can someone run a simulation for me of the DOD Bifet tone control?

[Derringer]

you'd have my eternal internet gratitude 

I ask because in a FB group I'm part of, there's lots of raving about this particular pedal and how great/useful its tone control is.
It looks like it boosts bass on one end and then boosts treble on the other end. I'm curious what the frequencies being boosted are, and just in general what it looks like on a frequency plot.



Thank you kindly if you can oblige.

[Groovenut]

you'd have my eternal internet gratitude 

I ask because in a FB group I'm part of, there's lots of raving about this particular pedal and how great/useful its tone control is.
It looks like it boosts bass on one end and then boosts treble on the other end. I'm curious what the frequencies being boosted are, and just in general what it looks like on a frequency plot.



Thank you kindly if you can oblige.

Here you go! I think a log pot may be called for though. It bunches up at one end with a linear pot.

[Derringer]

thank you Groovenut!

I was pretty sure that it did shelves at the extremes but didn't realize that it attenuated bass and treble (although not by a whole lot) in the middle spot!

[mth5044]

I like that. Thanks for sharing!

[Derringer]

cool little tone circuit, right?

the pedal was apparently designed to be used by acoustic-electric players, check out the huge 4m input impedance designed to accept a piezo pickup

[samhay]

It's a cool circuit that I have been meaning to build for quite a while.

In addition to the weird tone control, the first stage is quite neat too - it's a high-impedance non-inverting gain stage with gain of about -10db to +10-dB.

Here is another sim of the frequency response with the Tone pot set to 0, 10, 50, 90 and 100% rotation.
The blue trace is taken from the (+) input of the second op-amp. Note the (probably unintended) low-frequency boost from the gain stage.

[Derringer]

Nice.  Thanks Samhay!