Motu 896hd Main-out Problems Options

[oxzone]

Hi to all! I've buyed my motu in december in a New York store (i'm Italian and I live in Italy). Since some days ago, I didn't ever use the phisical xlr main-out so I' didn't ever discover that from that connector the sounds plays with a lot of distortion, and some (tension?) noises. The other analog outputs and the headphone out plays good. I've tried with some different cables (xlr and firewire) and different software, os and computer. Did any of you ever heard about this prloblem? Thank you!
Ale.