Have you considered using a switchable PS that runs FWB and FWD? One switch
or vacuum relay and you have 2 voltages. Consider 3500VDC for Class C (not
too deep on the bias tho) CW and 1750V for a real clean SSB.
Carl
KM1H
----- Original Message -----
From: "Vic K2VCO" <k2vco.vic@gmail.com>
To: "Amps reflector" <amps@contesting.com>
Sent: Wednesday, August 08, 2012 11:06 PM
Subject: [Amps] 4CX1500B project
> 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/
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1424 / Virus Database: 2437/5189 - Release Date: 08/09/12
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|