crown IC-150 pre-amp, and I have a lot of hum and some buzz. The IC-150 pre-amp outputs are going the Xti-2000 with an RCA to XLR cable. The hum is ridiculous. how do I solve this? I had and Onkyo M504 hooked up to the system just before I hooked up the Crown and there was no hum at all. Can I run the amp with nothing in the inputs just to see if it's the unbalanced leads going into a balanced inputs causing the problem?