Doepfer

Are there any other modules besides the A-175 that do voltage 
inversion of CV? (A-119, A-116, A-136?). The A-119 doesn't 
seem to handle CV signals very well, seems more suitable for 
inverting audio signals. 
Since I don't have any space left in my rack, is there an easy way 
to construct a little outboard CV inverter? 
Would the polarity switchers cable manufacturers sell work?

Thanks a ton.

M. Dimm