100+ Head-Fier
Pros: Awesome balanced sound, with enough bass to kick without being boomy. DAC Works natively on iPhone through lightning, Android, PC and Rasbperry Pi!
Cons: Cables are a bit stiff and thick.
Built in Headphone DAC and amp sound great and work with everything I can throw at it. 
Plugged into the Pi2 USB port on my custom battery powered portable 2TB SSD Pi2 running JRiver Media Center 21.
JRemote on iPhone for control of Media Center 21.
The Headphones DAC does up to 192/24 and also does DSD 2.8Mhz and 5.6Mhz on PC and yes even does DSD on the Pi2!!!
With the native iPhone lightning connector looks like it down samples to 44.1/48 16bit.
7 hours battery life.
The Pi2 can effortlessly push SACD ISO DSD and DSF files to the headphones built in DAC plugged directly into the USB port of the Pi2.
Best part, plug and play - no special setup.  :)

No more messy cables and external dacs/amps. :wink: (was using FiiO E17 previously)
AND best of all no more down conversion necessary, play every 2 channel file natively to the headphone DAC from the Pi2 usb port!  :wink:
(using JRiver MediaCenter 21 for Pi2 with JRemote on iPhone or Android for control)

i.e. The DAC supports all the below with no down sampling playing back from the Pi2 via USB.
16, 24 and 32bit.
DSD64 2.8Mhz
DSD128 5.6Mhz
The Pi2 can decode and transcode DSD files to 352.8 PCM to the DAC in the headphones via USB without raising a sweat. (well it is working pretty hard but not skipping!)
This below is DSD to PCM (just worked out how to get native DoP - first time with a DoP capable DAC)
JRiver Media Center 21 running on the Pi2 decoding DSD to 352K PCM direct to the headphones.
This is native DSD DoP 2.8Mhz using 3 cores for decoding.
JRiver Media Center 21 running on the Pi2 decoding DSD to DoP direct to the headphones.
They also work on the Samsung Tab 3 8" I have. :wink:
They do 192/24 on the tablet through JRemote. :)

When plugged into the iPhone, JRemote shows 192/24bit but the specs for the headphones say they are limited to 44.1 & 48/16bit on iPhone.
Maybe it's downsampling in the iPhone or maybe they mean with the native Apple Music player?
I know using my other FiiO E17 DAC on the iPhone that the iPhone definitely supports 96/24 with JRemote.
The headphones PC cable also works through the iPhone camera connection kit. (showing 192/24bit in JRemote)
Giving them a good workout. Realllly nice sounding headphones, the built in headphone AMP has heaps of power and is clean and punchy and the bass from the drivers is full but not bloated, the mids are really present and the highs are very clear without being tedious and too bright. Great imaging, space and separation. These are easily my favourite headphones out of the Senn HD600 and Klipsch Image Ones. The build quality is awesome too, strong hinges, no fragile plastic on these bad boys and they are super comfortable.  
In comparison the Image ones lack detail and have an exaggerated sloppy bass, and the HD600's lack the punch and power in the lower octaves and don't cut through as well at the top end.
Last one.. Here's a 24bit 96k file being upsampled to 32bit 384K on the Pi2. Wow!
Does any current owner know if it is possible to plug balanced wires to the MDR-1ADAC?

"Regular" MDR.-1A are compatible with balanced wires, however, Sony does not state the same about the MDR-1ADAC...
it is possible! as 3.5 mm female jack has balanced conection (5 pole). but you need to make a little mod. as second ground in jack is used in internal circuitry for automatic disconection of DAC in case of pluging the standard 3.5mm audio jack. you need to take this second ground and place it back, but at the same time maintaining the good function of DAC
i mounted an external switch (with 3 pins) to bypass this .

p.s. if you hear a noise when switching a song, this is not true balanced.