[sdiy] Synthacon/Steiner-Parker VCF inputs

[Derek Holzer]

Hi Laurie,

forgive my limited understanding of how a pulldown works, but wouldn't 
this work only with an open collector buffer? In the Synthacon circuit, 
there are several other resistors after the input which would form a 
voltage divider with the pulldown resistor and end up diverting some of 
the input signal to ground.

I believe Marc has used the same schematic as the 2nd version of the CGS 
clone:

http://www.cgs.synth.net/modules/pic/schem_cgs35_syntha_vcf_r1.gif

And I see in this schematic that each input has a resistor to ground 
early on somewhere in its path already. But these won't fill the same 
function you have just described will they? They look to my eyes more 
like some part of an RC network.

But if your idea is correct for this situation, what might be a safe 
pulldown value to add after the inputs?

D.

Laurie Biddulph wrote:
> I would have thought a weak pulldown resistor would be enough to keep 
> the floating inputs `not floating' without adding any significant 
> loading to signals that are injected

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