[sdiy] SSM2020- work-alike SMT to thru-hole conversion pcb?

[Pete Hartman]

Not sure the list accepts attached PDFs....

This is the doc for the filter in question, the schematic is the last page.

Definitely not looking for a "general purpose" sub so much as a way to
replace the unobtanium chip and retain the same function and character.

Pete




On Mon, Oct 5, 2020 at 4:57 AM Roman Sowa <modular at go2.pl> wrote:

> SSM2020 can be used in so many different ways and probably in your
> application it's only used in one of them. I mean it would be silly to
> recreate all possible signal and control inputs of SSM202 with other
> chips if in destination circuit it's wired to work in one specific way.
> So depending on what it does in this particular circuit, it may be
> easily replaced by either SSI2164, or AS3330, or AS 3360 or AS3363, or
> AS3364 or who know what else if not LM13700.
>
> I mean, making 1-to-1 clone of SSM2020 to fit in one specific circuit is
> like recreating working replica Yamaha GX-1 and use it only as a plant
> stand.
>
> If you show schematics of the device then possibly there will be 20
> people offering help in replacement design.
>
> Roman
>
> W dniu 2020-10-02 o 17:08, info synthcube.com pisze:
> > Greetings all
> >
> > A few years back we made 15V conversion PCBs for some of Analog
> > Metropolis 12V eurorack filter PCBs to use with Frac and 5U panels. The
> > AM2140 uses the SSM2020 VCA chip which of course is unobtainable, and
> > does not appear to be in the pipeline for Sound Semiconductor or Alfa
> > Rpar to re-make.
> >
> > We’d like to hear from you about what it would take to create an adapter
> > PCB to convert certain SMT components to a SSM2020 ‘work-alike’
> > compatible with the thru-hole DIP spacing. Is anyone perhaps interested
> > in a small commission to design, prototype and test something?
> >
> > We asked Dan Parks from Sound Semiconductor , and his initial thought
> > was (paraphrased)  ‘someone might be able to create a SSM2020 work-alike
> > using the SSM2164 or?”
> >
> > We then asked a good friend with superb technical chops and his thoughts
> > are below….
> >
> > /“The input to the SSM2020 is a differential voltage. The input to the
> > SSM2164 is a current. It is not clear to me what ranges would be
> > equivalent for the voltages vs the currents either, most OTAs want very
> > small inputs to avoid distortion. Honestly it might be easier to
> > duplicate it with an LM13700 and some transistor pairs; while some care
> > would have to be put into finding equivalents there too, it's a closer
> > architecture. The SSM2020 is using the transistor mirror at the bottom
> > for control, that goes from linear input to exponential current for the
> > control, just like in a VCO's expo converter” /
> >
> > //
> >
> > Thanks-
> >
> > Chris
> >
> > synthCube
> >
> > 44 north road #50, second floor
> >
> > bedford, ma 01730  usa
> >
> > +1 781-538-6519 main
> >
> > +1 781-538-6521 fax
> >
> > +1 248-890-1905 mobile
> >
> > www.synthcube.com/cart <http://www.synthcube.com/cart>
> >
> >
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