reducing the mid-scoop on a Big Muff Pi tone stack

[mordechai]

I seem to remember a comment posted a while back that in the BMP tone stack, you could reduce the midscoop by replacing one of the 39k resistors (can't recall which one!) with a 100K resistor.  I'm not talking about the (admittedly cool) modification to the tone stack circuit by Jack Orman where an additional pot controls the "body" of the scoop...just the actual transistor that needs to be replaced to accomplish this.  Would appreciate help on this, or on locating the thread if anyone can find it.  Would also be interested in knowing WHY the replacement reduces the scoop.

[armdnrdy]

Here's the link for the tone stack calculator that someone posted for me. (thanks again!)

http://www.duncanamps.com/tsc/

It includes the big muff tone stack. Click on the component values to change them.

Try different values and you'll learn quite a bit.

[darron]

like armdnrdy says, play with the TSC to shape it how you'd like it.


what exactly do you mean by reducing the mid scoop though? the mid scoop is a character of the tone stack.

replacing the 39k with 100k would only make the scoop even deeper it would seem to me. you could replace it with a 10k or so if you wanted the mids to dip less.


let us know what you decide to do and what changes you make (:

[frequencycentral]

Make both resistors 27K, both caps 33n and it gets flat, with bass boost at one end and treble boost at the other.

[R O Tiree]

Here's one I made earlier...



This gets you the mid-scoop characteristic of yer average BMP... or not, depending on where you have the switch. Only one component to switch in and out 

[Electron Tornado]

Here's the link for the tone stack calculator that someone posted for me. (thanks again!)

http://www.duncanamps.com/tsc/

It includes the big muff tone stack. Click on the component values to change them.

Try different values and you'll learn quite a bit.

+1 on the tone stack calculator.

Here's an article that might help as well:  http://guitarkitbuilder.com/content/big-muff-pi-mod-more-mid-range-tone

[deafbutpicky]

look here for even more

http://www.muzique.com/lab/tone3.htm

[pinkjimiphoton]

the tone stack calc was invaluable in making my icbm.

mictester at the other forum helped me get that together, but i didn't like the tone stack. i wanted something much
smoother in sweep... i think i had to change like one component or something. changed the whole personality of the fuzz!