Fwd: [AMPS] GRID CURRENT FOR ALPHA 76A

Fri, 20 Feb 1998 19:45:56 EST

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From: KA2YKC@aol.com
Return-path: <KA2YKC@aol.com>
To: steve@1bigred.com
Subject: Re: [AMPS] GRID CURRENT FOR ALPHA 76A
Date: Fri, 20 Feb 1998 19:45:10 EST
Organization: AOL (http://www.aol.com)
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In a message dated 98-02-20 12:54:59 EST, you write:

<< Hello all,

 I have a 'loaner' 76A, three holer to be used over the weekend in the
 contest.  It didn't come with any documentation.

 What does Alpha recommend for grid current for these 3 - 8874 tubes?

 I don't have a clue.

 I've gotten as much as I can out of the amp with a self imposed limit of 25
 mils, about 840 watts.

 73 de Steve, NJ4F >>

I think the manual says 20-25 mils per tube. I just repaired a 76PA for a
friend, and on the SSB HV position, I think the Ip was 1000ma , the grid was
75ma, and I was getting 1400w or so on the internal (relative) meter. Do the
math with efficiency, and it should work out to around 60-70 %..  BTW, I
noticed that by bringing the Load CCW, I could drastically reduce the grid
current with negligible power drop. 

I was impressed with the amp, other than the fact the tubes are hard to come
by and expensive these days !  Be careful of his tubes, it could get to be an
expensive loaner !  Even Sletvana wants over $300 a tube, they should get real
and wake up, I'd spend the extra 30-50 bucks per tube to go Eimac......soapbox
off!

73 Eric
KK2ED

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