Discussion about the Korg PolySix synthesizer

Whoa.  Other side of the board?  There's a cool idea!

Chip

--- In PolySix@yahoogroups.com, Murray <murray@...> wrote:
>
> no, don't use ceramic. Why don't you move the existing ones to the other 
> side of the board?
> 
> Just a thought
> 
> MH
> 
> On 4/05/2013 8:51 a.m., backshall1 wrote:
> >
> > According to Analog.com
> > http://www.analog.com/library/analogDialogue/Anniversary/21.html, you 
> > should
> > be using any of the "poly" (polystyrene, polypropylene, Teflon) types 
> > for a
> > sample and hold circuit, since a ceramic cap has considerable dielectric
> > absorption which can cause a type of charge memory that can cause 
> > errors in
> > hold level. Some polystyrene caps can be rather tall, so you would have to
> > choose carefully. The old mylars look like they are about 10mm high. The
> > caps I'm using on the clone boards are about 8mm, so there is not much
> > difference. How much clearance do you need for the new keybed? If the old
> > caps weren't soldered so close to the board, you could just bend them over
> > so they would lie flatter.
> >
> > Don B.
> >
> > _____
> >
> > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> 
> > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>] On 
> > Behalf Of
> > chipaudette
> > Sent: Friday, May 03, 2013 12:05 PM
> > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > Subject: [PolySix] Mylar caps on the sample-hold circuits on KLM-367
> >
> > Hi Folks,
> >
> > Some of you may know that I've replaced the keybed on my Polysix. The new
> > keybed has a long metal cross-bar that sits a little lower than the one on
> > the stock keybed. The new keybed is running into the tall 0.047uF 
> > Mylar caps
> > that are standing tall from the KLM-366. Specifically, I'm talking about
> > C31-C36 that are the caps that hold up the sample-and-hold output from 
> > IC29.
> >
> > Being too tall, I'm thinking about replacing them. They're listed as 50V
> > Mylar caps. Would it be OK to replace them with 50V ceramics instead? The
> > ceramics are WAY smaller and would allow my new keybed to fit easily.
> >
> > The signals being held by these caps is only used for the keyboard 
> > tracking
> > of the VCF, so it's not like I need a cap with ultimate fidelity. I think
> > that I need a cap that holds its DC value very well (which is the point of
> > the S-H).
> >
> > Would a ceramic be OK here?
> >
> > Chip
> >
> > [Non-text portions of this message have been removed]
> >
> > 
> 
> -- 
> Kind Regards<br>
> Murray<br>
> murray@...<br>
> www.paintingwithsound.co.nz<br>
> 
> 
> 
> [Non-text portions of this message have been removed]
>