I found last night when I used my headphones and noticed that when the 990 is in upsample mode for CD input and the surround config is set in stereo to defeat the Dolby Headphone mode, I do not hear anything through my headphones. This doesn't happen in DH1, 2, or 3 mode with the upsample still on. Spoke with Outlaw's technical support this morning and found out that the upsample mode needs to utilize one of the headphone inputs namely the stereo mode which acts like a bypass to the headphones in order to work its magic. So in order to listen to music in stereo to defeat the Dolby Headphone mode, you need to keep the CD input in stereo mode not upsample mode and select stereo in the surrround config section of the main menu in order for the 990 to work properly. Thought I'd share this information for those using headphones like myself and maybe thought something was wrong with the 990. I can now breath a sigh of relief and not worry about having a defective unit.