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

[Grant Richter]

Hi Jurgen,

Hey, I could be completely full of it.

I recall seeing a center tapped Vactrol in a Sallen-Key setup with  
like 4700 pF and 1000 pF values used in some Korg design? There was  
no 220 to ground.

The Vactrol was a Hamamatsu and not a Perkin-Elmer.

Yes, they added gain to the feedback amp. Why Buchla never did is a  
real mystery?

Do you have these published any place? I sorta think I saw them on  
your site at some time in the last 10 years.

Korg is my favorite MI company. They have made so many good keyboards.


On May 19, 2006, at 7:28 PM, JH. wrote:

>>> Also part of the filter for the Korg Polyphonic Ensemble keyboard  
>>> was
>>> lifted whole heartedly from the Buchla design (pretty sure the Korg
>>> drawings have latter dates).
>
> Which part?
>
> The traveler is just a S&K VCF (no VCA switching as Buchla), with  
> added
> variable resonance (unlike Buchla).
>
> And the individual voices, yes that's LPF and VCA combined, but look
> at this clever implementation, with simple BJT instead of expensive
> Vactrols !!
>
> JH.