<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">The very low cost of a 2164 clone these days is a motivating factor. Not sure how to keep the cost low with a voltage-to-current converter added on. Since the classic 2164 VCA is 2/4 2164 mated into a linear circuit, maybe a small mod would make this viable?<div><br></div><div>My 0.2 cents.<br><br><div dir="ltr">Benjamin Tremblay</div><div dir="ltr"><br><blockquote type="cite">On Oct 2, 2020, at 11:16 AM, info synthcube.com <info@synthcube.com> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Greetings all<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">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.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">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. </span><span style="font-family:"Calibri",sans-serif">Is anyone perhaps interested in a small commission to design, prototype and test something?</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">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?”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">We then asked a good friend with superb technical chops and his thoughts are below….
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><i><span style="font-family:"Calibri",sans-serif">“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”
<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></i></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Papyrus;color:windowtext">Thanks-<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Papyrus;color:windowtext">Chris
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:Papyrus;color:windowtext">synthCube<o:p></o:p></span></p>
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