I'm using X8-H with external USB DAC: manufacturer: Head 'n' HiFi model: ODAC RCA compliant: USB 2.0 Full-Speed interface: USB Audio Class 1.0 bit depth: 16/24 sampling: 8/16/32/44.1/48/96 kHz chipset: Tenor TE7022/Sabre ES9023 It basically works, but the audio quality is severely impaired - occasionally (few times per second, randomly) there comes a 'pop' sound, clearly audible on certain audio passages (e.g. orchestra music). It doesn't happen on silent passages, loud passages mask them below audibility, but anyhow it's far from acceptable. It happens playing both video and audio files. It's the same with stock firmware and latest 002 beta 8 (not rooted). Player doesn't matter (XBMC/4K/MX player/ES player...), software/hardware decoder (with MX player) doesn't matter, either. ODAC connected to my PC works fine. As the X8 headphone output is not exactly audiophile quality, it's important to me (and hopefully others) to have an external DAC option. Didn't tried TOSLINK yet, but the bit perfect USB stream will be greatly appreciated.