[R-390] filament series capacitor can be risky

[Henry Mei'l's]

I  tried that approach with an receiver once  --  depending upon the phase point of the ac cycle, your
series capacitor could look like a short circuit at the instant of energization. Of course you could insert 
a time delayed startup series resistor, which then can be shunted out via a relay -- but this
seems rather over elaborate

I really can't see what's wrong with utilizing the existing 12 volt transformer tap or the notion of inserting a plug-into ballast tube socket, regulator unit.

Also, regulating mains/power line ac input sounds like a good idea but requires a rather bulky
and sometimes expensive outboard ac magnetic regulating unit. I suppose you could have some ac to ac
electronically regulated converter circuit to regulate your ac but isn't this another overkill?

Henry OZ3O N2NR