This seems to be the input stage of a TS9 glued onto a simple op amp buffer. I drew up a schematic based on what Analog Mike stated. It might not be exactly what he's doing, but it should get you pretty close.
http://i.imgur.com/VxxChoB.pngNote that the original transistor used in the TS9 was the 2SC1815, but a 2N3904 can be substituted without problems. I do keep a small stash of 2SC1815s on hand due to their weird pinout.