[AMRadio] sockets for 4cx250b/4x150

Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Sat Dec 2 18:49:12 EST 2006

I worked W3MPG today, who was using a single
4CX150f (26 volt fil) in screen modulated service.
It sounded very good, and the entire modulator
was a Berringer mic preamp gizmo.
Marty said he was getting 40 watts carrier out at about 800
volts, and you could run the tube up to 2000 volts and
likely get what, 100 watts out?
The 4CX250 series has 250 watts of plate dis, what would that
be good for using screen modulation?

A pair at 2000 volts might give a nice amount of power out,
and very good audio, with no modulator or mod iron.

Using variacs on the bias and screen volts, I suppose
you could plate modulate it as well, if you modulate the screen
as well as the plate.

It seems like a pair could make a small 200/300 watt rig with
good audio.

I have a crap load of tubes, but only one socket and two

Fair radio used to sell them, where do you get them now?


More information about the AMRadio mailing list

This page last updated 14 Dec 2017.