Why not just replace the pots with rotary encoders and get rid of all the
analog stuff?

-----Original Message-----

        I am doing similar analog multiplexing of pots.  In my case, it's 24
10K
pots going thru 3 CD4051s into 3 analog inputs on a 16c74a.  The pots
have +5V at one end and ground at the other.  The wiper goes directly to
the appropriate 4051.  No capacitors on any of the signal leads, though
there are, of course, bypass capacitors on the 4501s and the PIC.  I get
stable 8 bit value.  Set the pot and the number stays.
        As I recall, I'm allowing something like 20uS for the multiplexors
and
the A/D to settle before starting the conversion.  The 16c74a is running
at 16 MHz.
        I think the key to getting stable A/D readings is having stable
samples.
 This is largely accomplished by the use of ground planes so everyone
agrees on where ground is.

Harold