Meizu MX 4-Core: an Android-powered smartphone with 24/192 SPDIF audio out capability
http://www.innerfidelity.com/content/sound-smartphone-meizu-mx-4-core
"In the past, I've lamented how there are very few portable devices that can supply a digital signal to feed a quality portable DAC/amp unit like the
Leckerton UHA-6S. Meizu comes to the rescue with support for SPDIF output. Unfortunately there is simply no room for a dedicated jack, so Meizu did the next best thing---MHL output through the microUSB port.
MHL is actually an industry standard that supports HD video and digital audio out, and is typically used for connecting a smartphone to a display (using an MHL to HDMI cable). The Meizu MX is the first and only device I've seen that also does SPDIF audio. There's an option in the settings menu to enable this output, and it requires an adapter to interface with a coaxial SPDIF cable.
Meizu hasn't quite finalized their plans for this adapter. For now I'm using an engineering sample of a breakout board based on the Prolific PL-2303X USB to serial bridge controller.
Keep in mind that this is not converting USB to SPDIF but rather controlling the native data that already exists in the MHL output. This sample board has a microUSB connection that plugs into the phone itself, 3 miniUSB ports, and a coaxial SPDIF port. It's small enough to where I have carried it around with the phone and the Leckerton as a portable rig, but of course there's room make it smaller by ditching a lot of those ports on the final version. I imagine Meizu could do a typical home dock with HDMI, SPDIF, and analog audio outputs, and then also a small inline cable with just SPDIF to be used in a portable setup.
The best part about this output is that it spits out bit-perfect data. I've tested it with various DACs and they all confirm that the Meizu plays back an unaltered stream, ranging from 16-bit/44.1kHz CD standard tracks to 24-bit/192kHz hi-res material and everything in between."