<div dir="ltr"><div>Interesting article.</div><div><br></div><div>Since the seventies I used mica capacitors in industrial equipment operating in exigent conditions, temperature stability issues, among other reasons.</div><div>Filters, modulators, demodulators, VCOs, etc.</div><div>Equipment operating all the time without being almost never turned off and does not require calibration over time. I never had any problems caused by this parameter.</div><div><br></div><div>The only problem is price.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 15, 2016 at 12:06 PM, Ian Fritz <span dir="ltr"><<a href="mailto:ijfritz@comcast.net" target="_blank">ijfritz@comcast.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">You might want to look at the Pease article I linked to yesterday. The earliest concerns about soakage centered on high voltages and long times, so that's commonly what you hear about. But the effects can also be important for low level audio. In my S/H work I saw obvious soakage effects at msec times.<br>
<br>
Ian<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
On 4/15/2016 4:56 AM, Simon Brouwer wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
Why is soakage an issue in VCO's?<br>
<br>
My impression is that the time constant of the soakage effect is orders of<br>
magnitude longer than the period of audio range signals. If that is correct,<br>
soakage would not significantly affect the frequency stability of a VCO, or<br>
would it?<br>
<br>
Best regards<br>
Simon<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 15 April 2016 at 03:56 Ian Fritz <<a href="mailto:ijfritz@comcast.net" target="_blank">ijfritz@comcast.net</a>> wrote:<br>
<br>
<br>
Mica caps have too much dielectric soakage for serious use in VCOs.<br>
(See the famous Bob Pease writeups.)<br>
<br>
My super S/H project was started to compare soakage and leakage in C0G<br>
ceramics vs plastics. I found that C0G and polystyrene had nearly<br>
equivalent behavior. Other plastics, including PPE, were inferior.<br>
<br>
I'll say it again: C0G is the way to go for high-performance synth<br>
circuits, especially given their small size and reasonable cost.<br>
<br>
Ian<br>
<br>
<br>
On 4/14/2016 4:33 PM, Pete Hartman wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Film caps generally seem to be preferred, but I can't say I've heard any<br>
strong arguments for one type of film cap over another for that purpose.<br>
<br>
Thanks<br>
<br>
Pete<br>
<br>
On Thu, Apr 14, 2016 at 4:25 PM, David G Dixon <<a href="mailto:dixon@mail.ubc.ca" target="_blank">dixon@mail.ubc.ca</a><br>
<mailto:<a href="mailto:dixon@mail.ubc.ca" target="_blank">dixon@mail.ubc.ca</a>>> wrote:<br>
<br>
Yves suggests either polystyrene or silvered mica. I guess they're<br>
interchangeable...? I think silvered mica are easier to use (and to<br>
get).<br>
<br>
> -----Original Message-----<br>
> From: Quincas Moreira [mailto:<a href="mailto:quincas@gmail.com" target="_blank">quincas@gmail.com</a><br>
<mailto:<a href="mailto:quincas@gmail.com" target="_blank">quincas@gmail.com</a>>]<br>
> Sent: Thursday, April 14, 2016 2:15 PM<br>
> To: David G Dixon<br>
> Cc: Sdiy<br>
> Subject: Re: [sdiy] Silvered mica caps in VCO core integrators<br>
><br>
> I use polystyrene (as per Ray Wilson's instructions) but I'm<br>
> willing to bet Mica will be perfect as well. In fact I think<br>
> Yves Usson uses Mica for that in his VCO:<br>
> <a href="http://yusynth.net/Modular/EN/VCO/index.html" rel="noreferrer" target="_blank">http://yusynth.net/Modular/EN/VCO/index.html</a><br>
><br>
> On Thu, Apr 14, 2016 at 3:53 PM, David G Dixon<br>
> <<a href="mailto:dixon@mail.ubc.ca" target="_blank">dixon@mail.ubc.ca</a> <mailto:<a href="mailto:dixon@mail.ubc.ca" target="_blank">dixon@mail.ubc.ca</a>>> wrote:<br>
> > Hey team, what do we think about silvered mica caps in VCO<br>
> core integrators?<br>
> > I've used them in filters, and they work great. Any hidden<br>
> dangers I<br>
> > should be aware of?<br>
> ><br>
> > _______________________________________________<br>
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> > <a href="mailto:Synth-diy@dropmix.xs4all.nl" target="_blank">Synth-diy@dropmix.xs4all.nl</a> <mailto:<a href="mailto:Synth-diy@dropmix.xs4all.nl" target="_blank">Synth-diy@dropmix.xs4all.nl</a>><br>
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><br>
><br>
> --<br>
> Quincas Moreira<br>
> Test Pilot at VBrazil Modular<br>
<br>
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