[sdiy] Precision voltage offset

[media at mail1.nai.net]

>Instead of a voltage divider and selector switch to the summing input, you
>could have a single appropriately sized resistor and trimmer connected to
>your reference voltage. They key is having a close match (or trimming) your
>R-in and R-feedback so you don't compromise the accuracy of your keyboard
>CV.  The only thing I would change here is having a fixed reference as
>opposed to using the power supply rails like I did (me bad).

Really??  I would think the rails would be rather stable.  Is the
fluctuation audible??

>So, one LT1013, and handful of resistors and one trimmer and you are set.
>There is a lengthy and detailed document explaining how the circuit works
>that will help you select just what you need.
>http://www.wiseguysynth.com/larry/jlh-822/822_theory.htm

That could have saved me some typing!!