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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.

 

Modifications 

 

There are so much tweaks made to the Big Muff, it is almost impossible to write them all down. This 
PCB by itself is actually one big modification of the 

Big Muff. But… have a look at the great work Coda 

Effects did by gathering a lot of tweaks: 

https://www.coda-effects.com/2015/11/big-muff-mods-and-tweaks.html

 

And if you go

ogle “Big muff mod” you will also find a ton of mods.

 

 

Troubleshooting 

 

All PCB’s have been

 100% factory e-tested and out of every batch I receive I build an effect to double 

check, so there should not be a connection problem 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 when an effect is sputtering, rumbling or 

“motorboating”.

 

 

Check if you used the correct values of the components. For resistors you can look here: 

http://www.diyaudioandvideo.com/Electronics/Color/

  

 

Double and triple check your soldering! A loose or cold solder can be really bad for your 
board. 

 

Replace the IC and/or transistors, one might be defective. Before doing that first unplug the 
9V and wait for 5 seconds. 

 

Check that you have good/high grade components. A lot of Chinese sourced parts are fakes 
(especially high end opamps, audio capacitors, vintage diodes and transistors) so be careful 
that you source your parts from reliable suppliers. 

 

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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