[Amps] AL82 3-500 4-400

[Fuqua, William L.]

Two things to watch out for.
The 4-400A tubes are taller than the 3-500Z. Watch out for plate leads getting too close to top shield and the chimneys are too short. You could set the chimneys aside and use small fan to provide some cross air flow to plate terminals.
  Also, the input impedance will be slightly different.
However, conversion should be possible.

73
Bill wa4lav
________________________________
From: Amps <amps-bounces at contesting.com> on behalf of gudguyham via Amps <amps at contesting.com>
Sent: Tuesday, January 26, 2021 3:48 PM
To: Robert W5AJ <woodr90 at gmail.com>; Amps at contesting.com <Amps at contesting.com>
Subject: Re: [Amps] AL82 3-500 4-400

CAUTION: External Sender


4-400 tube will work in an Al82.  No problem.  They will have less gain and less output but you’ll get power.  You’ll do better if you use less bias.  Use it in SSB mode to up the idle current.  There “may” be an input matching issue but it shouldn’t be really bad.


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On Tuesday, January 26, 2021, 3:35 PM, Robert W5AJ <woodr90 at gmail.com> wrote:



Have Ameritron AL82 amp, No Tubes

Have extra Eimac 4-400 tubes



Looked at some amp's schematics for 4-400 and appears these would work in
AL82

Have fired up filaments in AL82 (no HV)



Any one tried this or have go/no go thoughts?



73 W5AJ







Robert

Midland, Texas

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