[sdiy] Buchla 295 10-band comb filter topology

[Lanterman, Aaron D]

> On Nov 22, 2022, at 5:20 PM, Donald Tillman <don at till.com> wrote:

> Next question; how does that work?

Then there’s the ultimate question, I often ask when looking at Buchla circuits, which is: HOW DID DON COME UP WITH THIS? 

In some cases, it’s clear he had a basic vocabulary of circuits and generally plunked them down until he got the effect he wanted (there seems to be no effort to go back and simplify things, it seems he was more interested in moving on to something else), but there’s a lot of Buchlaland that just seems like it’s from another dimension.

There’s two main grand mysteries two me:

1) How did he come up with the “diodeless deadband circuit” in the 259 and Music Easel (I scoured three different books on nonlinear circuits/analog computing trying to find anything remotely like it), and

2) How did he come up with the Buchla 291 topology (I read on a forum that someone asked him and he said something along the lines that it was based on filters Max Matthews used in his vocoder work, but I was never able to find any more information about that to dig in further. 

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