[Collins] Fw: {Collins} Re: KW-1

[k5jv]

Greetings to all,

        A couple of weeks ago there was thread going around about rectifiers 
in the KW-1 transmitter.  I think this thread was left hinging in the air.

        In an apparent effort to save  production costs, some manufacturers 
(E. F. Johnson, and others) wired the rectifier filaments of many of their 
transmitters in series.  Collins was smart enough to parallel the filaments 
of the rectifier tubes in the KW-1.  What this means to us today is that no 
modification is necessary to the original circuit when changing to solid 
state rectifiers, or to 4B32 (CV2518) half-wave xenon rectifier tubes.

        If you want to get rid of the original mercury vapor rectifier 
tubes, but still keep your KW-1 as close to original as possible,  I suggest 
that you use 4B32's.  They are direct replacements for the original mercury 
vapor rectifier tubes.  I have personally used them in the three KW-1's that 
I have owned, and operated, in the past few years.  Of course, there is 
absolutely nothing wrong with going solid state.  I just think that there is 
something very non-aesthetic about opening the doors of a beautifully 
restored (or original) KW-1 and finding two large, black, blobs of solid 
state rectifiers staring you in the face.   Or, worse yet, finding two large 
open sockets when the solid state devices are placed under the chassis.

        We have accepted 3B28's for years in the BC-610, Thunderbolt, 30S-1, 
and many others for years.  In my opinion, the 4B-32 is the rectifier of 
choice for the KW-1.

73 de Lon, K5JV