To: <amps@contesting.com>
> Date: Sat, 23 May 1998 19:23:32 -0700 (MST)
> From: richl@aztec.asu.edu (RICHARD LANGEVIN)
Hi Rich,
> I'm new to the list but have read the archives and want to build
> an amp. The guys at the club said that I should try a 4-1000 tube
> because they are "very forgiving".
The tube might forgive you, but you might not forgive it! 4-1000A's
are notoriously unstable at high anode voltages, and getting a
bit scarce.
You will need about 5-6 kV and a good bit of drive to get 1500 watts
out in grounded grid. The driving impedance is high, and that makes
the gain low.
If you do run high anode voltages in an attempt to get
enough gain, you will probably run into troubles.
I'd suggest you consider something with a MRI pullout tube Rich, like
an 8877 or a pair of 3CX800's. They operate at lower voltages, have
better IMD performance, are much more stable, and are more commonly
available.
Everything will be a lot easier, and you'll get a lot more power
gain.
If you do want to build a 4-1000, maybe someone can suggest a good
article. I've tossed all my old magazines out.
73, Tom W8JI
w8ji.tom@MCIONE.com
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