[sdiy] Buchla 295 10-band comb filter topology

[David G Dixon]

My advice (which you emphatically don't need) is to do a Fourier-domain
analysis of the circuit and plot amplitude vs frequency.  Maybe something
surprising will pop out.

  _____  

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of
Lanterman, Aaron D via Synth-diy
Sent: Tuesday, November 22, 2022 2:01 AM
To: synth-diy mailing list
Subject: [sdiy] Buchla 295 10-band comb filter topology


[CAUTION: Non-UBC Email]	
Does anyone recognize the topology Don is using here in the bandpass
sections? 

http://fluxmonkey.com/historicBuchla/buchlaFiles/Buchla_2950_200.jpg

The low and high bands are 3-pole Sallen-Keys, but I'm not sure what's going
on in the middle filters. It looks kind of like a multiple feedback filter,
but instead of having a resistor to ground like in Figure 1 here:

https://sound-au.com/project63.htm

There's some weirdness with a 3rd capacitor connecting to the resistive
feedback back.

Aaron Lanterman, Prof. of ECE, Georgia Tech
My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
My blog on Electronics and Programming: https://lantertronics.blogspot.com
My YouTube channel on Electronics and Programming:
https://www.youtube.com/c/lantertronics



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