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<p>The legendary website of Rod Eliott (ESP) provides a good
overview as well:<br>
<a href="https://sound-au.com/articles/muting.html"
class="moz-txt-link-freetext">https://sound-au.com/articles/muting.html</a></p>
<p><br>
</p>
<div class="moz-cite-prefix">On 2025-05-08 15:12, Mike Bryant wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CWLP265MB713254F3DBA05199BB9D438BDB8BA@CWLP265MB7132.GBRP265.PROD.OUTLOOK.COM">
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Chapter 21 (well it was in edition 2) of Douglas Self's book on
audio which should be on every audio engineer's shelf covers
almost every way of muting a signal. One of those should suit
you.</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif"
style="font-size:11pt" color="#000000"><b>From:</b> Synth-diy
<a class="moz-txt-link-rfc2396E" href="mailto:synth-diy-bounces@synth-diy.org"><synth-diy-bounces@synth-diy.org></a> on behalf of Benjamin
Tremblay via Synth-diy <a class="moz-txt-link-rfc2396E" href="mailto:synth-diy@synth-diy.org"><synth-diy@synth-diy.org></a><br>
<b>Sent:</b> 08 May 2025 13:56<br>
<b>To:</b> synth-diy mailing list
<a class="moz-txt-link-rfc2396E" href="mailto:synth-diy@synth-diy.org"><synth-diy@synth-diy.org></a><br>
<b>Subject:</b> Re: [sdiy] Muting circuits for line out</font>
<div> </div>
</div>
<div>
<div dir="auto">The original design had the power switch on the
volume knob. I suppose that was a way to mitigate this.<br
id="x_x_lineBreakAtBeginningOfSignature">
<div dir="ltr">Benjamin Tremblay</div>
<div dir="ltr"><br>
<blockquote type="cite">On May 8, 2025, at 8:44 AM, Benjamin
Tremblay <a class="moz-txt-link-rfc2396E" href="mailto:btremblay@me.com"><btremblay@me.com></a> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">Oh wait, I suppose the patent is for an fm
signal that has not yet been demodulated.<br
id="x_x_lineBreakAtBeginningOfSignature">
<div dir="ltr">Benjamin Tremblay</div>
<div dir="ltr"><br>
<blockquote type="cite">On May 8, 2025, at 8:30 AM,
Benjamin Tremblay <a class="moz-txt-link-rfc2396E" href="mailto:btremblay@me.com"><btremblay@me.com></a> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Hello,</div>
<div>I have this lovely Univox JR-5 rhythm machine I
have modded with knobs to control the sound mix. The
original circuit was high gain but impedance
sensitive so it summed current, not voltage and was
very </div>
<div>I added a simple op amp to handle the mix. When
power is turned on there is a horrible thump that
sounds like it is 100x too loud. </div>
<div>I have been looking for a simple muting circuit.
When I was repairing a Roland MC-909 I saw the
muting circuit was little more than a pair of BJTs
shorting the signal path. </div>
<div>I also saw this novel patent which attenuates the
signal without much voltage offset, maybe?</div>
<div>
<div class="" style="display:block">
<div class="x_x_apple-rich-link" role="link"
style="display:inline-block"><a
class="x_x_lp-rich-link" rel="nofollow"
href="https://patents.google.com/patent/US4288753A/en" dir="ltr"
role="button" width="300"
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<a rel="nofollow"
href="https://patents.google.com/patent/US4288753A/en"
style="text-decoration:none" moz-do-not-send="true"><font
color="#000000"
style="color:rgba(0,0,0,1)">US4288753A - Muting circuit with operational
amplifier - Google
Patents</font></a></div>
<div
class="x_x_lp-rich-link-captionBar-textStack-bottomCaption-leading"
style="word-wrap:break-word; font-weight:400; font-size:11px; overflow:hidden; text-overflow:ellipsis; text-align:left">
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style="padding:6px 12px 6px 0px">
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<div><favicon.ico></div>
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<br>
</div>
<div>I really just need to prevent that initial thump.
I’ll pick up a relay if that is best. </div>
<div><br>
</div>
<div>Is there an easier solid-state solution? I don’t
mind adding another buffer stage at the output.</div>
<br id="x_x_lineBreakAtBeginningOfSignature">
<div dir="ltr">Benjamin Tremblay</div>
</div>
</blockquote>
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</blockquote>
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