[sdiy] Looking for 2164 12db/oct slopes bandpass filter design.. more detailed..

Tom Wiltshire tom at electricdruid.net
Sun Mar 9 18:02:08 CET 2014


No, Roman's design uses one more VCA per filter  because he's got voltage-controlled resonance too, not because his design does Bandpass as well. If you were happy with no VC resonance, you could use pots for resonance control, and do the design with one 2164. You'd still get the Bandpass output, because it's still a SVF.

Alternatively, you could use a LM13700 for the resonance VCAs for the two filters, although the 2164 VCA's log response is a good fit in this application and helps improve the linearity of the resonance control. Since this is still two chips not one, I don't see much advantage. Probably log pots would work well, though. That would make a very compact circuit.

HTH,
Tom


On 9 Mar 2014, at 16:39, "Jean-Pierre Desrochers" <jpdesroc at oricom.ca> wrote:

> Roman,
> 
> You are right when you say your design does HP and LP separately
> with their own CV's controls.
> But you are using 2 x 2164 in your design to do so (because you also do BP).
> My approach here:
> 
> Here is a possible 2 x 2 poles, 12db/oct bandpass design made of one 2164.
> http://www.arcenson.com/public/2164_BP_filter.JPG
> 
> But thanks for sharing..
> 
> JP




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