[sdiy] digitally controlled potentiometers

[chopin_o]

>I have been working recently on digitally controlled potentiometers.
>The idea is to be able to use these potentiometers as drop-in replacements
>for cloning projects and new synth projects.

I for the similar purpose use multiplying DAC, for example old AD7520,
Vin (bipolar) ---> VREFinput.  
Vout=Vin*(DataDAC). 
Especially convenient serial DAC's.
Igor.