Grumpy_Mike:
Yes I would expect it to do.
By reading a pot you are adding a lot of overhead to the code and altering the overall sample rate that is achievable.
I understand that - but even without reading the pot I was getting well over 100k / sec. I would expect even with reading the pot every cycle it would only delay it by a couple microseconds - even if I lost 20us per cycle I would still be getting 40k / sec or so - which is a totally acceptable (essentially noise-less) sample rate.
And, in terms of symptoms, I'm still getting noise when the pot is left untouched at an intermediate value (i.e. not the min or max value). But the noise goes away (even when still reading the pot) at the max and min settings of the pot.
That would totally make sense to me as causation if not for the fact that the noise goes away at the max and min settings.