Parametric trap

[Blujay]

Very simple but works quite well. Have it in rather extreme cut just to show range potential

 

[madis64]

What would be its practical use?

 

[egellings]

Notch filter?

 

[madis64]

Notch filter?

Yet another one. What would be the usage case that is not covered by a gazillion of existing solutions?

 

[anibal]

The schematics is not drawn in a "conventional" way; but it is just a well known "T" filter.
😉

 

[Blujay]

Yes -- you could call it a notch filter -- very useful for eliminating mid range peaking in acoustic guitar and speaker cabinets

I like this one because it uses no op amp and has only one active element
Wien bridge network output inverted by Q2 and summed with in-phase signal
R15 and R16 is a dual tracking pot

 

[Blujay]

Thanks for the name -- just an idea of which more than likely has been thought of