Shelf/bell topologies in SVF parametric EQs

[atavacron]

Makes sense. What about the switching for the shelf? Mind annotating that?

Oh i understand. Just do exactly what it says in the note below the schematic; the flying leads are there to grab. Don’t forget to release the ground tie and the 2K Rg from the output inverter if you use it as a HP buffer. Post #64…

 

[dogears]

this is why we make schematics. im too lazy to parse those notes. at least put net names or something on them. (ie connect a to b).

 

[atavacron]

im too lazy to parse those notes.

I will keep this in mind for the future.

 

[user 37518]

Being older than I care to divulge, I have forgotten the pertaining demonstration. I wish someone could link me to it.

I remember seeing it in Sedra's book (not the ubiquitous Sedra/Smith book on Microelectronics, but the filter book), I will provide the derivation whenever I have a bit of free time.

 

[atavacron]

Sedra's book

Filter Theory and Design: Active and Passive
Sedra & Brackett 1979

I'm not finding a PDF in the first three pages of Google results, but it is Available at the Internet Archive

 

[user 37518]

Filter Theory and Design: Active and Passive
Sedra & Brackett 1979

Available at the Internet Archive

That's the one, it is mentioned in one of the first chapters IIRC, but I don't remember if the full-fledged derivation is in there. I will have to check my library whenever I have more time.

 

[atavacron]

I will have to check my library whenever I have more time.

I'll be interested to know what Sedra said about the DABP since I'm messing around with that in another thread.

 

[abbey road d enfer]

I'll look into Kicad.

I mentioned it because I know it has many good features and I know several people who use it profitably, but TBH I never succeeded in making it work satisfactorily for me.
I know LTspice on Mac is questionable.