DIY Guitar Pedal

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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.

2 People Made This Project!

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41 Discussions

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DavidP820

Question 27 days ago

I can't get it right and don't know why...
I think I did everything as you wrote, but no matter what I do there is no fuzz. I get sound, but no effect...
could be related to the type of audio jacks that I have?

20190322_214044.jpg20190322_214132.jpg
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randofoDavidP820

Answer 27 days ago

1) Did you build the circuit first on a breadboard to confirm all of the components are working...?

2) Yeah... that is probably the problem... that is not a stereo jack. It is a mono jack with a switch. That unfortunately won't work as a power switch. That type of jack is meant to connect / disconnect the guitar signal from the circuit.

3) See if you can bypass that jack and power the circuit directly from the battery. It should work.

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DavidP820randofo

Reply 26 days ago

I didn't build it on a breadboard because I don't have one. It happend twice with two sets of components so I don't think that one of them doesn't work (but who knows). I connected the lines in my board like they would be connected in a breadboard (where there were connections to be made...), I added a picture.

I also tried connecting the battery directly to the board, but I got the same results.

I attached pictures to explain what I did with hope you can find where I messed up...

P.S
I tested it without connecting it to the metal case, but I connected both of the audio jacks' barrels together with a wire during the testing. When I tried connecting the battery directly to the board I test it with the two barrels connected and without this connection. Still got the same result

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DavidP820DavidP820

Reply 26 days ago

One more thing,
I reviewed the schematics again and found out that I forgot to connect the circuit to ground at one point, but after connecting it I tested again and no change

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DavidP820DavidP820

Reply 26 days ago

WOW!!!
OK I'm very sorry for all the nagging. I figured it out!
It sounds amazing, THANK YOU!

Now I have another problem, It's the Stomp Switch...
The effect is only on when the switch is pressed (so I have to press it the entire time I'm using it).
I checked the order page on the site where I bouht it, it says that it's a "momentary" switch...

And I added an LED that works forever because I couldn't think of a way to only make it work when the line goes through the circuit, but it's still cool :)

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DavidP820

Question 27 days ago on Introduction

The capacitor in the link is 50V. I only have 16V/25V/400V... Will one of them work?
I have no clue about it as you can probably tell :)

2 answers
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randofoDavidP820

Answer 27 days ago

A capacitor's rating is the max voltage it can handle, and not connected to how much voltage it is providing. For instance, if you have a 9V battery, your capacitor just needs to be greater than 9V.

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Reconsider59

2 years ago

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!

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randofoReconsider59

Reply 2 months ago

You would put an LED and appropriate resistor (probably 220 ohms or greater) in series between power and ground on the circuit board. When the board gets powered up, the LED will turn on.

As a rule, I typically don't add LEDs. It's just an aesthetic choice for me.

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Morgogh

2 months ago

How would one go about using a 9v dc adapter rather than the battery?

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Donald Bell

2 years ago

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!

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randofoDonald Bell

Reply 2 years ago

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.

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randoforandofo

Reply 2 years ago

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

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Yogi70randofo

Reply 2 years ago

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.

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ThothLoki

2 years ago

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.

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randofoThothLoki

Reply 2 years ago

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.

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16jwilliams

2 years ago

thanks for the instr