[sdiy] SEM filter questions

[Mattias Rickardsson]

On 19 April 2012 07:22, David G Dixon <dixon at mail.ubc.ca> wrote:
>
> http://www.synthfool.com/docs/Oberheim/sem2sch.pdf
>
> Is this "the" SEM filter?

Yep! That's the schematic of the whole SEM synth.

> I was under the impression that it was based on a CEM chip.

Nope. :-)

> 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?

Good questions! I'd like to hear the opinions as well.

/mr