I’ve upgraded my power amp to a Carvin DCM2000 and added a Boss RGE-10 EQ to the loop of my Model 100A Sustainor. I also added a Stereo Chorus module, which is hooked up in stereo (the Chorus/Delay is in mono). Also, as an alternative to modules, I can activate a SansAmp Para Driver for an alternate tone. It’s in the ballpark of a Boston 1976 tone.