Re: Philco Mystery Control

"norml" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> My understanding is that the filament voltage is applied as soon as
> the dial is moved off the stop, giving the tube time to reach
> operating temperature by the time the dial is released. Only the plate
> voltage is pulsed.
>
> I also seem to recall that the filament is slightly over-voltaged to
> shorten the warm-up time.

On the website http://www.philcorepairbench.com the operation of this unit
is discussed. Looks like it takes a combination A-B dry battery pack giving
45V on the plate and 3V on the filament, which is more than the 2.1V it's
rated for. The schematic is there; does it look as though there's anything
in there to knock down the voltage, or is it really getting 3V?