I don’t believe the Doepfer SEM is capable of self oscillation if that is important to you. It’s a very classic sound. Very late-70s/early-80s vibe. Definitely on my shortlist.
-- farkas

Possibly related to this post, I just found out this weekend that the Doepfer Extreme Filter A-106-1 indeed is capable of self oscilation, and to my surprise to an audible and absolutely usable level. Im not sure I remember the patch correctly, but it definitely involved no audio oj the inputs (obviously) and the use of the send/return jacks (I think I just amplified the module's natural send output and routed back without creating an obvious loop.
Im sorry I dont remember and this is my first post in this forum, so if anyone ever finds this useful and/or you want to know the exact patch, let me know..