Created Appendix A: Printed circuit boards (markdown)

Appendix-A:-Printed-circuit-boards.md

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+# Buying boards from us
+
+Getting the Ploopy Headphones boards made can be complex, and expensive, especially if you only need one set. [That's why we sell kits with everything you need to build a set of Ploopy Headphones](https://ploopy.co/product-category/headphones/). Here's why that's great for you:
+
+- You get a PCB that is soldered, tested and programmed
+- It'll cost a hell of a lot less than if you do a production run of PCBs just for yourself
+- You won't have to order components and wait while they come in
+- We guarantee that it works
+
+Just something to consider. You're smart. You'll figure it out.
+
+# Making your own boards
+
+Want to make your own Ploopy Headphones boards? Great! Less work for us. Seriously, though, only choose this option if you know what you're doing. You don't want to embarrass yourself, do you?
+
+## Step 1: Order the PCBs from a PCB production company
+
+Here are the most important configurations you'll need to communicate to the company:
+
+*Amplifier board*
+- 6 layers
+- FR-4, TG 150-160 (basically, whatever the cheapest option is)
+- 1.6mm thickness
+- 1oz copper thickness for both outer and inner layers
+
+*Planar driver board*
+- 4 layers
+- ENIG surface finish
+- No stiffener
+
+If something is missing from here, it's not really important.
+
+At some point, you'll have to upload design files to the production company. Use the source files to generate your manufacturing files. If the production company rejects this package, however, you'll need to address the issue yourself.
+
+## Step 2: Order the electronics components
+
+All of the components are described in the schematics of the PCBs. Ordering the components is left as an exercise for the reader. Every component is available through resellers such as Digikey or Farnell; there aren't really any exotic electrical parts that are difficult to acquire.
+
+A complete list of all of the components can be found in the electrical design files.
+
+## Step 3: Get the necessary tools
+
+- Amplifier board
+- Planar driver board
+- All of the electronics components
+- A soldering iron
+- Solder
+- A printout of the schematics
+
+Schematics can be found in the source.
+
+## Step 4: Solder the components to the boards
+
+Once you've got the PCBs and all of the components, print out the schematics. Use the schematics to match the reference designators on the PCBs to the reference designators on the schematics, and then get to soldering.
+
+If you've never soldered surface mount components before, or want a refresher on how to solder, we recommend [this video on using an iron to solder surface mount components](https://www.youtube.com/watch?v=3NN7UGWYmBY), and [this video on using a hot-air soldering station](https://www.youtube.com/watch?v=c_Qt5CtUlqY).
+
+## Step 5: All done!
+
+Congrats, you finished assembling the electronics! Pat yourself on the back.
+
+You'll need to program the microcontroller before it works. Head over to [Appendix C: Firmware programming] to get at it.