<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">I used Self’s series/shunt config as the basis for the mutes in the Poltergeist mixer and they work pretty well.</div><div class=""><br class=""></div><div class="">If you go this route, watch out for a 47kR in the feedback loop of the opamp that should read as 4k7R.</div><div class=""><br class=""></div><div class="">epk</div><div class=""><br class=""></div><div><blockquote type="cite" class=""><div class="">On May 26, 2018, at 11:16 AM, Mattias Rickardsson <<a href="mailto:mr@analogue.org" class="">mr@analogue.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="">Muting with the <span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class="">series/shunt FET solution as described by Douglas Self is probably superior to the simpler Boss pedal solution when there is need to shut off the entire audio range, so be sure to check it out. I was dabbling with it yesterday, trying out alternative JFETs as the BSR57 is suddenly out of stock globally.</span></div><div class=""><br class=""></div>Switching at zero crossings still gives a discontinuous derivative, so it's like having the clicks 1-pole low-pass filtered - not removed. Often they will still be heard, especially for purely low- or mid-frequent material without many overtones, so it had better be tested in a particular application before trusted as a click-free solution.<div class=""><br class=""></div><div class="">That said... how is it done in existing "clickless" switch ICs? I guess it's just switching at zero crossings, or are they fading the signal in some way?</div><div class=""><br class=""></div><div class="">It's still probably seen as "good enough" in some high-end designs, for instance Zähl writes:<br class="">"click-free audio switching using zero cross detection on parameters relevant when mixing live"<br class=""><span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class=""><a href="http://www.zaehl-am1.com/" class="">www.zaehl-am1.com</a></span><br class=""></div><div class=""><span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class=""><br class=""></span></div><div class=""><span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class="">A short fade-in/out is often mentioned as the better solution, but the long fade times needed for bass tones are unnecessarily long for high frequencies. Also, depending on the product or use case, a fade can be a very problematic solution if, say, a channel is supposed to be switched on for just a particular time slot for a drum sound or similar sudden events. If you don't switch it on "too early", you'll miss the attack of the sound. If you switch it on early enough, you also get some of the unwanted sound preceding the wanted sound. And the same problem applies to the end of the time slot. Btw, the same problems arise when using multiplexed & filtered CVs to feed VCAs - they don't shut on/off instantly. In a drum machine or multi-timbral synth or automated mixing in general this can be a real pain in the bass.</span></div><div class=""><span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class=""><br class=""></span></div><div class=""><span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class="">/mr</span></div><div class=""><span style="color:rgb(34,34,34);font-family:Roboto,system-ui,-apple-system,system-ui,".SFNSText-Regular",Oxygen-Sans,Ubuntu,"Helvetica Neue",Helvetica,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class=""><br class=""></span></div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On 26 May 2018 at 10:27, Andre Majorel <span dir="ltr" class=""><<a href="mailto:aym-htnys@teaser.fr" target="_blank" class="">aym-htnys@teaser.fr</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 2018-05-24 20:47 +0200, Roman wrote:<br class="">
<br class="">
> How about detecting zero-zrossing and shutting down the audio<br class="">
> with clamping MOSFET or whatever when signal is no more than<br class="">
> 1mV away from GND? No clicking.<br class="">
<br class="">
</span>If you want to hear what switching at zero-crossings sounds<br class="">
like, play the WAV file at<br class="">
<br class="">
<a href="http://www.teaser.fr/~amajorel/gatedsine/" rel="noreferrer" target="_blank" class="">http://www.teaser.fr/~<wbr class="">amajorel/gatedsine/</a><br class="">
<br class="">
The signal being switched is a low-frequency sine so as not to<br class="">
mask the artefact. On a signal with more high frequency content,<br class="">
the artefact would be less conspicuous.<br class="">
<span class="HOEnZb"><font color="#888888" class=""><br class="">
-- <br class="">
André Majorel <a href="http://www.teaser.fr/~amajorel/" rel="noreferrer" target="_blank" class="">http://www.teaser.fr/~<wbr class="">amajorel/</a><br class="">
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