Ever since I bought my ATH-M30s, I've had the annoyance of the stupid jack on the end, which is one of those where a 1/4" jack screws over a 3.5mm, and have been planning to upgrade to a modular, xlr-based system.
When roaming free on studiospares the other day, I finally took the plunge and bought the bits to do the upgrade.
After a quick bit of soldering I ended up with a pair of cans with Sommer goblin going to a black (because they're nice) nc3f, and three cables to allow this to be plugged into minijack and mono- & stereo- jacks.
The next stage is a nice little flight case to house the 'phones and adaptors, hopefully with a little headphone amp built into the lid...