[sdiy] moog high pass flter

[benno]

excellent! i am starting to see understand what you were getting at.

i would have brought this back up earlier, but the girlfriend decided my
spare time be spent on things other than my buzz boxes.

on 1/1/03 10:31 AM, Osamu (Sam) HOSHUYAMA at houshu at rogers.com wrote:

> Hello List,
> 
> Happy New Year!
> 
> I put a new schematic to explain my idea to implement HPF input into
> the vertical ladder filter.
> 
> http://www5b.biglobe.ne.jp/~houshu/synth/index.html
> 
> Vcfv0212.GIF is the schematic.
> 
> Enjoy,
> 
> Sam Hoshuyama
> 
> "Osamu (Sam) HOSHUYAMA" wrote:
>> To minimize the influence on the pole of the top stage, the capacitors
>> to inject the HPF input should be twice as much as those of the other
>> stages, and the amplifiers (attenuators) to generate balanced signals
>> should have very low output impedance compared with the impedance of
>> the capacitors.
>> 
>> Actually, the attenuators can be implemented with capacitors not
>> resistors.  By using this technique, we'll be able to build transistor-
>> ladder Sallen-Key filters.  If I have time in the coming holidays,
>> I'd draw some schematics to explain the ideas.

i'm guessing k is determined by the gain of the ladder output buffer
correct?

b.