[78-L] RCA dealers' phono?

Robert M. Bratcher Jr. rbratcherjr at yahoo.com
Thu Mar 10 22:15:05 PST 2011

One or two 50C5's in that transmitter? I built a cw transmitter out of a pair of 
50C5's once,  both used as a single oscillator made from two tubes. Later I 
built a 6AG7 oscillator driving a pair of 50C5's & got a few watts out of it on 
80, 40 & 20 meters. Modified still later to the 807 then the 6146b for higher 
power. I got about 60 watts out of a pair of 807's (didn't push them although I 
could have run 50 watts from each tube) & 100 watts out of a pair of 6146B's. 
That was about 25 or so years ago. Even built an 813 amp with 4 of those in it 
for 2000 watts. Way over the legal limit for a ham back then but I never stated 
it's real power over the air. Could have done the same thing with a 
single 4-1000A but didn't have one at the time.

From: Steven C. Barr <stevenc at interlinks.net>
To: 78-L Mail List <78-l at klickitat.78online.com>
Sent: Thu, March 10, 2011 11:31:36 PM
Subject: Re: [78-L] RCA dealers' phono?
Tubes with numeric designations (807, 1625, usw.) were usually
"transmitting" tubes...not used in home equipment. The #X# notation
appeared in the early thirties, replacing numeric designations
(although the venerable #80 rectifier diodes hung on...?!).
I also built a QRP transmitter using 50C5's...crystal, and
used leftover radio "tuning capacitors" and a hand-wound
coil (on toilet-paper "cores") in a pi-network configuration.
Actually worked a few folks on 40 meters...!

Steven C. Barr 


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