[sdiy] Quick query about 2164 VCAs

Neil Johnson neil.johnson71 at gmail.com
Sun Mar 17 23:58:58 CET 2019

Hi Tom,

> What makes you think that:
> A) this parallel-inputs-independent-outputs arrangement only works if the CVs are identical?

Looking at the schematic shown in the SSI2164 datasheet and
considering the various current paths within it I have a strong
suspicion that unless the currents in the VCA bit are balanced between
the gain cells then any imbalances due to different control voltages
will cause the inputs stages to behave differently, and so the input
current will not be shared equally between the gain cells.

> B) the outputs have to be paralleled too?

That's a less certain hunch, and I may be wrong, or right ;)  The only
real way to test this would be to build it and try it out.

What I do know is that paralleled ins and outs does work, as I have
that working on the bench.


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