[sdiy] Sequencer tuning update. Good & bad news.

[harrybissell]

OK lets say... you have ONE LM329... driving an
opamp buffer. This suppies voltage to the top of each switch.

The wipers of each switch go to the 4051 (with say 200 ohms
on resistance when selected... 10^12 off).  The output of the 4051
goes to the non-inverting input of a TL072 opamp (so with THAT
high of an input impedance... the extra 200 ohms doesn't do a damn
thing).

If all the resistors in ONE switch are matched to each other... the next
switch just needs to be CLOSE in resistance... they could be all 100
ohms
or 110 ohms, or all 90 ohms...  With the high impedance of the buffer
they
could be 10K ohms...  (but usually you want some 'real' current going
through
a switch contact)

I suspecting that the tuning error you have is some small, but very real
loading on the circuit.  Probably mr Ohm would tell you why its
happening...
There is some non-accounted for load, somewhere...

Isn't design fun ??? :^P

H^) harry