Whew, I finally finished my mod. It took me long enough! Here's a quick breakdown of my mod.
Step 1 - breakdown
I disassembled the headphones, unscrewed the plastic cups from the headband, opened up the cups, removed the drivers from the cups, removed all the current cabling, and marked the left and right positive and negative on each driver (see photo above).
Step 2 - installation of new connectors
I bought a pair of Rean (Neutrik) Tiny 4-pole XLR chassis mount connectors, drilled holes in the bottom of the cups that fit the outer diameter of the chassis mount connectors, and installed them. The tricky part in the installation of the chassis mount Tiny XLR connectors were 1) I needed to find some spacers so that the pins didn't interfere with the drivers when installed in the cups, and 2) I needed to shave off part of the chassis mount connectors so the drivers sat flush in the cups. Once I had the XLR connectors mounted in the cups in the direction I wanted them, I soldered the tightening nuts to the XLR connectors (to keep from coming loose) and used a Dremel with a metal saw attachment to cut out a section of the connectors so that the drivers would sit flush in the cups. Then it was a matter of soldering some wire to the pins of the XLR connectors and then to the drivers (see included photo). Look for Audeze cable mod online for diagrams of the positive and negative pins.
Step 3 - reassembly
I popped the drivers in, replaced the pads, and screwed the cups back to the headband.
There are some minor details I left out to keep this from being too wordy like shrink tubing on the pins of the XLR connectors so they don't touch something and short. I also decided to spray the plastic cups matte white for fun. I think they turned out pretty good! For spraying plastic, follow good paint prep practice... sand, clean, prime (even if your paint says it includes primer use a separate prime coat), and let the paint cure for at least a week before assembling (even if your pain says dry to touch in 1 hour and ready in 24 hours).
I can't speak to any sonic differences because I had them apart for over six months! I don't have a balanced amp that can drive them yet either. They sound great with a stock Audeze single ended cable and my Valhalla. I'm building a Bottlehead Mainline that I know will be a fun combo. So far the DT770 600ohm is the best closed can I've heard. Although I've not heard the top end Fostex, Denon, or Audeze closed cans.