I've been thinking about my next project for some time, and I can't seem to
shake the idea
of an 160-10M amplifier using the 4CX1500B. The tubes and the beautiful SK-800B
socket are
just burning a hole in my workbench, as it were.
So I am thinking of running it in AB1 according to the parameters in the
4CX1000 datasheet
-- 3kV on the plate, 325V on the screen and -60V bias. This will give me full
legal output
from one tube. It is possible to reduce the bias and screen voltage and run it
closer to
class A for much better IMD, but as a CW operator I'd prefer a few more watts
(actually, a
CW/SSB switch is a possibility).
I am considering a grid-driven circuit with a 50 ohm swamping resistor. It
seems to me
that it would require 60v peak to just overcome the bias, which comes out to 72
watts
drive for AB1 operation. Is this a reasonable assumption?
This configuration would make it unnecessary to build and fiddle with a tuned
input
circuit. I'm also thinking about using the G3SEK tetrode board, which would
solve a lot of
little problems in one package.
Does anyone have comments or suggestions?
--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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