My latest addition - Radialva Groom

[Yorkie]

if you are going to use 110 volts i would maybe reconsider a resistive dropper ie one of the metal clad types.
rob t

Good point Rob - with only 34V to drop the wattage will be quite low. I recently used metal clad resistors on the Portadyne Princess and look-alike 'Noble' TRF sets on which the mains droppers had burnt out. Metal clad resistors must be de-rated if not mounted on a heat-sink as they will not dissipate their stated wattage if not heat-sinked. I just used a piece of 5mm thick alloy angle as a heat sink, which worked out fine. Although I calculated the total dissipation to be about 23 Watts, I used 50Watt resistors rather than 25 Watt ones, as 50W ones are only about 2.5” (6cms) long.

See: http://golbornevintageradio.org/forum/sh...p?tid=2154&highlight=Portadyne+Princess