[HAM] Hammond S6 plus PR40

[HOlsen5629 at aol.com]

<< Looking for info on how to connect a S6 to a PR40. The two 200 ohm 
resistor technique in the archives doesn't work. Any ideas? Thanks  John >>

Unless you have lots of signal voltage available at the speaker output of the 
chord organ, using resistors as a voltage divider won't work very well.  You 
actually need *twice* the signal voltage required to drive the Hammond tone 
cabinet to full output.  An interstage or line transformer with a 1-to-2 step-up 
is much more efficient, and is ideal for this application.  Input and output 
impedance are not critical, but you do need a transformer with a center-tapped 
secondary.  

Ham/Suz currently uses a small signal transformer in the input of 122XB 
Leslies that adapts the single ended 11-pin system to the original 122-type 6550 
circuit.  This same transformer is also perfect for making old Hammond tone 
cabinets work with organs that only have speaker outputs.  

Here's the hookup: The transformer's primary is connected to the organ's 
speaker output.  The secondary is connected to pins 1 and 6 of the tone cabinet 
input.  The center-tap is grounded and also connected to pin 2.  Pin 5 is not 
used, but you must supply mains AC to pins 3 and 4 to power the TC.  That's it!  
Quick, easy, and hardly rocket science.

Harvey Olsen
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