Just purchased a NAD T763 three months ago. Went to explore the listening modes as listed in the owner's manual. However, the receiver's listening mode is stuck on stereo. Is it the cd's I'm playing? I don't think that it should matter. Has anyone run into this problem? I am pretty sure I have the system set up correctly. I have flipped through the listening modes once before when I first received the receiver. Any help would be greatly appreciated. Thanks in advance.