Why do I only get sound on the left side of my headphones when plugged into the headphone jack on my Transactive Drummer amp? I use KRK KNS6400 phones and they work perfectly on all of my other equipment, including my DM10. Even when using the iPod dock that's built into it I get everything, drums and all, in the left side. Am I doing something wrong, or is there possibly a problem with the amp? HELP!! It's driving me crazy.