Lithium Grim OmniMuff Building Instructions Download Page 4

OmniMuff v1.0 

 

Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the 

property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement 
is implied.

 

Build options 

 

This PCB can be used to mimic an extreme wide range of vintage to modern Big Muffs. In total 29 
versions of the original Version 1, 2, 3, 6, 7, 8 and 9 as well as some famous clones (EQD, Colorsound 
et

c.) can be built with just this single board. OMG, the stress of choosing which one to build….

 Buy 

more!! 

In the components section you will find the components needed for the different configurations. 

When it says “jump”, there is no component to be place

 

but instead you’ll need to connect both pad 

of the component with a jumper wire (eg a spare piece of lead wire you get when cutting a resistor 

to size). When it says “jump 1

-

2”, then you’ll need to connect pad 1 to pad 2 of the component with 

a jumper wir

e. With “

jump 5-6

” you’ll need to connect pad 

5 to pad 6 of the component with a 

jumper wire, etc. 

A dash (“

-

“) means there is no component 

nor jumper to be placed at that spot for 

that type of Big Muff. Just a few examples for switch 1 and 2: 

 

 

 

The PCB was designed to use PCB mounted potentiometers (

P1

-

P3

) on the back of the PCB, but you 

are free to use more traditional solder lug chassis potentiometers. Rectangular pad on the PCB marks 
pin3 and that corresponds with this numbering of the solder lugs: 

 

 

 

 

VR1 

is arranged as onboard trimpot on the PCB. This is done because for most people it is set and 

forget. However, you could choose to make it external by wiring a chassis pot. For this I added the 
pinout next to the trimpot pads so you know what pad to connect to which pin on the pot. 

Because the different Big Muff versions used a lot of different transistors, I marked the pinout on the 
PCB (EBC/CBE). Before you place a transistor, make sure the pins correspond to the letters on the 
PCB. I cannot stress this enough! Also note that 72#2 version 1 Triangle is a 

PNP

 effect that means 

that it needs 

-9V

 (positive ground). You can do this by simply reversing the black and red wire of the 

DC, but that also means you can not use it with a daisy chained power supply with other +9V effects 
or things will go really bad and I predict smoke will come out somewhere! I suggest you leave out the 
DC Jack in 

PNP

 versions of the Big Muff and only use a reverse wired battery. This way it can be used 

in a chain of +9V effects. 

SW1

 is added so you can switch the Colorsound Tonebender stage 1 diodes and caps in and out of 

the circuit instead of just leaving out the components. That way it is more versatile. This option is not 
mentioned in the component section as it is not part of the original! 

 

Summary of Contents for OmniMuff

Page 1: ...OmniMuff Building instructions V1 0 ...

Page 2: ...nt is implied 2 Table of contents PCB layout 3 Build options 4 Components 5 Transistors 5 Resistors and capacitors 5 Build sequence 6 Drill template 7 Off board wiring 8 Modifications 9 Troubleshooting 9 Schematic 10 Read this entire manual thoroughly before you start building the effect There are some available options and a lot of different configurations so you should choose which one you want ...

Page 3: ...or circuit identification and where applicable their trademarks are the property of their respective owners who are in no way associated or affiliated with the author No cooperation or endorsement is implied 3 PCB layout Dimensions 75 mm x 45 5 mm 2 95 inch x 1 79 inch ...

Page 4: ... P3 on the back of the PCB but you are free to use more traditional solder lug chassis potentiometers Rectangular pad on the PCB marks pin3 and that corresponds with this numbering of the solder lugs VR1 is arranged as onboard trimpot on the PCB This is done because for most people it is set and forget However you could choose to make it external by wiring a chassis pot For this I added the pinout...

Page 5: ...etween 160 and 200 Resistors and capacitors Ok this is going to get me some hate mail I found no real tonal difference using vintage carbon composition resistors or modern metal film resistors I am NOT a certified electrical engineer so this is based on simply experimenting Ditto goes for the capacitors I used mostly WIMA SMF and electrolytic capacitors from Panasonic and they sound great everywhe...

Page 6: ... each different type you use For this reason I marked the pinout on the board for your convenience I also added a graphic line to indicate the flat side of the transistor when using a TO 92 This is based on the 2N5088 transistors Other types possibly need to be rotated Always consult the datasheet of the transistor and orient accordingly Now continue by soldering the small capacitors MLCC then the...

Page 7: ...ied 7 Drill template 29 6 mm 29 6 mm Volume Tone Sustain Footswitch 15mm After you drilled the enclosure you can insert the potentiometers and attach them firmly to the enclosure Now insert the PCB on the pots and if all fits ok you can solder the potentiometers to the PCB If you want to incorporate SW1 and SW2 as an external switch you can place them wherever you want Just measure before you dril...

Page 8: ...lmost all LEDs 9V The sleeve on the output jack is not connected on purpose Make sure the output jack is in good electronic contact with the enclosure else you can try and connect the sleeves of the input and output together If you test the unit outside of an enclosure you need to connect the output sleeve to ground Note that there are two 9V pads on the board You may only use 1 at a time else you...

Page 9: ...em on the PCB itself The board is not working at all what now Check if your 9V is plugged in correctly and or soldered correctly on the board Pay special attention to the polarity Check that you oriented the capacitors IC s transistors and diodes the right way SMF MKT and ceramic capacitors as well as resistors do not need to be oriented A likely sign of incorrect capacitors and or orientation is ...

Page 10: ...es are mentioned solely for circuit identification and where applicable their trademarks are the property of their respective owners who are in no way associated or affiliated with the author No cooperation or endorsement is implied 10 Schematic ...

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