I'm interested to try the HDVD800 with my HD800, it's a very sexy looking unit and I'm very curious to hear Sennheiser's idea on the HD800. Many reviews rate the DAC as not that great but the rarely mention how the feed the DAC. I wonder if there is a difference between the USB and the spdif digital input? If anybody could bring me up to date on this I'd be happy, I didn't read through the whole thread. Thanks!