Doepfer

"To fix this, you can either by another module from Doe               
which has three channels of voltage offset/processing, which will 
allow you to offset these AC's into full saweep DC's, positive only 
-or- you can do what I did and make a circuit that does that (it's a 
very simple circuit). My problem is I couldn't afford the rack space 
the Doe. option required, it's a (relatively) huge module designed for 
use with their vocorder."

-or-

Use your mixer and CV source modules as an attenuator/offset. This 
takes up zero additional space. This is what I do with the A156, 
A110, and A111, which are also not bipolar.

Joe