P-Series Valves, what to do with them?

[ppppenguin]

Andy, thanks for doing the simulation. Any chance of doing it with a resistor whose resistance is comparable to the reactance of the cap?

I don't see how a capacitor can act as an approximation to a constant current source. Unless its reactance is substantially greater than the load resistance. If the reactance of the cap (or resistance of the dropper) is fairly large compared to the heater chain then it will indeed approach being a current source. But that isn't what's normally happening in a real life heater chain.