Big Muff Workshop

Big Muff Workshop at NoiseBridge

You want o build a Big Muff, good for you! It’s not hard todo follow the steps below. 

If you’re using one of my PCBs the part numbers on the PCB correspond to the parts numbers on the schematics on this site: 

https://www.bigmuffpage.com/Big_Muff_Pi_versions_schematics_part1.html

There were many different versions of the Big Muff created by the Electro Harmonix company and more still created by others. The majority are all the same with only the part values changing. 

Take a look at the first schematic on the page linked above. Notice that 

R2 is 36K. Look at the second schematic, R2 is 33K. 

Most of the schematics are all exactly the same with the difference that the part values change. Notice that the schematics on this site all use the same part number for the part in the same position in the schematic. This not true for all schematics you will find on the internet! 

My PCBs use the part numbers for the schematics on the Bit Muff Page. This means you can build almost any version of the Big Muff with this PCB. 

I have added a couple extra parts.

• R1 1M – This is to prevent popping when the effect is switched to bypass. All modern guitar pedals include this!
• R24 3k3 – This is current limiting resistor for the LED. The original Big Muff did not include an LED. You can use any value from 470r to 10k for this. It will determine how bright the LED lights up when the effect is on. 
• D5 1N5817 – Was added to protect the circuit in case it is connected to a reverse power supply. All modern pedals have something like this. 
• D6 LED – This is the LED, it lights when effect is turned on. You can use any LED for this. The Anode should go in the square hole. The anode has the longer leg, and the LED has a flat side that represents the cathode. 
• R25 100r – Is a current limiting resistor, and is part of the reverse polarity protection scheme. 
• C14 47µ – Is for power filtering. If you have a noisy power supply this will hopefully remove the noise. 

Follow these steps: 

• Find a version of the Big Muff that you plan to build. If you’re not sure which one, there are a lot to choose from, build the “V1 “STANDARD” TRIANGLE BIG MUFF PI “ its number 6 in the list. 
• The next step is to source parts.
  • You can use parts from the Noisebridge electronics room. You’ll have to search for them using the database.
  • You can order parts online from:
    • Tayda Electronics 
    • Stompbox Parts
    • Or search the Noisebridge parts database to find parts in the Noisebridge electronics room.
  • The Sustain, Tone, and Volume potentiometers need to be the 9mm types, like this or this.
  • You’ll need an enclosure. You can use one like this, or this. Or put your pedal in anything you can find that it will fit inside, see this post.
  • You’ll need two 1/4″ jacks. Anything will work. if you’re not sure get this or this.
  • You’ll also need a foot switch. You need 3PDT type, like this, or this.
• Once you have parts the real work begins! The goal is to identify the part number and the value. On the schematic mentioned above, R2 is 33k. You need to solder a 33k resistor into the spot labeled R2 on the PCB. Repeat the process until all of your parts are placed!
  • Be careful to solder the correct value into the correct location! This is a typical step where beginners make mistakes! 
  • 33Ω, 33k, and 33M are all different values! 
    • 33Ω = 33 ohms
    • 33k = 33,000 ohms (k = x1,000, k times thousand)
    • 33M = 33,000,000 ohms (M = x1,000,000, M times million)
  • Some parts are polarized, it matters how they are oriented in the PCB! This includes the diodes, LED, and some of the capacitors. For the diodes there will be stripe on the part, align that with the stripe on the PCB. For the LED the long leg goes in the square hole. For Caps C14 will have a longer leg and the part will have a stripe on one side, the long leg goes in the square hole, this will have + on the PCB. 
  • If you have any questions feel free to ask me over the Noisebridge discord Pedal Building channel. 

Here is an image the Big Muff that I showed at the workshop today, if you started building from that schematic here it is if you need it for reference:

See this page for more info on drilling and wiring: http://www.super-freq.com/pcb-projects/build-your-favorite-big-muff/

Here is a link to the next event.