[Central-Electronics] Drive a Johnson KW

[Colin Lamb]

I am assuming you are talking about the desk KW.  The rf drive is no problem for the CE.  However, the desk has a built in modulator but no audio driver, so you will need high level audio (probably at 500 ohms if I remember) to drive the modulators.  This may be on the order of 10 watts or so.  One of the rigs often used is the Johnson Ranger and that provides audio output from the modulators to drive the desk modulator.  Johnson also sold an accessory to use with the desk for those people who were going to drive the desk with a different rig, or a cw only rig.  That was simply a separate audio driver system.  The problem with the CE is that it uses low level audio and modulation into the linear finals, so there is no high level audio output.  

You could take low level audio output from the CE and use it to drive a pair of 6L6 drivers into a 500 ohm output (this is from memory and I did not look at the schematic).  You may want to get the old Johnson catalog out and read about the driver that was available for it.  You can probably find a schematic, too.  

73,  Colin  K7FM