Can't remember where, bu I've seen some threads about drilling through the Belton plastic to remove a resistor to get rid of the modulation on a BTDR-2, but maybe there were some threads on the 3H as well. Why not throw it on a switch?
Anyway, here's a Madbeaner who removed the BTDR-2 casing entirely
"...removed the resistor going from pin6 of the last PT2399 in it to the lfo. So now I have a NON MODULATED BTDR2!!
" — Boba7
Boba7 also made a few other mods to the brick/moodring, hit the link if you're interested.
I look forward to your and Robert's findings...