[sdiy] Unused SSM2164 cell

Mattias Rickardsson mr at analogue.org
Mon Jul 20 14:07:55 CEST 2015

On 20 July 2015 at 13:52, Olivier Gillet <ol.gillet at gmail.com> wrote:
> What I'm wondering is if the oscillations the compensation network is
> supposed to suppress happen spontaneously,

Probably yes, oscillations that can occur in normal use with nominal
signal input impedance around 30k. I wouldn't expect oscillations to
have the chance occur if the input is connected stiffly to ground.

> or only in response to HF
> components (eg sharp edges) in the incoming audio signal (in which
> case they could not occur is the input is just connected to ground
> through a resistor).

Then I guess they wouldn't be "oscillations". :-)

>>>The board is already crammed so I can't follow my own advice
>>>which would have been to try to sneak in an "easter egg" VCA
>>>accessible through extra pads on the back of the module.
>>>So what would be the best way to connect an unused SSM2164 cell?

I'd try to cram in ONE more resistor, and put the last VCA in parallel
with one of the other three, controlled by the same CV, effectively
halving (or so) the signal noise of these tandem VCAs. :-)


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