The conclusion of our 3-part series on how to design your own pedal PCB! As a reminder, this project is 100% free and open source for educational purposes. My goal is to give you the tools to design your own PCB and how to order them from JLCPCB. For more on that, see parts 1 and 2 here.
For those who want to skip straight towards buying the PCB from me like usual. I also am making that available in my shop!
Let's great straight toward the build documentation!
Building a Project Blue Book
My PCB has a few goals:
Top mount jacks
Design for 1:1 component selection of the original 90's Marsh Blues Breaker
Component footprint to allow "modern" or "boutique" component selection such as silver mica capacitors, WIMA box film capacitors, and an extra 100uF cap for the incoming 9v power.
Footswitch wiring options for 1:1 original (non-true bypass) as well as true bypass wiring.
The whole project can easily be ordered from Tayda but more specific component selection can be found in the Mouser BOM but you will need to source pots and other things in addition to the Mouser BOM.
**Note that B22K pots are kinda hard to find. I did find a UK supplier via eBay that is selling them. Alternatively, you can use W20K, B25k, or B20k pots and see if they measure close. Remember, pots are typically 20% tolerance so 25k is within the tolerance from 22k.
https://docs.google.com/spreadsheets/d/1vi_5NAsIAtzfFzf3CYWXHwJiX_kYIXQxXJTd5aJEQpI/edit?usp=sharing
The Tone Geek Touch
For a more boutique component selection. I recommend going with
500v silver mica capacitors for the 10pf and 47pf capacitors.
WIMA Box film capacitors for 10nF, 220nF, and the 100nF caps
Toggle switches to change the pedal from Mk1v1 or Mk1v2 component selection.
100uf 25v+ solid organic polymer filter caps.
Below is the drill template for the pedal if you drill yourself in a 125B enclosure. If you're using Tayda electronics to do the drilling for you, the BOM includes the drill template shared link.
As for wiring, you have two options. You can go with a more modern true-bypass or you can still with the original type of wiring. The only potential downside to the original wiring scheme is that the input to the pedal is always tapped into the circuit. The switch is basically toggling between the pedal output or the input output. The original pedal used a DPDT switch as well (not for my wiring) although smart people can adapt the wiring to achieve using a DPDT.
I hope you enjoyed this series and learned something from it!
-Ryan
