[sdiy] cem-3396 questions

[Jim Patchell]

Atom 'Smasher' wrote:

> does anyone know where i can find out more about the filter design of the
> CEM-3396?
>
>         http://www.synthtech.com/cem/c3396pdf.pdf
> the block-diagram on the data sheet just shows at as 4 amps in series,
> controlled by a mystery module, and somehow decoupled by capacitors.

    Not decoupling capacitors....these set the resonant frequency in
combination with the tuning current.

>
>
> how do the capacitors affect the sound?

    By selecting the capacitor you will affect the overall tuning range.  If
you make the capacitors larger, you will tune over lower frequencies.  Make
it larger, it will tune over higher frequencies.

    As far as the sound quality, the capacitor type will have some affect,
but probably very small, to the point where if you use ceramic vs
polystyrene, you will probably not notice the difference.

>
>
> what is the box [e^x] below it?

    This is a voltage to exponential current converter.  This is what tunes
the filter.

    Hope this helps, a bit...

    -Jim

    Visit: http://www.silcom.com/~patchell