Help on adding Low "Peak and Q" to pultec

I would like to turn the "Low" boost into something more like the "Hi-Boost" in that it is a peaking filter rather than shelving. I also would like to give it a "Q" function.

Here is my first attempt. Please find L5 and R11 at the bottom of the schematic.

I'll attach the simulation in the next post.

I really am unsure of what other things doing this my have an affect on... any thoughts would be greatly appreciated!

here is the sim of above circuit.

You need to think about R9 in your schematic. This resistor is what works the magic at the Lo end in the Pultec and causes the Pultec bump when you dial in max Lo boost and cut together. It is pretty vertain that it won't work the same if you change the way Lo boost is achieved.

Cheers

Ian

I played around with this some time ago - my conclusion was more or less that you'd need an inductor (a rather large one for low frequencies) in series with each of the 12 boost/cut capacitors. And then a Q pot common to all L/C's in boost, and one for cut.

Other solutions (that I could think of) tends to mess up functionality in the rest of the system.

Jakob E.

Thanks guys!

Do you mean like this? When I do that, it brings the HI frequencies back up...?

Maybe you mean something different?