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

[Olivier Gillet]

> The immediate issue that springs to mind is the fact that digital pots work
> in discrete steps rather than being continuously variable.  Just checked the
> spec for the MCP42050 and found it has only 256 steps which would surely be
> audible whether used to control filters or signal amplitude.

It's not specific to this design - synths with digitally generated
envelopes suffer from the same problem. The only difference is that
you can add some low-pass filters in a "digital envelope > DAC > VC
controlled filter/amplifier" path to get less steppy CVs - if you are
not concern about the loss of snappiness.