Korg Polyphonic Ensemble (was: Re: [sdiy] Secrets of Dan Brown's "The Buchla Code" Revealed

[Grant Richter]

As always, Thank you Jurgen for your generosity.

I could swear I saw a Korg drawing with a very simple oscillator and  
one Buchla LPG like Vactrol per KEY. There were several sections  
shown, then a note to the effect of "remainder of sections as shown".  
I remember thinking the oscillator was very clever because of the low  
parts count.

The resonance was fixed and there were sweep start and extent that  
worked for all sections. The Vactrol LEDs were in groups with a  
series resistor per group and the groups were wired in parallel.

Maybe I dreamed the whole thing, I do that sometimes, draw or read  
schematics in dreams. But they use symbols for components that don't  
exist like capistors and dionts. Not very helpful in the real world.

>
> Grant: the Vactrol-based Traveler is here:
> http://home.debitel.net/user/jhaible/pe1000_2.gif
>
> Caps are selected to match the tolerance of vactrols. (Yes,  
> Hamamatsu.)

The second lowpass section would be Buchla 192 like if they took the  
feedback from the junction of the FET and 10K.

I am not trying to take anything away from Korg or Buchla.  
Engineering is frequently about cross-pollination. Whenever I used to  
get a new engineering project, my first act was to research existing  
practice.

It is not impossible that a Korg engineer looked at a 192 or 292  
schematic.

By the same token, it is just as possible they both had the idea for  
a Vactrol based Sallen-Key completely independently.
>