Doepfer

> Hello, is the A-131 DC or AC coupled?

The A-131- is DC coupled (unless you have the old version with CEM3381,
these were AC coupled).

> Is it possible to modify A-131 to have one CV input be Exp. and the other
be Linear?

No the current source is different for linear and exponential versions. If
you own the old version another circuit (CEM3382 instead of CEM3381) woul
have to be installed.

Best wishes
Dieter Doepfer