[sdiy] SSM2164 VCA

[David G. Dixon]

> All the designs I've seen based on the Mike Irwin design change Vref to
> whatever they want the CV range to be. Is there a reason why you
> couldn't just use -15V and scale the resistor connected to Vref to suit?
> Wouldn't the 2164 just be seeing a current input, and not care what
> voltage is on the other end of the resistor?

I think you're right, since the 2164 input is a virtual ground.  I've used a
-5V source through a 100k input resistor.  I could have simply connected the
-15V rail through a 300k resistor (or a -12V rail through a 240k resistor).