[sdiy] OTA performance (was SSM chip reissue)

[Andre Majorel]

On 2017-04-24 23:22 +0100, Neil Johnson wrote:
> Tom Wiltshire wrote:
>
> > What, too embarrassed to say that the matching is a bit
> > worse than a quarter decibel out at -40dB?!
> > What's the smallest decibel difference people can detect?
> > About 3dB, isn't it? Quite a bit more than 0.25dB.
> 
> Gain matching is important in stereo recording otherwise the stereo
> image drifts away from where you want it.

Right. Gain matching between channels is why serious mic preamps
have stepped gain controls instead of pots which would be much
cheaper.

How relevant gain matching within the same chip is to synth
circuits is one of the many things I have no clue about. :-)

A patch using FM in a polyphonic synth can be completely ruined
by mismatched VCA gains across voices. Before you dismiss it as
a simple matter of having the CPU calibrate the VCAs, try it.
Because I've seen it done in the Alesis Andromeda and it was not
enough, not by a long stretch.

-- 
André Majorel http://www.teaser.fr/~amajorel/