[sdiy] Silvered mica caps in VCO core integrators

[Ian Fritz]

Mica caps have too much dielectric soakage for serious use in VCOs. 
(See the famous Bob Pease writeups.)

My super S/H project was started to compare soakage and leakage in C0G 
ceramics vs plastics.  I found that C0G and polystyrene had nearly 
equivalent behavior.  Other plastics, including PPE, were inferior.

I'll say it again: C0G is the way to go for high-performance synth 
circuits, especially given their small size and reasonable cost.

Ian


On 4/14/2016 4:33 PM, Pete Hartman wrote:
> Film caps generally seem to be preferred, but I can't say I've heard any
> strong arguments for one type of film cap over another for that purpose.
>
> Thanks
>
> Pete
>
> On Thu, Apr 14, 2016 at 4:25 PM, David G Dixon <dixon at mail.ubc.ca
> <mailto:dixon at mail.ubc.ca>> wrote:
>
>     Yves suggests either polystyrene or silvered mica.  I guess they're
>     interchangeable...?  I think silvered mica are easier to use (and to
>     get).
>
>      > -----Original Message-----
>      > From: Quincas Moreira [mailto:quincas at gmail.com
>     <mailto:quincas at gmail.com>]
>      > Sent: Thursday, April 14, 2016 2:15 PM
>      > To: David G Dixon
>      > Cc: Sdiy
>      > Subject: Re: [sdiy] Silvered mica caps in VCO core integrators
>      >
>      > I use polystyrene (as per Ray Wilson's instructions)  but I'm
>      > willing to bet Mica will be perfect as well.  In fact I think
>      > Yves Usson uses Mica for that in his VCO:
>      > http://yusynth.net/Modular/EN/VCO/index.html
>      >
>      > On Thu, Apr 14, 2016 at 3:53 PM, David G Dixon
>      > <dixon at mail.ubc.ca <mailto:dixon at mail.ubc.ca>> wrote:
>      > > Hey team, what do we think about silvered mica caps in VCO
>      > core integrators?
>      > > I've used them in filters, and they work great.  Any hidden
>      > dangers I
>      > > should be aware of?
>      > >
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>      >
>      >
>      > --
>      > Quincas Moreira
>      > Test Pilot at VBrazil Modular
>
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