[sdiy] Buffer signal input 2164/2180?

[Neil Johnson]

Hi,

Alexandra Savidis wrote:
> 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?

Depends on what input impedance you want, any HF roll-off or LPF on
the input, if you want to add any input protection, what the optimum
operating point of the VCA is, etc.

For example, the SSM2164 operates pretty optimally with a 30k or 33k
input resistor.  If you wanted a 100k module input resistance then
you'd need a buffer op-amp.

Cheers
Neil
-- 
http://www.njohnson.co.uk