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<div class="moz-cite-prefix">On 28.04.2024 11:11, Ingo Debus via
Synth-diy wrote:<br>
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cite="mid:7670A839-D8E5-48BD-AC34-3099472F964A@gmail.com">
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<div class="">Am 25.04.2024 um 09:54 schrieb René Schmitz <<a
href="mailto:synth@schmitzbits.de"
class="moz-txt-link-freetext" moz-do-not-send="true">synth@schmitzbits.de</a>>:</div>
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<p
style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"
class="">I would have used two NMOS in anti-series
instead.</p>
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What is also puzzling me: why are there two anti-pop circuits? The
only reason for two series resistors (instead of just connecting
both tip and ring via a single resistor to the amp output) I can
think of is that there’s still some signal at the tip when a mono
plug is inserted. But why two MOSFETs? Using a single resistor
instead of R646/R647 and a single MOSFET would have done the trick
too, no?</blockquote>
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<p>The two resistors; I would also say this is to keep it mono
compatible. And to delimit the current in and out of the jack. <br>
</p>
<p>My conjecture would be that in the evolution of the design they
first had the two resistors, and then on a later revision the
mosfets . <br>
</p>
<p><br>
</p>
<p>You can do this with a single FET, but it needs to have lower
Rds(on), and maybe not a jellybean SOT-23 part anymore.</p>
<p>If you use a single 2N7002 then the maximum attenuation becomes
an issue. Rds(on) is 2ohms. <br>
</p>
<p>Which is in the same ballpark of the other resistors, i.e. the
muting isn't going to be 100%. It keeps ~1/10th of the signal when
muted.<br>
</p>
<p>Assuming you replace the two 22 ohms by 10 (or 11) ohms and a
single FET, you have only an attenuation of ~1/5th. <br>
</p>
<p><br>
</p>
<p>Best,</p>
<p> René<br>
</p>
<p><br>
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<pre class="moz-signature" cols="72">--
--
<a class="moz-txt-link-abbreviated" href="mailto:synth@schmitzbits.de">synth@schmitzbits.de</a>
<a class="moz-txt-link-freetext" href="http://schmitzbits.de">http://schmitzbits.de</a></pre>
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