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.

Did you find this useful, fun, or entertaining?
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6 People Made This Project!

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50 Discussions

0
MrErdreich
MrErdreich

6 weeks ago

Another awesome project idea for my electronics class, thanks!

0
benzwahlen
benzwahlen

2 months ago

I'm trying this circuit out on a breadboard but I'm getting a loud persistent crackling through the amp. I've checked te wiring multiple times but not luck :( Does the circuit need to be shielded or something?

0
joelforth82
joelforth82

Question 3 months ago

If I'm not using a metal case, what should I connect with a wire?
Also, breaking Step 12: Build the Circuit into 2 or 3 steps would be really helpful.

0
_someone_
_someone_

3 months ago

Can we get some sort of a tone test? Basicly, I'm a guitarist and I love electronics, but before I do that I want to make sure the pedal soundes good. Thanks!

0
niklasstrassl
niklasstrassl

Question 10 months ago

Hi! I‘ve built everything acording to the instructions but all it does is to make the signal more silent. I think that i made a mistake with the grounding, but are there any other possible issues? The parts should be all ok.

0
randofo
randofo

Answer 10 months ago

It is hard to say anything for certain without seeing it. Did you try building it on a breadboard first?

0
DanielC561
DanielC561

Question 1 year ago

Hi! Amazing, its a really nice and fun project to do. It works ... but, for me it has a background noise, and the funny thing about it its that if i touch the metal case with mi bare hands, the noise stops. I think its a problem with the grounding, somebody had the same problem? Somebody knows a solution? In any case! Thanks randofo, amazing job! I really love your instructables!

0
randofo
randofo

Answer 1 year ago

Yes, that sounds like a grounding problem. I am not sure where the problem is originating without being able to see the wiring. Are the barrels of the jacks correctly connected to ground on the circuit...? Are you using a metal enclosure...? If you are using a metal enclosure, is the circuit board accidentally shorting on the casing...?

Also, can you please upload a picture and post an I Made It! comment? I like seeing what people are making. :)

1
DavidP820
DavidP820

Question 1 year 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
0
randofo
randofo

Answer 1 year 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.

0
DavidP820
DavidP820

Reply 1 year 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

01.jpg02.jpg03.jpg04.jpg05.jpg06.jpg07.jpg08.jpg09.jpg10.jpg11.jpg
0
DavidP820
DavidP820

Reply 1 year 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

0
DavidP820
DavidP820

Reply 1 year 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 :)

0
randofo
randofo

Reply 1 year ago

Sorry, just seeing this. You likely want a latching switch, not a momentary. This is easy to swap out.

0
DavidP820
DavidP820

Question 1 year 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 :)

0
randofo
randofo

Answer 1 year 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.

0
DavidP820
DavidP820

Reply 1 year ago

Thanks!

0
Reconsider59
Reconsider59

3 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!

0
randofo
randofo

Reply 1 year 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.