[Premium-Rx] Stereo

[Terry O']

I was given a butchered WJ receiver that contained a stereo 
demultiplexer.  I have never revived this radio to see if it works.  The 
idea is great, but in this radio, the mods done to the original IF and 
audio stages are appalling.

During the CEI years, Ralph Grimm designed a stereo tuner and amplifier 
pair that was manufactured in the 6006 Executive Blvd plant.  I have 
pictures of dozens of these units under construction and testing.  They 
were never sold.  They were given away by Grimm.

He also made the schematics available to employees and I have spoken to 
a couple who used them to build copies of these units for themselves.

This equipment and documents are extremely rare.  I hope to see examples 
of them some day.  It would be interesting to see if Grimm used in house 
and readily available 21.4 MHz IFs or designed his own 10.7 MHz 
circuitry.  He was so much of a perfectionist that I am relatively 
certain these units are not populated with circuitry made anywhere else.

Terry O'
http://Watkins-Johnson.terryo.org
http://BlackRadios.terryo.org


On 12/10/2016 7:21 PM, Peter Ratuschni wrote:
> Hello Peter,
> nice idea! I used to take the LF signal from the video out of a wj 
> 8730A to feed the mpx circuit of a slightly modified FM tuner. (The 
> 8730's audio output is to much lowpass filtered to contain any stereo 
> information.)
> best regards
> Peter
>