[morzh]

OK, no such luck.

Here's why. The tubes a 100mA and the summary of the volts is 20+20+50+60 is 150V. Which makes 120V insufficient. It will probably work, but not well, as the filament power will drop almost twice (150/110 square) or a bit les than twice but still a lot at 120V.

The resistances are thereby 1.5K plus 700 Ohm is 2.2K, which makes exactly 100mA at 220V.
Without the autotransformer I cannot bring the voltage up to 150V for the filaments.

I of course could do this: use 50+60 and a small resistance, and parallel that with 20+20 and a capacitor. But this is a lot of rerouting and I do not like rerouting things like it.

Thinking....thinking.....

I need overall impedance of 1,200 Ohm. The tubes are 400 Ohms together. I need 1.13K equiv. cap in series with two tubes with 20V filaments. This makes for 2.34uF cap.