[sdiy] Buffer signal input 2164/2180?

[David G. Dixon]

> There is any need or benefit to buffer the input signal 
> (using an op-amp), when using a SSM2164 or THAT2180 for a 
> modular synthesizer's VCA?

Not unless the source is unable to drive the 30k input resistor.  I
generally put a 100k attenuator pot on the input, so this is not an issue.

There is a benefit to buffering the control signal, however, as the input
impedance of 2164's VC pin is only 5k.