[pr0xZen]

For a TV/repeater/AVR etc, to do bitstream passthrough to/through anything other than another HDCP certified device and connection - is in strong breach with HDCP licence and compliance rules (HDCP Licence agreement, Exhibit C - Compliance rules, paragraph 3.3). SPDIF/toslink - optical or coaxial connectivity - cannot be HDCP verified as it does not have the bandwith for encryption, nor the tech for handshake and key verification.

AC3 and DTS can go over SPDIF. These are encoded yes, but not encrypted. The TV, however, receiving the signal over a HDCP connection like HDMI - cannot passthrough this to another device, unless this is also over a HDCP enabled and certified connection. There are some TVs out there that claim they can output AC3 over SPDIF. For this to work, it would be highly dependant on the signal source and connectivity (most likely NOT a HDMI source).

I have experimented with "forcing" a DTS signal to TV for SPDIF passthrough. 2 different results: Either it fails at the source (video playback is garbled/choppy/doesn't play/player crashes etc) - or you get a HORRIBLE and loud "static" noise out.

If you need SPDIF connectivity, you'll need to take this straigth from the NUC to the AV receiver. I am also in this boat (my AVR does not have HDMI connectivity) - and I have had large success with this USB sound card: http://dx.com/p/15746
The Cmedia CM106 is quite a decent DAC, at a very affordable price. This unit also has 5.1 analog outputs if needed (You can have XBMC do software decoding, outputting HD audio over analog). Added bonus: Its one of the few cheap usb solutions that has updated drivers, including Windows 8.1 drivers ( http://www.necacom.net/index.php/cmedia/...8-0-8-2163 )