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

[Benjamin Tremblay]

Yup this totally makes sense. A generic replacement would probably not please anyone. 

> On Oct 5, 2020, at 12:39 PM, Ben Stuyts <ben at stuyts.nl> wrote:
> 
> Hi Pete,
> 
> The PDF came through fine. The list allows messages up to 1 MB.
> 
> Ben
> 
> 
>> On 5 Oct 2020, at 18:23, Pete Hartman <pete.hartman at gmail.com <mailto:pete.hartman at gmail.com>> wrote:
>> 
>> 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 <mailto: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 <http://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> <http://www.synthcube.com/cart <http://www.synthcube.com/cart>>
>> > 
>> > 
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