<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p>There's also a full chapter on a FET compressor design in another
of his books 'Self on Audio' (Chapter 10, if I remember right)</p>
<p>I didn't realise there was a 3rd edition of Small Signal Audio..
Great book!<br>
</p>
<div class="moz-cite-prefix">On 05/05/2021 13:24, ulfur hansson via
Synth-diy wrote:<br>
</div>
<blockquote type="cite"
cite="mid:57249460-4FCB-4C1A-9442-84531FCCFF5E@gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
slightly OT, has anyone successfully built the FET compressor
douglas describes?<br>
<br>
<div dir="ltr">sent from outer space</div>
<div dir="ltr"><br>
<blockquote type="cite">On 5 May 2021, at 11:32, Neil Johnson
via Synth-diy <a class="moz-txt-link-rfc2396E" href="mailto:synth-diy@synth-diy.org"><synth-diy@synth-diy.org></a> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">
<div>It's still chapter 26 in the third edition. Also read
through the first half of chapter 18 on line inputs.</div>
<div><br>
</div>
<div>Neil</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, 5 May 2021 at
11:34, Mike Bryant <<a
href="mailto:mbryant@futurehorizons.com"
moz-do-not-send="true">mbryant@futurehorizons.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div lang="EN-GB">
<div class="gmail-m_-7715839508084510931WordSection1">
<p class="MsoNormal"><span
style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)">Small
Signal Audio Design (I have Second Edition so it
may have moved chapter)</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)"> </span></p>
<div>
<div style="border-color:rgb(181,196,223)
currentcolor currentcolor;border-style:solid none
none;border-width:1pt medium medium;padding:3pt
0cm 0cm">
<p class="MsoNormal"><b><span
style="font-size:10pt;font-family:"Tahoma","sans-serif""
lang="EN-US">From:</span></b><span
style="font-size:10pt;font-family:"Tahoma","sans-serif""
lang="EN-US"> Tom Wiltshire [mailto:<a
href="mailto:tom@electricdruid.net"
target="_blank" moz-do-not-send="true">tom@electricdruid.net</a>]
<br>
<b>Sent:</b> 05 May 2021 11:17<br>
<b>To:</b> Mike Bryant<br>
<b>Cc:</b> synth-diy francesco mulassano via<br>
<b>Subject:</b> Re: [sdiy] Differential amps
and noise cancellation in dsPIC 33FJ128GP802
uP's DAC</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<div>
<p class="MsoNormal">The circuit is straight out
of Microchip’s datasheet and is what they
recommend. But that’s not to say that it can’t
be improved!</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Which Douglas Self book did
you mean? He’s written a few.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal"><br>
<br>
</p>
<div>
<p class="MsoNormal">On 5 May 2021, at 11:11,
Mike Bryant <<a
href="mailto:mbryant@futurehorizons.com"
target="_blank" moz-do-not-send="true">mbryant@futurehorizons.com</a>>
wrote:</p>
</div>
<p class="MsoNormal"> </p>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)">You
probably want to use something a little
more complicated for the best
performance. Douglas Self covers this
well in Chapter 26 of his book.</span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)"> </span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)"> </span></p>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)"> </span></p>
</div>
<div>
<div style="border-color:rgb(181,196,223)
currentcolor currentcolor;border-style:solid
none none;border-width:1pt medium
medium;padding:3pt 0cm 0cm">
<div>
<p class="MsoNormal"><b><span
style="font-size:10pt;font-family:"Tahoma","sans-serif""
lang="EN-US">From:</span></b><span
class="gmail-m_-7715839508084510931apple-converted-space"><span
style="font-size:10pt;font-family:"Tahoma","sans-serif""
lang="EN-US"> </span></span><span
style="font-size:10pt;font-family:"Tahoma","sans-serif""
lang="EN-US">Synth-diy [<a
href="mailto:synth-diy-bounces@synth-diy.org"
target="_blank"
moz-do-not-send="true">mailto:synth-diy-bounces@synth-diy.org</a>]<span
class="gmail-m_-7715839508084510931apple-converted-space"> </span><b>On
Behalf Of<span
class="gmail-m_-7715839508084510931apple-converted-space"> </span></b>Tom
Wiltshire<br>
<b>Sent:</b><span
class="gmail-m_-7715839508084510931apple-converted-space"> </span>05
May 2021 10:17<br>
<b>To:</b><span
class="gmail-m_-7715839508084510931apple-converted-space"> </span>synth-diy
francesco mulassano via<br>
<b>Subject:</b><span
class="gmail-m_-7715839508084510931apple-converted-space"> </span>[sdiy]
Differential amps and noise
cancellation in dsPIC 33FJ128GP802
uP's DAC</span></p>
</div>
</div>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Hi all,</p>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">The dsPIC 33FJ128GP802
uP (and others in the family) includes a
16-bit DAC on the chip. The outputs from
the DAC are provided as a differential
output to help cancel any noise generated
by the uP internally. NOt a bad idea,
seeing as that is probably inevitable.
