<div dir="ltr">Yes and I had coincidentally just tried switching those to 100k and it fixes the issue (-5V via 100k to feedback VCA input) and then the +5V connected via 100k to CV summing op amp.<div><br></div><div>Why does this not work with 30k but it is ok with the coolaudio ones?</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Feb 6, 2019 at 2:42 PM Mattias Rickardsson <<a href="mailto:mr@analogue.org">mr@analogue.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto">Hi Danjel,<div dir="auto"><br></div><div dir="auto">with 30k for Rin, do you mean one of the 100k in the linear control circuit?</div><div dir="auto">If so, that's probably the reason it misbehaves.</div><div dir="auto"><br></div><div dir="auto">Best,</div><div dir="auto"><br></div><div dir="auto">/mr</div><div dir="auto"><br></div></div><br><div class="gmail_quote"></div><div class="gmail_quote"><div dir="ltr">Den ons 6 feb. 2019 23:19 skrev Danjel van Tijn <<a href="mailto:danjel@intellijel.com" target="_blank">danjel@intellijel.com</a>>:<br></div></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi there,<div><br></div><div>Has anyone else experienced issues with the SSI2164 used in place of a Coolaudio 2164 in a linearized VCA configuration?</div><div><br></div><div>With no CV applied to the circuit control pin of the VCA should be close to 0 (and it is when I swap back in a coolaudio chip)  but with a SSI2164 the voltage at the control pin is around 0.85V.</div><div><br></div><div>I am using accurate voltage sources for the negative and positive voltage references (-5 and +5). and as aforementioned swapping in a coolaudio chip returns the circuit to working as expected.</div><div>Opamp is a  TI TL072CPWR.</div><div><br></div><div>The only two differences from the datasheet version are that we are using 30K for Rin and 510R+560p for stability;  both are within range of acceptable values according to datasheet.</div><div><br></div><div>Any thoughts?  possibly bad batch of ICs?     </div><div><br></div><div><br></div></div>-- <br><div dir="ltr" class="m_-2009554052604324987m_4586704083112257814gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">cheers,<div><br><div><div>Danjel van Tijn<br>Intellijel Designs Inc.<br>m. +001 <a href="tel:(604)%20773-2426" value="+16047732426" rel="noreferrer" target="_blank">604-773-2426</a><br><br><a href="http://www.intellijel.com" rel="noreferrer" target="_blank">www.intellijel.com</a><br><a href="https://www.instagram.com/intellijel/" rel="noreferrer" target="_blank">https://www.instagram.com/intellijel/</a></div><div><a href="http://www.facebook.com/intellijel" rel="noreferrer" target="_blank">www.facebook.com/intellijel</a><br><a href="http://www.youtube.com/intellijel" rel="noreferrer" target="_blank">www.youtube.com/intellijel</a><br><a href="http://www.twitter.com/intellijel" rel="noreferrer" target="_blank">www.twitter.com/intellijel</a><br><br><br></div></div></div></div></div></blockquote></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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</blockquote></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">cheers,<div><br><div><div>Danjel van Tijn<br>Intellijel Designs Inc.<br>m. +001 <a href="tel:(604)%20773-2426" value="+16047732426" target="_blank">604-773-2426</a><br><br><a href="http://www.intellijel.com" target="_blank">www.intellijel.com</a><br><a href="https://www.instagram.com/intellijel/">https://www.instagram.com/intellijel/</a></div><div><a href="http://www.facebook.com/intellijel" target="_blank">www.facebook.com/intellijel</a><br><a href="http://www.youtube.com/intellijel" target="_blank">www.youtube.com/intellijel</a><br><a href="http://www.twitter.com/intellijel" target="_blank">www.twitter.com/intellijel</a><br><br><br></div></div></div></div></div>