[sdiy] HPFs and ADSRs

Aaron Lanterman lanterma at ece.gatech.edu
Sun Jun 6 07:10:54 CEST 2010


On May 25, 2010, at 7:36 AM, Antti Huovilainen wrote:

> On Tue, 25 May 2010, Aaron Lanterman wrote:
> 
>> the MS-20 is the Bach version of a Sallen Key
> 
> Only the first version. The second version is better understood as combination of 1st order lowpass and low/highpass filters.

By first version, do you mean the Korg-35 IC version, and by second version, do you mean the LM13600 based version?

That second version can be understood that way - it gives insight into how it works - but it does look like a "Bach" version of a Sallen-Key (where there are two buffers instead of one) to me. At least that's what I've been calling it in lecture, and giving homework assignments on... :)

Search on "Bach" on this page: 

http://schematica.com/resources/A_list_of_active_filter_circuit_topologies.htm

Is there a difference between that and the MS-20 filter that I'm missing?

(Note above I'm talking specifically about the lowpass filter.)

- Aaron


More information about the Synth-diy mailing list