[sdiy] the obscure output of a 2164

rsdio at audiobanshee.com rsdio at audiobanshee.com
Sat Mar 11 03:02:20 CET 2017

Is a VCA really equivalent to a voltage-controller resistor in all aspects?

In other words, transconductance is not exactly the same thing as transresistance.

Harry Bissel's Morph-Lag shows the two potentiometers with open connections on one end of each. Is it even possible to run a VCA in an equivalent manner?


On Mar 10, 2017, at 4:58 PM, David G Dixon <dixon at mail.ubc.ca> wrote:
> I tried to use to different 2164 VCAs as variable resistors to control the
> attack and decay independently in a Morphlag circuit, and the two VCAs
> interacted strangely such that I couldn't independently adjust one without
> affecting the other.
> In addition to the two 2164 VCAs having their outputs both feeding a common
> Miller integrator inverting input, their inputs were also treated fairly
> unconventionally, with 1k resistors and diodes pointing in opposite
> directions.  I think it was more the inputs that were the problem than the
> outputs, because I have used 2164s with 30k input resistors and outputs tied
> together in many circuits (including the Rubicon) and this seems to work
> well.

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