31 Aug
2008
31 Aug
'08
10:42 a.m.
On 31 Aug 2008 at 13:19, schwepes at moog.netaxs.com wrote:
Back to the 1951 ARRL, the device was called a
'monitone' and used
a 6SL7 with a phone jack on the one grid and the output of a
6J5 on the other grid after biasing and volume control and an
osscillator that used a neon bulb a capacator and biasing
resisters. Transmitter input was to 6J5 and effectively to side one of
6SL7 through another resister. If I could draw in ascii I'd
show this device.
Nope, not it. It was definitely a CPO and not a monitor. Single
tube, no neon bulb, line powered via a single 6.3v filament
transformer. As I said, it may not have been from the RAH. But I
built and used it. I suppose I could reconstruct it with parts from
my hellbox if anyone was really curious (I think I still have an
interstage audio transformer kicking around). I think Roy nailed it
though when he suggested a blocking oscillator--one doesn't require
much gain to work.
Cheers,
Chuck