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Re: [Amps] Series C in amp output

To: Bill Turner <>, Amps group <>
Subject: Re: [Amps] Series C in amp output
From: "Mark, K5AM" <>
Date: Thu, 15 Feb 2018 21:23:37 +0000
List-post: <>

Bill, the amplifier was built in 1971, and ran with the
first tube for 17 years. That tube still ran perfectly,
but I had a few spares on the shelf, and read
somewhere that it was good to rotate them, for
gettering. So I began to rotate tubes about every five

Very heavy DXing and contest use over 47 years, but
no problems. The 4CX1000A has serious grid and
screen current limitations, but the amp has a full set
of protection circuits.

As for tube life in general, I can relate that the 6
meter amplifier that I built in 1961, with push-pull
Eimac 4-400A tubes, is still running full power after
57 years, with the original tubes, used to work 138
countries on 6 meters. Was Eimac great, or what?
And of course Bill Orr, W6SAI (SK), the Eimac ham
contact at the factory, was great to chat with
whenever I phoned him with a question.

6 meter amp:


Mark, K5AM

On 2018-02-15 04:50, Bill Turner wrote:
------------ ORIGINAL MESSAGE ------------(may be snipped)

On Wed, 14 Feb 2018 18:15:04 +0000, K5AM wrote:

Working fine for 47 years.


Same tube?

73, Bill W6WRT
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