DIY Guitar Pedal Blog: Mojohand Iron Bell Fuzz

General

The Iron Bell is a big muff variant based on the P19 version of the muff

Here is a interesting link with a lot of schematics:
http://www.bigmuffpage.com/Big_Muff_Pi_versions_schematics_part4.html

In addition to the Big Muff there is a fourth pot for the mid range, called colour ;)

Schematic and BOM

This schematic ive found in the madbeanpedal forums posted by Matt (croquet hoop, thanks a lot).

They are similar with some minor differences to the P18 schematic from the bigmuffpage.com

-) P19: has the addiontal C16 (2.2nF) which adds high frequencies when the tone pot is down
-) P19: R2=33k, Iron Bell: R2=30k
-) P19: R22=140R, Iron Bell R5=120R
-) Iron Bell: additional R24=100R. Changes the high frequencies of the tone control top end

PCB

Currently there is no PCB for the iron bell available. I ordered a muff pcb from musikding.de and chnaged the parts accordingly and soldered the additional pot (colour) to the lugs of the C10 Cap (iron bell schematic)

My Build

I coloured the enclosure pink (using a spray finish) and put a waterslide decal on it, the use clear coat laquer spray.
The design of the waterslide decal was strongly influenced by the mojohand design.
I attached a PDF with my design.