I recently purchased a dbx 386 tubbed preamp to boost my recording signals to my SB Audigy B800 platinum. The preamp has spdif out so I am using this via RCA cable to the spdif input on the front of my sound card. I am recording with Adobe Audition. For some reason I am only getting a mono signal through the spdif where I get a stereo signal through my other inputs...Any suggestions ??