This is a fairly thorough demo of this excellent compressor. It is NOT a Dynacomp- or Ross-type design, though I'd put its sound in the same neighborhood. The design uses an LM13700 (a dual version of the CA3080E was used in the Ross/Dynacomp), which is an extremely low noise chip, and dual op amps chips (again helps with noise).
I really like this design -- it's almost as transparent as an optical compressor but can get "effecty", it's cheap to build and doesn't use a $5 chip (that isn't really that good), it's pretty quiet, and it's versatile. It's the first thing I've heard that really had me considering taking the Orange Squeezer (my "always on" pedal) off my board.