[Amps] Life of tubes in ham service
invertech at frontierisp.net.au
Tue Dec 26 17:27:08 EST 2017
Rob, I concur with your succinct sentiments here about transmitting tubes.
The only proviso I would make is the inclusion of a soft-start mechanism on
the filaments to bring them up slowly in a controlled manner at initial
switch-on; and ensure the filament voltage as measured at the socket pins is
tightly within manufacturer's specification.
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Rob Atkinson
Sent: Wednesday, 27 December 2017 3:45 AM
To: amps at contesting.com
Subject: Re: [Amps] NXP 65V LDMOS 1K80H-1800W
"What happens when they quit making tubes?"
For some tube types that happened decades ago. But you can still find
plenty of good 810s etc. decades later.
In other words, what happens when no tube of any type is made?
Answer: Not much, except prices may go up.
What happens when tubes no longer exist?
Not our problem because we'll all be SK.
Why are you so flippant?
Because millions of tubes have been made and for ham use, a pair of
3-500Zs (to use them as an example), will outlast all of us _if they
are treated properly_.
That's the rub. Broadcasters wear out tubes because they run them day
and night non-stop for a year or two and they lose emission.
Hams don't do that. The only time a tube wears out in a ham rig is
when hambone abuses it, usually by running too much plate current or
Most common is the single 3-500 "Kilowatt amp" that pisses away 3-500s
every 3 years or so. A certain manufacturer should get a medal from
the Chinese company making 3-500s these days.
If you know how to run your tubes, they'll be running after you are in
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