[sdiy] Simple VCA schematic, anyone?

[Martin Gustafsson]

I simulated that circuit:
http://213.67.25.74/bild/test/cir.JPG
http://213.67.25.74/bild/test/output.JPG

Seems to work nice...
Simulation is one thing.. works in real-world.. a completely different 
thing.




/Martin



Andre Majorel wrote:

>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 ?
>
>  
>