I recently purchased an M Box 2 bundled with Pro Tools LE7 as well as a Behringer B2 Pro Mic. Ideally im trying to record two channels, one DI and one mic. My problem occurs without the mic or the bass even in the picture. My setup would usually go as follows; I plug my bass into my amp, my amp has an XLR D.I output which I then run into the Mic input of the M box. In theory this should all work ok right? The problem is that my amp lets out this really high pitched whining sound. Its not incredibly loud but its just annoying, it shouldnt happen. Now this occurs with or without the bass plugged in and it only happens when pro tools is open. It is definately not the leads or proximity to any other devices as I have checked this. Any help for this annoying problem would be very much appreciated as I have spent a lot of money on this gear (well for me at least is was a lot).