DIY Guitar Pedal

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Introduction: DIY Guitar Pedal

About: My name is Randy and I am a Community Manager in these here parts. In a previous life I had founded and run the Instructables Design Studio (RIP) @ Autodesk's Pier 9 Technology Center. I'm also the author ...

Making a DIY guitar fuzz pedal is a fun and easy electronics weekend project for hobbyists and guitarists alike. Making a classic fuzz pedal is much easier than you think. It just uses two transistors and a handful of other components. Aside from sharing the schematic, throughout this project I will also be going over basic tips and tricks for guitar pedal construction.

If you would like to learn more about electronics and reading schematics, check out the free Electronics Class!

Step 1: Materials

For this project you will need:

(x1) Hammond BB metal enclosure
(x2) 2N3904 transistors (or equivalent) *
(x1) 22uF capacitor
(x1) 0.1uF capacitor **
(x1) 0.01uF capacitor **
(x2) 100k resistors ***
(x1) 10K resistor ****
(x1) 5.1K resistor ***
(x1) 5K potentiometer
(x1) 100K potentiometer
(x1) DPDT heavy duty push switch
(x1) PCB
(x1) 9V battery plug
(x1) 9V battery
(x2) 1/4" stereo jacks
(x2) Dial plates
(x2) Knobs
(x2) Velcro squares
(x1) 3M 30-NF Contact Cement
(x1) Drilling guides (download and print)

* Different NPN transistors create slightly different sounds. Feel free to experiment on a breadboard with the circuit before you build it.

** The 0.1uF and 0.01uF capacitor can also be swapped out for slightly different values to create different sounds. Again, experiment on a breadboard before you solder anything in place.

*** Carbon film resistor kit. Only kit necessary for all labeled parts.


Please note that some of the links on this page contain affiliate links. This does not change the price of any of the items for sale. However, I earn a small commission if you click on any of those links and buy anything. I reinvest this money into materials and tools for future projects. If you would like an alternate suggestion for a supplier of any of the parts, please let me know.

Step 2: Attach the Drilling Guides

Cut out the drilling guides and attach them with masking tape centered upon the top and side faces of the enclosure (as appropriate).

Step 3: Mark the Centers

Mark the centers of each hole using a punch (or a nail if you don't have one).

Drill pilot holes for each marking using a 1/8" drill bit.

Step 4: Drill 9/32" Holes

Widen all of the holes in the enclosure with a 9/32" drill bit (or appropriate for you potentiometers).

Step 5: Drill 3/8" Holes

Widen the holes in the side of the enclosure using a 3/8" drill bit.

Also, widen the center hole in front of the enclosure with the same drill bit.

Step 6: Drill a 1/2" Hole

Finally, widen the center DPDT switch hole in the front of the enclosure with a 1/2" drill bit. You will likely want to clamp the enclosure down to your work table (or in a vise), before you drill this hole. A 1/2" drill bit can be aggressive.

Step 7: Mark the Mounting Tabs

Insert the potentiometers into their front mounting holes backwards and upside down.

Wiggle, them back and forth, and notice you have scratched a line on the surface that corresponds to its mounting tab.

Drill a 1/8" hole along this line just to the left of the larger potentiometer mounting hole.

Step 8: Create a Stencil

Lay one of the front dial plates on a piece of painters tape.

Trace and cut out its outline.

Step 9: Place the Template

Center the front plate atop one of the potentiometer holes.

Place the tape template down around it, and stick it to the front surface of the enclosure.

Step 10: Glue Down

Apply contact cement to the center of the stencil and also the back of the front dial plate.

Wait for it to dry long enough to become tacky to the touch.

Once dry, press the dial firmly to the enclosure to glue it in place.

Step 11: Repeat

Repeat the process for the second dial.

Step 12: Build the Circuit

Build the circuit as specified in the schematic. For now, do now worry about wiring jacks, potentiometers, or anything else that might not attach directly to the circuit board.

This circuit is basically a 2-transistor gain circuit and a variation on the classic Fuzz Face guitar pedal. To learn more than you ever wanted to know about this circuit, check out R.G. Keen's Technology of the Fuzz Face article.

Step 13: Wire the Potentiometers

Solder 5" green wires to the center and right-hand pin (if the potentiometer knob is facing you) on both potentiometers.

Also solder a 5" black wire to the remaining outer pin on the 100K potentiometer.

Step 14: Mount the Potentiometers

Mount the potentiometers to the enclosure by inserting it's shaft up through the hole in the enclosure, and fastening it in placing with its mounting screw.

Step 15: Wire the Power and Jack

Connect a 5" black wire to the terminal connected to the center barrel jack.

Connect the black wire from the 9V battery clip to the terminal connected to the smaller signal tab.

Finally, connect a 5" green wire to the terminal connected to the longer signal tab.

Step 16:

Mount the jacks and potentiometers to the inside of the enclosure using their mounting nuts.

In my pedal, the input and gain pot will be on the left of the pedal, and the 100K volume pot and output jack will be on the right.

