Thanks Jeff... now if I could find out the values of the resistors. I'm guessing 22k, but not sure. Maybe someone will know.
What I'm trying to do is add SUB INs to my M-216. Believe it or not the M-200 series does not have them for the 4 busses, only the stereo buss. The 106 and 208 appear to have a lot in common, so I thought it would be a good unit to reference.