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<p>The linear portion of the expo convertor is not relying on a
characteristic of the transistors that is temperature dependent so
it should be fine. The will still be a little temperature drift
because of the resistors, but that will be nowhere near the
3300ppm you get from transistors.<br>
</p>
<p>--tr</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 11/14/2016 11:17 AM, Justin Owen
wrote:<br>
</div>
<blockquote cite="mid:582a0dbd.46bb1c0a.fd42e.08e7@mx.google.com"
type="cite">
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charset=windows-1252">
I went with the adapted Electronotes design because I'm using the
full, temperature compensated exponential version on another
project - it seemed like a good idea to stick with one circuit
that I knew worked.<br>
<br>
The linear version I'm using is driving a VCA - so it's not pitch
critical and I'm not seeing any temperature effects under normal
use (unless e.g. I hold the circuit under a heater or some
such...)<br>
<br>
...but I was still curious if there was the possibility of
temperature compensation on the linear parts.<br>
<br>
Thanks,<br>
<br>
/ J <br>
<br>
-----Original Message-----<br>
From: Nathan Trites [<a class="moz-txt-link-abbreviated" href="mailto:nathan@idmclassics.net">nathan@idmclassics.net</a>]<br>
Received: 12.11.2016 18:37:15<br>
To: Justin Owen<br>
Cc: SDIY List<br>
Subject: Re: [sdiy] Linear current source - temperature
compensation?<br>
<br>
Is there any reason for sticking with the electronotes design? If
the<br>
tempcos are only there to compensate for the temperature effect of
the<br>
transistors, if you do away with the transistor pair altogether
theres no<br>
reason for them.<br>
<br>
- N<br>
<br>
<br>
<br>
On Sat, Nov 12, 2016 at 8:29 AM, Justin Owen
<a class="moz-txt-link-rfc2396E" href="mailto:juzowen@gmail.com"><juzowen@gmail.com></a> wrote:<br>
<br>
> Hello,<br>
><br>
> The classic Electronotes current source has a linear input.
It's possible<br>
> to chop out some of the exponential parts and just have a
linear current<br>
> source based on that design - however, you lose the two
standard Tempco<br>
> placement positions.<br>
><br>
> So - is it possible to temperature compensate a linear-only
current source?<br>
><br>
> 1) Please ignore the component values...<br>
> 2) I'm assuming the same temperature variation/dependance
exists in the<br>
> linear version...<br>
><br>
> <a moz-do-not-send="true"
href="http://www.sdiy.org/juz/source_exp.png">http://www.sdiy.org/juz/source_exp.png</a>
- exponential<br>
><br>
> <a moz-do-not-send="true"
href="http://www.sdiy.org/juz/source_lin.png">http://www.sdiy.org/juz/source_lin.png</a>
- adapted to linear only<br>
><br>
> Thanks,<br>
><br>
> / Justin<br>
><br>
><br>
><br>
> _______________________________________________<br>
> Synth-diy mailing list<br>
> <a class="moz-txt-link-abbreviated" href="mailto:Synth-diy@synth-diy.org">Synth-diy@synth-diy.org</a><br>
> <a moz-do-not-send="true"
href="http://synth-diy.org/mailman/listinfo/synth-diy">http://synth-diy.org/mailman/listinfo/synth-diy</a><br>
><br>
<br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
--Tim Ressel
Circuit Abbey
<a class="moz-txt-link-abbreviated" href="mailto:timr@circuitabbey.com">timr@circuitabbey.com</a></pre>
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