Step 17: Mount the Switch

Mount the switch to the enclosure using its mounting hardware.

Step 18: Wire the Switch

Connect one of the switch's center pin to the green wire connected to the audio / power jack.

Wire the other center pin to the identical pin on the other audio jack.

Wire together one set of outer pins.

Solder a wire between the remaining pin in-line with the output jack to the center pin on the volume potentiometer.

Finally, solder a green wire to the remaining free pin. This will later be attached to the circuit board.

Step 19: Ground Connection

Connect the black ground wire from the volume potentiometer to the terminal on the audio jack connected to the barrel.

It is important to understand what is happening here, and that it will only work with a metal enclosure. Basically, since the other jack is using the barrel connection as a switch for the ground, the entire case is electrically connected to the ground plane. Thus, the barrel jack on the other jack is also connected to ground. So, by connecting the potentiometer to it, you are effectively connecting it to ground on the circuit board (without actually attaching it to the circuit board).

Step 20: Wire the Circuit Board

Now is time to attach the components mounted to the enclosure to the circuit board.

The red wire from the 9V power clip should go to the power rail, and the black wire from the stereo jack should be attached to the ground rail.

The gain potentiometer should be attached as specified in the schematic.

Lastly, the remaining unconnected switch wire in-line with the input should be connected to the input on the circuit, and remaining wire from the volume potentiometer should be connected to the output on the circuit board.

Step 21: Velcro

Attach the circuit board to the bottom of the enclosure using self-adhesive Velcro tabs. This both holds it in place,
and prevents it from touching the lid and shorting the circuit.

Step 22: Shut the Enclosure

Plug in the battery if you have not done so already and fasten the lid onto the enclosure using its mounting screws.

Step 23: Attach the Knobs

Turn the potentiometer knobs counter clockwise until they stop turning.

Place the knobs in place with their pointers pointing at the starting position on the dial.

Fasten the knobs in place with their set screws.

Step 24: Plug In

You are now ready to plug everything in and rock out.

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    29 Discussions

    Thanks for posting this! I love the aesthetic of the pedal, and a fuzz face clone will definitely be a welcome addition to my board!

    Have you considered adding an LED, to indicate when the pedal is activated? I'm doing a little research to figure out how to add one on my own, and will post info if I figure it out, but I'm new to circuit-building and worry I'm going to screw it up. If anyone has any ideas on this, please add them!

    Beautifully done! Can you drop in a link on where to pick up those awesome dial plates? A link for those knobs would be great too. Thanks!

    3 replies

    Ah yes. Forgot to put in links! Will get on that in the next day or two. In the meantime, the dials are from Amazon, and the knobs are from Small Bear Electronics. Nevertheless, I will get some links in there soon.

    On second thought, changed my mind. Just buckled down and put all the links in right now.

    Very new to this would it be possible to get more pictures of how everything is placed in the breadboard. I am just not seeing the layout would like to try this with my son.

    Can you give some more detail on the stomp switch? Is it latching or momentary? Your ible talke about the outside terminals and inside terminals. According to the pictures, are you wiring them up to the N/O or N/C? I am sure it doesn't matter, but I am curious.

    I know electronics decently, I am just not a music guy. I am hoping to build this for my father who loves to jam out on the guitar.

    1 reply

    It is latching. There is a link in the materials list.

    The jacks get wired to the two center pins. Beyond that, it doesn't matter which set of outer pins you use. One set is always closed to the center pins when the other set is open.

    thanks for the instr

    how does it sound?

    Nice project, especially the orange enclosure!

    Interesting that you put the input on the left and output on the right. All three pedals I'm currently using (TC Electronics Polytune, MXR Variphase, Exotic XW-1 Wah) all have their inputs on the right and outputs on the left. Your design would screw up the pattern, at least in my case. Any reason you went that way?

    9 replies

    Don't think electricity cares if it travels left to right or right to left. When you build it just swap the jacks to whichever side of the box makes you feel all worm and "fuzzy".

    It does matter which side you plug in your guitar and which side you plug the amp. Its not going to work if the signal goes in the wrong way. it is supposed to enter through the Base of the transistor. However If you really want the input jack on a certain side, just put it there. Some pedals have the jacks on the back of the box.

    It's not about "warm (not worm) and fuzzy". It's about uniformity with other pedals... obviously you can swap the jack positions but I was wondering if he had a reason for his decision.

    I agree. Why are the jacks backwards?

    That doesn't matter. If you put this on a pedal board, you'd want the input and output jacks to be uniform.

    Maybe, the guy means, since he is left handed, he does stuff backwards(though I can't speak for him). I know I'm left handed and have to double check, so I don't do stuff backwards. I think it was just a little mistake, we all make them. It's part of learning

    Nope. Just how I decided to do it when building it. Would be easy enough to reverse. Just flip the wiring connection from the jacks to the switch.

    Okay. Just wondering if you had a specific reason. Anyone who follows this might not figure that out until after they have built it, so I wanted to ask and bring that up in case anyone else might be building this to work with other pedals in an effects chain.