[sdiy] Simple VCA schematic, anyone?

[Andre Majorel]

On 2007-01-08 20:27 +0100, JH. wrote:

> >Jürgen, you mentioned a single-transistor VCA in the Korg PS-3200.
> >Is it in the signal path ? That machine sounds marvelous.
> 
> http://jhaible.heim.at/polykorg/PS3200_Voice_Cards_orig.gif
> 
> The single-transistor VCA is right after the VCF. (Q401 ... Q412)

Thanks. In the unlikely event someone wanted to build this as a
stand-alone audio VCA, would this be the correct circuit ?

               _
             +  | -
       IN o----||----+--------       -----------o  OUT
               _|    |        \     ^
                     <         \   /
             33 µ    > 330 R   =====   Any small
                     <           |    signal NPN ?
                     |           |
                     = 470 p     |
                     |           |
   VC     o---^v^v---+-----------
 (0~15 V)      1 M

Are the 470 pF cap and 330 ohm resistor part of the VCA ?

Would a BC550 do for the transistor ?

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
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