
Grummy, that resistor will be a 440 K.
Looking over the schematic, I'm a bit confused. I'm not seeing provisions for a power supply, so should I assume you're using passive banana technology? Very old school. Just be careful of potassium electrolytic discharge. If you switch out to an active banana, I’d try to find some sort of latex sheath, and wrap it tight before I used it. A lot less clean-up should it blow.
Or you could just shunt it to frame.
It's good that you have the smoke reservoir in the circuit. Once the banana discharges, it gives the circuit time to recharge.
Again, very old school.
If you want to further tune the engine, I'd suggest an audio taper pot.