Adding a mid hump to a mid scoop tone control

[armdnrdy]

Do any of you DIYstompboxers know of a quick and dirty way of transforming the flat no mans land of a Big Muff PI type mid scoop tone control to include a mid hump without changing the characteristics of the high and low frequencies?

[Seljer]

the big muff EQ is basically a blend betweena high pass filter and a low pass filter. Depending on how much the seperate filters overlap, you get either a mid hump or a mid scoop.

Download this neat little program http://www.duncanamps.com/tsc/ and mess around with the values a bit to see what actually happens

[armdnrdy]

Seljer,

Thanks so much! I changed one cap to bring some body to the center of the pot. The top and bottom remain the same. Brilliant!

[Kesh]

You could try this big muff tone stack. Allows selectable very scooped, scooped (classic) or flat.

Maybe play with the flat C and R to get more of a hump.

[armdnrdy]

Hey Kesh,

Thanks for the reply and the schematic. I checked out BYOC's Large Beaver which is similar. (I don't really want to add another switch)

The tone control I'm looking to add some life to is the modified tone switching for the Jet Phaser. Mark Hammer pointed out that the Jet Phaser's tone stack is very similar to a Little Big Muff tone switch.

There is a 100K fixed resistor that only allows the choice of full treble or full bass. Mark suggested replacing the resistor and the switch with a potentiometer for a full tone control. There is one problem with that. With the mid scoop as it is, you still only have bass on one side and treble on the other attenuated, with anything in the middle cut. What that means sonically, is when you move from either side the volume drops a bit and there is no real tonal change until you get to the other side where the tone is attenuated again. Not much of a tone control!

I want to add the mid back in while keeping the original tone/frequencies of the Jet Phaser at the two extremes of the tone control. I used the Duncan Amps Tone Stack Calculator that Seljer provided a link for and got good visual results. I have to make the change on the build to hear where it is sonically. I may have to tweak the value of the cap up or down a bit to get optimum results. Unfortunately, I am not talented enough to hear frequencies in my head! but my ears still know when something sounds right. I'll let them be the judge.

[Derringer]

Do any of you DIYstompboxers know of a quick and dirty way of transforming the flat no mans land of a Big Muff PI type mid scoop tone control to include a mid hump without changing the characteristics of the high and low frequencies?

check out Jack Orman's take on adjusting mids in the BMTC
http://www.muzique.com/lab/tone3.htm