[sdiy] SEM filter questions

[David G Dixon]

Hey Team,

A buddy has asked me to build an Oberheim SEM-inspired filter.  I've been
looking at a schematic I found on the web for something called "SEM-1A"
which looks to me like a garden-variety SVF built around CA3080 OTAs and
caps with 2N4302 JFET buffers.

Is this "the" SEM filter?  I was under the impression that it was based on a
CEM chip.

Also, is there something special about this particular SVF which makes it
sound unique?  I notice that the resonance circuit has a kind of interesting
looking resistor network and a couple of anti-parallel diodes.  Do the JFET
buffers impart any special qualities to the filter?

Any insight would be most appreciated!