On 12/11/2011 10:11 AM, Scott Dorsey wrote:
Kenneth wrote:
Interesting minimal rig. The voltage tripler supply looks a little
fishy, there should be three diodes in a tripler (the two in series
count as one), though he DOES have three capacitors. I would use a
power supply with a conventional full wave rectifier myself. I guess he
was limited for space. Still the transformerless supply will be safe if
the chassis is grounded to a true earth ground and the hot side is
fused. (Might have a bad hum problem though).

Hot chassis supplies were very common back in that era, and most consumer
television sets and radios continued to be hot chassis well into the
seventies.

My first transmitter was hot chassis, just a 6L6 with cathode keying
and a first-order bandpass on the output....
--scott

I recall an article about a 1KW 80 meter linear using 10 1625 tubes in
parallel (might have been 9 in parallel with one as a driver) with the
heaters wired in series and a voltage quadrupler power supply operating
off the AC mains (120v).