[sdiy] popping a cap into a VCO

[harrybissell]

<blonde mode on>

I don't understand all the "rap talk"...

who would want to "pop a cap" into a VCO ???

Doesn't that mean shooting the VCO.  That would
sure make its output DC if you know ehat I mean...

H^) harry (aka 'Scope doggy-dog :^)



john mahoney wrote:
> 
> > without seeing the SCHEMATIC :^) I can't say for sure...
> 
> Ain't gonna happen! ;-)
> 
> There is a PCB layout in the datasheet, but that's all:
>     http://www.synthesizers.com/datasheets.html
> The VCO is the Q106, and the cap is shown at the bottom left (the board is
> shown upside down, actually).
> 
> Funny thing: The datasheet shows a 4700 pF cap but the actual caps say
> "10000J" on them. I took that to mean 10000 pF, since the only styrenes I've
> seen are the Xicons which max out at 10000 piffs. Not that it matters, in
> this case.
> 
> > Leakage 'might' be a problem in the larger sizes... if so the oscillator
> > will stall at really low frequencies.
> 
> Ah. My guess was that the waveshapes might be deformed due to leakage, and
> I'll stick with that guess under the assumption that stalling would be the
> extreme case.
> 
> > Get the best cap you can for the application...
> 
> Well, from what I read online (a Field Guide to Capacitors, probably written
> by some amateur hack) polypropylene seems to be a good choice in this case.
> ;-)
> --
> john