[Collins] Tube Shields Needed

Sat, 14 Dec 2002 14:29:48 -0500

Tube shields, especially the "bayonet" style that are commonly found on
mil-spec and commercial gear are there for two reasons. The first is to
insure that the tube stays put. Vibration and  hot-cold cycles tend to
loosen tubes from their sockets and we all know what that does. The second
reason, which is only sometimes at issue is for electrostatic or
electromagnetic shielding purposes. This is mainly critical on RF front ends
as well as audio input circuits. The main dis-advantage of using shields, is
that they greatly inhibit heat dissipation, with the result of shorter tube
life.
In many applications ( the R-390, and other Collins sets leap to mind ) many
of these shields can be removed with no ill effects on performance.
Chuck N1LNH
----- Original Message -----
From: "kwylow zinjanthropus" <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Friday, December 13, 2002 9:38 AM
Subject: Re: [Collins] Tube Shields Needed


>
> Hopefully this is not a dumb question. What is the purpose of the tube
shield and what benefit will it have for the 75A4? Just asking and thanks.
Cal, N6KYR
>  Roger Shultz <[email protected]> wrote: I am in need of two different
tube shields for a 75A-4 restoration project.
> The first one which I need is one (1) for the 6BA7 which is a 9 pin tube
and
> the shield measures 2.5 inches high. The second shield is the short 7 pin
> shield measuring 1.5 inches high and fits the 6AL5. I need two (2) of
these.
> Just regular non-heat dissipating shields will be just fine.
>
> I have plenty of 9 pin, 2 inch shields to trade if that's of any interest.
>
> Thanks and 73,
>
> Roger NJ2R
>
>
> Sponsored by the Collins Radio Association
> http://www.collinsra.com
>
>
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