[sdiy] Potted expo converters

[David Cornutt]

I wonder at what point a microcontroller with A/D and D/A
conversion becomes a more effective solution for this ongoing
problem, at least for new designs.  It seems like it could be
made to work pretty well for control voltages and audio up to
about 4 KHz; the sampling rate wouldn't have to be too
unreasonable to support that well.  The actual conversion
could probably be a lookup table for applications where
precision isn't critical.