<div dir="auto">Hi Dan,<div dir="auto"><br></div><div dir="auto">Returning to the OP questions about today's OTAs, I'm curious to hear if you specifically need OTAs and some of their properties (linear control, differential inputs, voltage levels, current/voltage interfacing, etc), or if VCAs would also be an alternative?</div><div dir="auto"><br></div><div dir="auto">SSI2164 quad VCA is mentioned often since it's very easy and fun to design with, but if I'd need a linear control I'd probably look for more alternatives before I'd used the linearized 2164 method. It's not the "best" VCA in terms of hi-fi quality, but it's very good - good enough for synths and great price/performance compared to the hi-fi mixing console ones. Also very handy to apply in designs, with a useful dB/V law, and with a huge community knowledge base, which is another variant of "best".</div><div dir="auto"><br></div><div dir="auto">Perhaps you're already skilled in OTA design and prefer continuing using OTAs when it works, which is understandable. :-)</div><div dir="auto"><br></div><div dir="auto">/mr - wouldn't be surprised if a new even better OTA chip saw the light of day soon</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Den tors 8 aug. 2024 20:14Dan Snazelle via Synth-diy <<a href="mailto:synth-diy@synth-diy.org">synth-diy@synth-diy.org</a>> skrev:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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imagine someone asked you to make some new synth modules.</div>
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then imagine that the last time you did so in any quantity above one--- it was 2017. </div>
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I am trying to get a handle on what the parts landscape is like now for cost-effective CV control. Back in 2017 the lm13700 was really the only available OTA . I was just starting to work with the ssm2164 at the time but never used it extensively.</div>
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In the interim I have built synth circuits but only in quantities of one where cost was no object and I was able to rely on my own extensive parts supply. </div>
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So my question is this-- if I am thinking about design for manufacturing<span style="display:inline-block"><span id="m_1286205973923699913hyphen2">—</span></span>what do you think the best option
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Has anyone tried the quad ALFA OTA? Is it even readily available? Same for the new SSM2040. </div>
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OR would you just use the 2164 instead? </div>
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OR would you just try to make discrete OTAS out of say the BCM856DS //BCM847BS</div>
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thanks for any and all opinions on this. </div>
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