[R-390] 6DC6 Replacement

[Steve Goode]

Alright!  I must confess that I have had similar evil thoughts.

WARNING---SAND STATE THOUGHTS TO FOLLOW!!!!

I love the way my R-390A performs.  Right now the only sand in it is the
Navy approved power supply changes.  It even has a working ballast tube.
But I want this receiver to work forever!  So what happens when I run out of
tubes?  My thoughts are that anything behind the mechanical filters is fair
game since that should have minimal performance hits in dynamic range,
sensitivity, etc.  So I was thinking of looking at the IF, detector, agc,
calibrator circuits to start experimenting on.  What I have found so far in
discussions with others who have actually done solid state conversions is an
article from the April 1977 QST (it is not the April fool article).  This
article shows how to make plug in solid state replacements for any tube
using JET or MOSFETs in cascode with high voltage transistors.  This is as
far as I have gotten.  Anyone else willing to confess?  Anyone actually
succeeding in doing a solid state conversion?

Steve, K9NG