The Asus Xonar U3 USB DAC has a S/PDIF-Out port.
The inexpensive Asus Xonar U3 is on the list of USB DAC compatible with the Samsung Galaxy Note 3.
http://www.head-fi.org/t/595071/android-phones-and-usb-dacs/5910#post_11145853
"In addition, Xonar U3 also offers a Hi-Fi mode for hi-fidelity playback without any effect processing to keep the original audio fidelity."
http://dlcdnet.asus.com/pub/ASUS/Audio_Card/Xonar_U3/E7803_Xonar_U3.pdf
The Xonar U3 is compliant with Dolby Headphone virtual surround sound.
It can be used with a Virtual Reality headset + smartphone to create an immersive cinema / concert / ... surround sound experience.
http://www.head-fi.org/t/595071/android-phones-and-usb-dacs/5940#post_11158898
5.1/7.1 multi-channel Dolby Digital/DTS audio-video file > VR audio-video player running on Android smartphone slotted into a VR headset > 5.1/7.1 multi-channel PCM stream > USB audio out >> Asus Xonar U3 with Dolby Headphone virtual surround sound engine >> headphones
A headset with USB output: Cmoar personal smartphone viewer
https://www.kickstarter.com/projects/706938033/cmoar-personal-smartphone-viewer
The current Samsung Gear VR:
. only AAC and MP3 for the time being
http://forum.xda-developers.com/showpost.php?p=57677027&postcount=3
. only Galaxy Note 4 headphone out