[sdiy] Digital pots as the gain element in a filter

[Tom Wiltshire]

What kind of filter design is that? I've have guessed 12dB SVF, but it's such a tangle I couldn't work it out. And why does he have 3 Q controls? (I suppose the filter type will tell me that)

And no, I don't know of any other synth designs using digipots for the filter control element.

Thanks,
Tom

On 5 Jul 2011, at 10:31, Olivier Gillet wrote:

> Hi all,
> 
> I always thought this was a whacky idea - especially since it would
> give only an approximate expo response through one of those "linear to
> pseudo-audio" pots trick - but someone ended up doing it!
> http://hackmeopen.com/wp-content/uploads/2011/05/Rockit-Schematic.png
> (From: http://www.kickstarter.com/projects/790206393/rockit-8-bit-synth-kit?ref=live)
> 
> Do you know of other designs using something like this?
> 
> Olivier
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