Kenneth Scharf 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

--
"C'est un Nagra. C'est suisse, et tres, tres precis."