[sdiy] Log/Lin VCAs/Transconductance amps

[Louis van Dompselaar]

When did the LM13700 go out of production?  National still list the  
LM13700 DIP16 as "full production".

And it's available everywhere.  Futurlec even sell it close to the  
National bulk price.


Op 11 mrt 2009, om 12:14 heeft Tom Wiltshire het volgende geschreven:

> There are a number of VCA chips still in current production and  
> available:
>
> SSM2164 quad vca
> SSM2018 single VCA
> THAT2180/2181 single VCA
> THAT2162 dual VCA
>
> All of these seem to be designed primarily for audio level control,  
> and have a dB/mV control response (log). This contrasts with what I  
> think of as the "previous generation" of chips for VCAs:
>
> CA3280
> LM13700/13600
> CA3080
>
> All of these basic transconductance amps have a linear response.  
> Obviously there were a few SSM/CEM VCA chips around too (CEM 3360  
> dual VCA for example) but these are in general even more expensive  
> and harder to get than the short list above.
>
> Does anyone know of a cheap/easily available linear VCA or  
> transconductance amp?
>
> Perhaps I'll have to linearize the SSM2164 and use it as a dual  
> linear VCA instead. This provides an upper limit on cost, since the  
> SSM2164 is about £4-5.