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Re: [Amps] 813's

To: "Vic K2VCO" <vic@rakefet.com>, <amps@contesting.com>,"Chris Pedder" <chris@g3vbl.co.uk>
Subject: Re: [Amps] 813's
From: "Ed Swynar" <gswynar@durham.net>
Date: Sat, 27 May 2006 17:29:59 -0500
List-post: <mailto:amps@contesting.com>
Re. ANY horizontally-mounted tube, the trick is to ensure that the expanded
filament (expanded due to heat) doesn't sag down & short-out against the
grid...

Warnings about aligning pin "X" & pin "Y" in a vertical plane are fine for
U.S.-made tubes, but the Chinese tube makers --- in the early days,
anyway --- didn't necessarily adhere to the physical lay-outs prescribed by
the designers, as the American manufacturers did.

It's best to physically look at the innards of the tube and orient it such
that the flat of the plates is vertical when the tube is on ts side, or 90
degrees relative to your chassis, irregardless of pin-outs...

Not sure if that makes any sense, or not, after I re-read it! Hi Hi. I hope
you get the picture, anyway...

~73~ Eddy VE3CUI - VE3XZ


----- Original Message -----
From: "Chris Pedder" <chris@g3vbl.co.uk>
To: "Vic K2VCO" <vic@rakefet.com>; <amps@contesting.com>
Sent: Saturday, May 27, 2006 3:32 PM
Subject: Re: [Amps] 813's


> At 19:45 27/05/2006, K2VCO wrote:
>
> >There was an article in ARRL handbooks of the late '50s or early '60s
> >describing a series of single-band amplifiers each using a pair of
> >813's.  Construction was simple, with a pair of chassis behind a short
> >rack panel and the 813's mounted horizontally.  The author left the
> >plate voltage connected and just lit the filaments (and I presume
> >switched drive and antenna) of the one he wanted to use.  I built a
> >similar amplifier, although mine was for 80-40-20 meters.
> >--
> >73,
> >Vic, K2VCO
>
> The ARRL publication "Single Sideband for the Radio Amateur" Fifth
> Edition 1970 also has these amps on pp138-141.
>
> Chris G3VBL
>
>
>
>
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>


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