[Amps] Series C in amp output

[Carl]

Often tubes can be very long lived as has been reported many times.

A few years ago I had a well used Tempo 2000 (Johnson Thunderbolt II) in for 
service that still had its original 1962 3-400Z's at full power.

My LK-500ZC was partial payment from Amp Supply for some consulting work; 
the 1986 3-500Z's are still at full power even after having been beat real 
hard during decades of contesting, serious DX chasng and as AM linear  a 
good part of the past 10 years. The glass is a bit  brown but the tubes were 
always run in spec.

My 1963 prototype NCL-2000 was converted to 6M in 64 and the defective 8122 
RCA  tubes (no screen support) were replaced in 67. Those were removed in 
2011 only because the output was down to 600W and the IMD was way up. Never 
abused. The pulls from a distributed amp are an easy 1200W.

I have a DTR-2000L, MLA-2500, and SB-230 with the original tubes since I 
dont beat the hell out of them.

Carl
KM1H


----- Original Message ----- 
From: "Mark, K5AM" <k5am at zianet.com>


>
> 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
> years.
>
> 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. www.zianet.com/k5am/amphfkw.html
>
> 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: www.zianet.com/k5am/amp6mkw.html
>
> 73,
>
> Mark, K5AM www.zianet.com/k5am


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