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</head><body><p>You want about 100mv pp of signal on the input pin for 1% distortion. If my calcs are right that would be 4.8 Vpp on the input.</p><p><br></p><p>The gain in the output amp seems really high. Vo = I*100000, so to get about 5 Vpp output you need about 25ua into the op amp.</p><p><br></p><p>So I'd guess the noise is from the high gain in the output stage. You'd need that if the input is really low level or the Iabc current is low.</p><p><br></p><p>Like I said this is an off the top of my head guess.</p><p><br></p><p>Jay S.</p><blockquote><p>On August 31, 2017 at 2:09 PM Tim Ressel <timr@circuitabbey.com> wrote:</p><p>Hi,</p><p>I am still having trouble with this VCA design:</p><p><a href="https://drive.google.com/open?id=0B2yaoNYlV1nMWFhSRWUwdlU3TzQ">https://drive.google.com/open?id=0B2yaoNYlV1nMWFhSRWUwdlU3TzQ</a></p><p>It is noisy, and it gets worse as you turn up the gain. I tried<br>switching to a 2164 design but its no longer available in SMT.</p><p>Any ides?</p><p>--<br>--Tim Ressel<br>Circuit Abbey<br>timr@circuitabbey.com</p><p>_______________________________________________<br>Synth-diy mailing list<br>Synth-diy@synth-diy.org<br><a href="http://synth-diy.org/mailman/listinfo/synth-diy">http://synth-diy.org/mailman/listinfo/synth-diy</a></p></blockquote></body></html>