On 1 Mar 2010 at 19:41, Tony Duell wrote:
Wit hradios, the difference in mains voltage was often
handled by an
aditional dropping resistor. This was commonly something called a
'line cord' which was a piece of 2 core cable with one wire being
resistance wire (!).
I've seen the same thing used for transformerless phonographs, but
the cord was 3-wire, with the resistance wire being used to drop the
filament voltage. You'd see this on "crystal" cartridge phonographs
with a 3-tube setup that included a 50L6, 35Z5 and a 12-volt pre-amp
tube (varied). It was a real puzzle seeing a 2-prong plug ending in
3 leads...
--Chuck