Basically the effect is that when I touch a pot connected on ADC2, say, ADC4 changes value. (ADC1 and 3 are unconnected).
However I haven't grounded the unused ADC inputs (they're floating which apparently isn't recommended?) so that could well be the issue, but the issue seems to go away if I press the ADC IC. So maybe I should just resolder that part.
Anyway, no big deal for now because I need to make a much bigger 16 pot input board this weekend to connect to the ADCs. Will see what happens when they're all in use.
Thanks for your help!
M