[AMRadio] Re - response to input to screen grid amplifier
Bob Bruhns
bbruhns at erols.com
Wed May 24 11:13:19 EDT 2006
Bill, assuming you want to use it as a linear, you should keep it as-is and work out how it is producing control-grid current like
that. I have to think that the screens are tied to the control grids somewhere.
Bacon, WA3WDR
----- Original Message -----
From: "Bill Fondren" <bill.fondren at sbcglobal.net>
To: <amradio at mailman.qth.net>
Sent: Tuesday, May 23, 2006 5:04 PM
Subject: [AMRadio] Re - response to input to screen grid amplifier
> Thanks for the quick response to my questions concerning this amp. John, I was ready for some salty remarks (hihi) and I did
clean my glasses and take a second or third look at the thing. I thought I had missed something since going to USAF Radio School in
the early 50's. Guess that tells u why I mess with vacumn tube rigs. Anyway thought I better get some expert opinions before
starting to cut and chop to get it to a more conventional type. The construction of the amp is above average for a homebrew rig. A
couple of other things There is a RFC choke coming off the G1 connections going to the 10K resistor then to the grid meter
(0-30ma shunted with a 50 ohm 10 watt resistor) It does read about half scale peaking normal as u tune the grid circuit. Also a .01
bypass cap at the meter. The input coil is grounded in the middle through a RFC choke making a double coil, tuned by a split stator
cap. One of the tuned circuits goes directly to the screen grids and the
> other feeds the neutralizing voltage back to the input from the plate. No bias circuits of any kind. The few times I used it I
got good reports using a Elmac AF-67 exciter. Will probably change it to a more conventional type. Thanks again Bill K5PML
>
>
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