Reply to The audio interface in Mixtrack Pro

The Mixtrack pro has 2 RCA outputs of which I've used an adapter for and plugged a 3,5 mm plug into. The problem I'm having is bad sound quality and distorting when turning it up. My question now is if its the audio interface in the Mixtrack pro that sucks or if its the adapter that sucks? The sound I'm getting through the cue plugin is, however, working perfectly.