I've built several 3CX800A7 222 amps and the cathode circuit that was used
on the 8874 version was the same. The plate line changed.
Terry - W8ZN
-----Original Message-----
From: VHFcontesting [mailto:vhfcontesting-bounces@contesting.com] On Behalf
Of Bill Olson
Sent: Tuesday, October 20, 2015 12:00 PM
To: VHF Contest Reflector
Subject: Re: [VHFcontesting] 3cx800a 222 amp
Ralph, I'm really straining my brain here, but I seem to remember these
triodes wanted a little inductance in the cathode connection to "neutralize"
them. I remember with an 8874 on 220 back 35 or 40 years ago I build a home
made grid collet with finger stock.. The finger stock was in a solid ring at
first but in order to make the thing work I had to keep bending fingers away
from the grid ring on the tube.. That's all I remember, don't have that amp
any more..
Steve, W1SMS, now owns and runs Lunar Link, I'm sure he has the info you
want..
bill, k1DY
> Date: Tue, 20 Oct 2015 11:23:01 -0400
> From: mathenyr@marietta.edu
> To: vhfcontesting@contesting.com
> Subject: [VHFcontesting] 3cx800a 222 amp
>
>
>
> I remember reading that there was a K1FO 222 amp using a single
> 3xc800a7 tube. I have tired to get such an amp to behave without
> success...cathode circuit problems.
>
> Does anyone know if the K1FO amp description was ever published? Does
> anybody have one of the amps who could send me a copy of a manual or
> perhaps photos??
>
> Also looking for a proper grid collet for the thing...
> Eimac 720359 ... anybody know a source? The grid collet
> may be my problem, but I am on my second "hamstyle" version and
> getting frustrated.
>
> The 2M version of the thing worked first try....
>
> Thanks..
>
> de K8RYU
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