I'm still on topic since one of the posters claimed the 75's sound much better with a cmoy!
Most CMoy's are probably found on ebay these days. Do a search for "headphone amplifiers" and you should get 4-5 pages that include several listings for CMoys. Some have their own websites and can be purchase directly outside of ebay.
The real key to a CMoy is building one, however. The defacto standard tutorial for that is on Head-Fi user and famous DIY-er Tangent's site:
How to Build the CMoy Pocket Amplifier