Guitar Fuzz Pedal PCB (first Version)

This is a tutorial to create a custom guitar fuzz pedal. This tutorial is different from other tutorials because it involves a completely custom printed circuit board (PCB). While most guitar pedals use traditional through-hole components (where each component uses wires to connect to other parts of the circuit), a PCB involves pre-traced copper routes. When mass producing boards, surface mount solutions take much longer to assemble, since components must be wired up by hand. PCBs allow machines to place the pedal components, making assembly much more uniform and much more scalable. We will walk through our design decisions for this PCB and show you how to create your own!

Supplies

Here are the components that we used for this initial design:

At the end, we will talk about what we would change in future iterations (hint: pick your item footprints very carefully!).

Step 1: KiCad Schematic

Download and install KiCad. There are a variety of tutorials online on how to install this software. It's free and open source, meaning that there is a large community that can add code and parts to a big library. This is what makes the design process so simple, since many parts are already online. Linked below is a tutorial to create schematics in KiCad. Essentially, pick the circuit that you want to design and emulate it on KiCad.

https://www.youtube.com/watch?v=7YNcZ0xUtr0&pp=ygUYa2ljYWQgc2NoZW1hdGljIHR1dG9yaWFs

Above is our simple fuzz schematic, picked from https://www.electrosmash.com/fuzz-face. This tutorial isn't meant to be a circuit design tutorial, so we recommend to look at other places to find circuit designs.

Step 2: KiCad PCB

Once you have a completed schematic, the next step is to link each component to a footprint. A footprint is simply a physical model that is attached to the electrical properties of the item in the schematic. You can create your own footprints, but it is much easier to attach ones made by other people.

Here is a link to create your own footprint, if the part you want isn't available in KiCad's library:

https://www.youtube.com/watch?v=znGD1Pdb0l4&pp=ygUYa2ljYWQgZm9vdHByaW50IHR1dG9yaWFs

Here is a link to attaching existing footprints to your design:

https://www.youtube.com/watch?v=Ghv0bGiZFL8&pp=ygUPa2ljYWQgZm9vdHByaW50

This is a full PCB design tutorial, which was very helpful for choosing specific things like trace sizing:

https://www.youtube.com/watch?v=aVUqaB0IMh4

Above is our PCB. We picked 0805 sized components (which are around the middle size for components). The project files are attached to this Instructable, so you can inspect the files for yourself.

Step 3: Ordering Components

Now that all the design work is done, you can begin to order your components. For the main circuit components, we recommend Mouser or DigiKey, since these large suppliers will have fast shipping and lots of stock. The ordering process for these components is pretty simple (just like buying from Amazon).

Make sure that you select the right component based on your footprint!!!!!

We made some mistakes in our ordering process which meant that we had to use traditional components for some of our parts.

The PCB ordering process is pretty simple too, but there are a few more steps. There are a lot of manufacturers but we recommend Osh Park since they allow you to upload your KiCad files directly to their site. This is a lot simpler than dealing with gerber files and other solutions. We chose a 2-layer PCB, since that was what our design called for.

The PCB will take a couple of weeks to ship, so make sure you order it as soon as possible. If you are ordering multiple boards, it gets much cheaper.

Note: Make sure to purchase a stencil with your order. This will greatly simplify the process of assembling the PCB. There will be a link to Osh Park's stencil division after you purchase the boards.

Step 4: Beginning Assembly

This is a relatively simple process, but there are many different machines to simplify the assembly. At this point, you will have your PCB, your components, and a stencil.

Start by taping your PCB to a surface.

Apply solder flux to all the pads of the PCB. This will come in a little marker-style bottle.

Step 5: Stencil

Next, tape your stencil over the PCB. Make sure that it is tightly secured and that the pads line up closely.

Wear gloves for this part, since the paste can contain lead.

Apply solder paste (which comes in another tube), to the metal and use the included scraper (or a credit card) to spread the paste over the mask. It should cover all of the pads of the PCB. It doesn't have to be perfect, but the paste should not overlap between the pads.

Step 6: Placing Components.

You can place the components by hand with tweezers or use a pick-and-place machine. At scale, an automated machine makes the most sense, but at low volume either works. The pick and place works by using a little vacuum to hold and release components.

Place the components on the board according to the schematic.

Step 7: Baking

Each oven will be different, but essentially you place your board inside the oven and select a certain 'recipe' which will set the temperature for a certain amount of time.

In the ND EIH, all the recipes are pretty similar so as long as you are reaching high enough temperatures, you can choose any recipe.

Make sure to wait until the board is cool (around 55C) before you remove it from the oven.

Step 8: Solder Through Hole Components

Some components, like many power adapters, are offered only in through hole configurations.

Solder the rest of the components as necessary by hand.

Here is a tutorial:

https://www.youtube.com/watch?v=Qps9woUGkvI&pp=ygUSc29sZGVyaW5nIHR1dG9yaWFs

Step 9: Enclosure

You can make an enclosure for your board if you want. We designed this in SOLIDWORKS and printed it.

Here is a quick intro:

https://www.youtube.com/watch?v=qtgmGkEPXs8&pp=ygUQc29saWR3b3JrcyBpbnRybw%3D%3D

Step 10: That's It!

Once you have your board assembled and in its enclosure, you're done! All you need is a power supply as dictated by your schematic and a guitar and you're good to go!