[sdiy] HPFs and ADSRs

[Aaron Lanterman]

the MS-20 is the Bach version of a Sallen Key

Sent from my iPhone

On May 25, 2010, at 4:26 AM, "David G. Dixon"  
<dixon at interchange.ubc.ca> wrote:

>>> I also learned how annoying it would be to have only one envelope  
>>> for
>>> modulating both the VCF and the VCA, again from the MS-20.
>>> After I finish my preamp/envelope follower, I guess my next  
>>> project will
>>> have to be a couple of SVFs and a couple of ADSRs.
>>
>> Be aware that MS-20 highpass filter is quite different from SVF.  
>> Without
>> resonance, it's 1-pole highpass and increasing resonance shifts it
>> somewhat towards 2-pole.
>
> Yes.  I was looking at Rene Schmitz's clone, but it's a pretty weird  
> LP/HP
> topology, with the second stage fixed in lowpass mode, and the  
> resonance not
> seeming to be hooked up to anything in highpass mode (is this a  
> mistake on
> the schematic?).  I wonder how different it would sound from an SVF,  
> or even
> a simple cascaded-OTA (or cascaded-VCA) 2P HPF?  Any thoughts?
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy