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What someone could try is to take one of those $1 8 pin SMD MCUs (STM32 or ATTiny/PIC) which has an internal temperature measurement as these are usually pretty accurate, then create a small program that keeps it at a particular elevated temperature by using
low power programmable wait periods, then epoxy it onto the top of the expo transistors. Finally wire the VCC and GND to the MCU by flying leads.
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of René Schmitz <synth@schmitzbits.de><br>
<b>Sent:</b> 11 October 2022 14:08<br>
<b>To:</b> synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
<b>Subject:</b> Re: [sdiy] expo pair "heat shield?"</font>
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<div class="PlainText">Hey Neil and all,<br>
<br>
In principle it's not a bad idea especially if the mass and hence <br>
thermal inertia of your device is small.<br>
<br>
E.g. a SMD dual transistor.<br>
<br>
<br>
I would vote against using regular silicone, the usual RTV stuff <br>
evaporates Acetic Acid, aka Vinegar. Viva la corrosión!<br>
<br>
<br>
Hot glue or Epoxy seem good options to me. I've used both in with THT <br>
parts.<br>
<br>
Mainly to mechanically couple tempco resistors to the dual transistor.<br>
<br>
I've also used heatshrink, and a dab of thermal paste to isolate the <br>
KTY-81 in my VCO3s to the 2SC1583s.<br>
<br>
<br>
Best,<br>
<br>
René<br>
<br>
<br>
Am 11.10.2022 um 07:23 schrieb Neil Harper via Synth-diy:<br>
> hey all,<br>
><br>
> just wondering if anybody thinks it's worth encasing an exponential pair<br>
> for stability. while this is in my modular case, there must be some heat<br>
> currents moving around from the other stuff that share the same space.<br>
><br>
> Maybe a dab of hot-glue-gun (hot snot), or a silicone or something?<br>
><br>
> I'd hate for it to bite me in the arse in the future, maybe corroding<br>
> the copper traces or the tin legs or becoming impossible to remove. What<br>
> do the pros use?<br>
><br>
><br>
> -- <br>
> /// Neil Harper<br>
> /// Every Wave is New Until it Breaks<br>
><br>
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