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Hi, i made the kit leeds fuzz 2 month ago, i play a lot with this pedal, the power of fuzz is heavy and you can have a "wall of sound" easely. but there is a problem with the treeble, i have always to downgrade and put more and more bass on my amp. the sound is too high, sharp...
so i would like to mod this pedal, adding a pot which can control the tone. In addition, i think i could have a sound very similar to the famous pedal ibanez OD 850 and ibanez OD 9 if i can control the tone.
so a little help to localise the part to change in the PCB (i think about a resistor may be ???) will be very interesting for me !
sorry for my english...
pixe

i found some information on http://www.beavisaudio.com/techpages/Pots/

...
someone can help me to find exactely where i have to insert this ?

The Leeds fuzz has two tone shaping elements - one set by C2 (rolls off treble) and C3 (rolls off bass) in the pre-amp section (Q1 & Q2) and a notch filter (C12 & C13, -20dB at 1000Hz) for a scooped sound that is switched in by the tone switch.

Of course C2 and C3 filter before clipping and the notch filter is after clipping.

To cut the treble as you want perhaps the simplest thing to do is to place a capacitor - try a 0.01uF or 0.022uF - across R23 (a 0.01uF rolls off everything above 650Hz). This will give you a treble cut sound on one switch position and the original scooped sound on the other switch position.

You could replace R22 and R23 with a 50K log pot (an 'audio' pot) and connect perhaps a 0.022uF from the wiper of the pot to circuit ground if you want a variable control.

hi tark, thanks for your coment, i will try this week end

Sorry, just realised I could have been clearer in my last post.

R22 47K and R23 10K reduce the unfiltered volume. So to convert those to a treble control you really want to keep R22 as it is, replace R23 with a 10K audio pot and take the wiper of that pot to ground through a 0.47uF capacitor. The anti-clockwise of the 10K pot goes to R22. You can connect the clockwise of the pot to its wiper (as well as to the 0.47uF)

This arrangement is similar to the tone control on a guitar.

For more extreme tone shaping you might consider getting a graphic EQ. There is a JOYO pedal - the 6 Band Equalizer - that is very good for the money if you can find one. It is a Chinese made clone of the MXR M109.

is there a difference (maybe in volume ???) between your solution and the schem on beavis site , the "big muff pi" tone control ?

What I described in my last post is a simple way to add treble cut to the Leeds Fuzz.

The Beavis diagram is for a general purpose passive tone control (using a lot more parts). I'm guessing the idea of the Beavis (I'm assuming this from the diagram you posted above) is that you build it into its own little box which you can add to your effects chain wherever you like. To work properly it needs to run from a relatively low impedance and into a fairly high impedance. As far as I can tell the control gives you a treble boost (which you don't want) at one end of its rotation and a treble cut at the other.

ALL tone controls have an effect on volume. In my suggested mod you should have enough gain after my tone mod to adjust overall levels using the Balance control on the Leeds Fuzz.

Hello everyone,
Interested in this thread, as I have a Leeds Fuzz that I love but it's too harsh in the treble for my live amp set up.

Has anyone done this mod? How much does it tame the treble? Does this affect the octave note in there?

All I would have to do is replace the one cap with a .01uF? I am not interested in adding a tone control knob, just wanted a quick fix to mellow the treble a bit.

Thanks,
F

Ah, too bad about good old Tark. A great source of information, but....

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