[sdiy] CV offset question.

[Paul Schreiber]

Use 2 regulators a 7805 and a 7905 to reduce the 'swing' by a factor of 3. Then, 
use a LT1013CN8 from www.digikey.com. This is a special op amp that is 
*specifically made* for very accurate scaling/summing of DC voltages. OK, it's 
$4, what's your point? :)

Lastly, you can't 'add in' the voltage off the pot wiper directly, you need to 
use an op amp summer that lets you use the ratio of 2 resistors to then take the 
+-3V swing to whatever you need.

Paul S.