Are you refering to the 70's version or one based off of the 70's version.
The reason I ask is b/c I could only get my hands on the 70's version schematics and taking a look a quick look at the schemo's it seems like There is only a Volume, Bass and Treble control, while the newer version has controls similiar to that of the MTS modules (Gain, Bass,Mid, Treble, and Volume).
Since I only have schemo's for the old version it seems that the Clean, Blackface, or DLX are the closest as far as structure. However there seems to be a good bit of work.
Good Luck and tell us how it goes...