<div dir="ltr">Precision & Stability. In RF we need precision, that´s the reason to the use.<div>I also had no problems in AF circuits.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 15, 2016 at 1:29 PM, David G Dixon <span dir="ltr"><<a href="mailto:dixon@mail.ubc.ca" target="_blank">dixon@mail.ubc.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">That's what I wanted to know (but was afraid to ask). Silvered mica caps<br>
are more or less insisted upon in RF circuits. What becomes so bad in AF<br>
circuits?<br>
<div class="HOEnZb"><div class="h5"><br>
> -----Original Message-----<br>
> From: Synth-diy [mailto:<a href="mailto:synth-diy-bounces@dropmix.xs4all.nl">synth-diy-bounces@dropmix.xs4all.nl</a>]<br>
> On Behalf Of Simon Brouwer<br>
> Sent: Friday, April 15, 2016 3:57 AM<br>
> To: Ian Fritz; Sdiy<br>
> Subject: Re: [sdiy] Silvered mica caps in VCO core integrators<br>
><br>
> Hi,<br>
><br>
> Why is soakage an issue in VCO's?<br>
><br>
> My impression is that the time constant of the soakage effect<br>
> is orders of magnitude longer than the period of audio range<br>
> signals. If that is correct, soakage would not significantly<br>
> affect the frequency stability of a VCO, or would it?<br>
><br>
> Best regards<br>
> Simon<br>
><br>
> > On 15 April 2016 at 03:56 Ian Fritz <<a href="mailto:ijfritz@comcast.net">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<br>
> 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>
> > > Film caps generally seem to be preferred, but I can't say<br>
> I've heard<br>
> > > any strong arguments for one type of film cap over<br>
> 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">dixon@mail.ubc.ca</a><br>
> > > <mailto:<a href="mailto:dixon@mail.ubc.ca">dixon@mail.ubc.ca</a>>> wrote:<br>
> > ><br>
> > > Yves suggests either polystyrene or silvered mica. I<br>
> guess they're<br>
> > > interchangeable...? I think silvered mica are easier<br>
> to use (and to<br>
> > > get).<br>
> > ><br>
> > > > -----Original Message-----<br>
> > > > From: Quincas Moreira [mailto:<a href="mailto:quincas@gmail.com">quincas@gmail.com</a><br>
> > > <mailto:<a href="mailto:quincas@gmail.com">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<br>
> integrators<br>
> > > ><br>
> > > > I use polystyrene (as per Ray Wilson's<br>
> instructions) but I'm<br>
> > > > willing to bet Mica will be perfect as well. In<br>
> 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">dixon@mail.ubc.ca</a> <mailto:<a href="mailto:dixon@mail.ubc.ca">dixon@mail.ubc.ca</a>>> wrote:<br>
> > > > > Hey team, what do we think about silvered mica<br>
> caps in VCO<br>
> > > > core integrators?<br>
> > > > > I've used them in filters, and they work great.<br>
> Any hidden<br>
> > > > dangers I<br>
> > > > > should be aware of?<br>
> > > > ><br>
> > > > > _______________________________________________<br>
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> <mailto:<a href="mailto:Synth-diy@dropmix.xs4all.nl">Synth-diy@dropmix.xs4all.nl</a>><br>
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> > > ><br>
> > > ><br>
> > > ><br>
> > > > --<br>
> > > > Quincas Moreira<br>
> > > > Test Pilot at VBrazil Modular<br>
> > ><br>
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</div></div></blockquote></div><br></div>