I just bought a Crown XTI 1000 power amp to use with my Ashdown preamp. The full range output on the Ashdown pre is a 1/4" phone jack. The input on the Crown is XLR. First I tried using a 1/4"-1/4" instrument cable with an impedence matching transformer adapter to convert to XLR. It worked, but my output level was really low. Next I tried a 1/4"-XLR shielded patch cable. It has the stereo-like plug with the extra ring on the 1/4" phone plug. It buzzed and the level was really low. I tried two of them, both brand new. As a test, I plugged my bass into my mixer and ran an XLR-XLR cable from the mixer to the Crown. No buzz and it was crushing loud. What am I missing here? Seems like the level coming off the Ashdown preamp isn't right. Is there some other cable I need?