Despite this precaution, the DAC is
reasonably noisy and not suitable for all
applications.</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">The example circuit for
combining the differential outputs is
shown attached - a simple diff amp with
10K resistors everywhere.</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">Now, my question is
this:</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">If I change the gain of
the differential amp by increasing R6/R8
(to 47K, say) does this affect the noise
cancellation properties of the diff amp?</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">It seems to me that it
might, because the positive input now has
a different proportion of signal going to
it than the negative input.</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">Thanks,</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal">Tom</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
<div>
<div>
<div>
<div>
<p class="MsoNormal">==================<br>
Electric Druid<br>
Synth & Stompbox DIY<br>
==================</p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><image002.png></p>
</div>
</div>
</div>
</div>
</div>
</div>
<p class="MsoNormal"> </p>
</div>
</div>
</div>
_______________________________________________<br>
Synth-diy mailing list<br>
<a href="mailto:Synth-diy@synth-diy.org" target="_blank"
moz-do-not-send="true">Synth-diy@synth-diy.org</a><br>
<a href="http://synth-diy.org/mailman/listinfo/synth-diy"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://synth-diy.org/mailman/listinfo/synth-diy</a><br>
Selling or trading? Use <a
href="mailto:marketplace@synth-diy.org" target="_blank"
moz-do-not-send="true">marketplace@synth-diy.org</a><br>
</blockquote>
</div>
<span>_______________________________________________</span><br>
<span>Synth-diy mailing list</span><br>
<span><a class="moz-txt-link-abbreviated" href="mailto:Synth-diy@synth-diy.org">Synth-diy@synth-diy.org</a></span><br>
<span><a class="moz-txt-link-freetext" href="http://synth-diy.org/mailman/listinfo/synth-diy">http://synth-diy.org/mailman/listinfo/synth-diy</a></span><br>
<span>Selling or trading? Use <a class="moz-txt-link-abbreviated" href="mailto:marketplace@synth-diy.org">marketplace@synth-diy.org</a></span><br>
</div>
</blockquote>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
Synth-diy mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Synth-diy@synth-diy.org">Synth-diy@synth-diy.org</a>
<a class="moz-txt-link-freetext" href="http://synth-diy.org/mailman/listinfo/synth-diy">http://synth-diy.org/mailman/listinfo/synth-diy</a>
Selling or trading? Use <a class="moz-txt-link-abbreviated" href="mailto:marketplace@synth-diy.org">marketplace@synth-diy.org</a>
</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
BugBrand LTD
UK company No. 07199808
VAT No. GB 988 2629 57
1 Ninetree Hill
BRISTOL BS1 3SB
United Kingdom
<a class="moz-txt-link-abbreviated" href="http://www.bugbrand.co.uk">www.bugbrand.co.uk</a></pre>
</body>
</html>