Eagle for making guitar pedals PCB: getting started (part 1/3)

Sometimes, especially with complicated builds with a lot of components, or when you have to build several times the same pedal, it is easier to use a printed circuit board (PCB) than veroboard or turrets board. A PCB is easier to assemble, and it prevents from doing many mistakes that can occur when using veroboard: false contacts, misplaced component, complicated wiring involving a lot of wires...etc.

"Eagle" is the name of a beautiful animal, but it also stands for "Easily Applicable Graphical Layout Editor", the name of a famous software that helps you to conceive and make printed circuit boards (PCB). I already used it a lot to make PCBs. For instance, I made a few Klon buffer boards with it. I decided to write a serie of articles explaining how to use it to make PCB for your guitar pedals.

Article parts:
  • Getting started (you are reading this one now)
  • Tracing the circuit (to be published)
  •  Creating the PCB layout (to be published)

Eagle 
Become free to make PCB like you want with Eagle


Why using Eagle?

There are many different different software to create PCBs that are available nowadays: DipTrace, KiCad (open source), Express PCB, Fritzing... Why using Eagle instead of these ones?
Well, there are several reasons.

Eagle is free. If you are using Eagle for your personnal use, it is a freeware. Of course, there are limitations that come with the freeware version, but they are not really a problem when it comes to guitar pedal PCB development: maximum size of 100 x 80 mm (4 x 3.2 inches), which is really big for a guitar pedal PCB, only 2 layers maximum (well, we are not going to use more anyway), and one schematic maximum per project. If you want to sell your projects, you will have to buy it, but for simple projects like guitar pedals, the Lite edition is enough and costs only 69$! If you need to buy it, respect the developpers, do not be ill-eagle (badum tsss) and buy it.

Eagle is well documented. There are a lot of books, websites, videos that are dedicated to Eagle software. If you ever encounter a problem, or if you do not know how to use a precise function, you will always find a solution somewhere. I will write a list of useful websites down this post.

Eagle has the most complete libraries. When creating a PCB, you need to specify what component you are going to use in your circuit. Is it a small 1/8W resistor, a big 1W one?  Is it an electrolytic capacitor or a tantalum one? You can imagine that it is very important to precise it in order to have the good component "shape" on your PCB. In order to do that, you have lists of components that are called "libraries", which contains hundreds of different components! Eagle has a lot of libraries for all kinds of components, and some libraries had been made especially for guitar pedals!

Eagle is easy to use. Most PCB softwares are easy to use, and Eagle is too! The "graphical" word in "EaGle" simply means that you have a wysiwyg interface. The interface is easy to use, and let you directly move the components on the board. Last thing, it works on windows and mac, which is nice if you are using different operating systems.

Convinced? Let's get started!


Installing Eagle

Download Eagle on CadSoft website, and install it as a freeware (except if you are going to sell the PCBs you make with it)


The libraries

When you create a PCB, you need to be very precise about which component you are going to use. Indeed, if you put a wrong reference somewhere, the spaces between the lugs can be too short / too long, the component could be too big to fit the PCB...etc. For instance on this PCB:
Superfuzz PCB circuit board
You can see that every component fits perfectly its location on the PCB. This is because when conceiving the PCB, I used the correct references for each components.

A library is simply a list of components referencing components sizes, values and shapes. Eagle comes with already a lot of libraries pre-installed. Some of them will be really useful (Resistors, Capacitors, Inducors (RLC), transistors, supply...etc), some of them not (Zilog microprocessor devices?).

Some libraries had been created specially for guitar pedal PCB making:
Gauss Markov library: very easy to use library with a lot of useful components.
Madbean pedals library: Brian (owner of madbean pedals) made available libraries for making guitar pedal PCB.
I strongly suggest that you download these libraries. They are easy to use, and contains all the basic tools that you need for making guitar pedal PCBs.

To install a library, unzip the files, and copy the .lbr files in the "Eagle v7.2/lbr" folder. It is in the applications folder on mac, or in the program files folder on windows.

Then, open Eagle. You should have a window like this, which is the control pannel:
eagle control pannel
You can see that there is a "Libraries" folder that can be expended. It contains all the libraries that you have in the "lbr" folder, including the ones you just downloaded and copied.
To tell Eagle which libraries you are going to use, you need to expand the "Libraries" folder, click right on the library you want to use and click on "Use".
Eagle how to use librairies
You can see that you have a quick description of the library on the right. It can help you sometimes to choose whether you want to use a library or not.

Ok so the big question is now... Which libraries should we use? Either you can use every library, but you can easily get lost with the number of different components available, and redundancy of some components. In my experience, I only use a few libraries compared to what Eagle is offering... Guitar pedal making is quite simple electronics, and does not require a lot of differente components.
Here are the libraries that I use when making a PCB:
  • Gauss Markov libraries (all libraries)
  • Madbean libraries (all libraries)
  • belton-engineering.lbr (if you are using tubes)
  • con-jack.lbr (if you want to implement DC jack on your PCB)
  • diode.lbr
  • ic-package.lbr
  • led.lbr (you will only use LED3MM or LED5MM (classic 3 or 5 mm LED) or DUOLED if you want dual colored LED)
  • linear.lbr (IC, OP amps)
  • pot.lbr (potentiometers, nothing else you stoner!)
  • rcl.lbr (dream library with all resistors, capacitors, inductors)
  • regulators.lbr (voltage regulators)
  • supply1.lbr and supply2.lbr (mainly for the ground symbol)
  • switch.lbr
  • transistor-fet.lbr, transistor-neu-to92.lbr, transistor-npn.lbr, transistor-pnp.lbr, transistor-power.lbr, transistor-small-signal.lbr, transistor.lbr (you should have almost every transistor now!)
  • v-reg.lbr (voltage regulators)
OK! That is already a lot of components, and should be largely enough for any guitar pedal circuit! And if a component you absolutely need is missing from these library, do not forget that you can use other libraries, or download libraries online!

Now we are ready to start!
First we have to trace the schematic... in the next blog post!

If you have any question, do not hesitate to post a comment!
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    Relay bypass with anti pop system: noiseless and clickless true bypass

    Did you like my post about relay bypass? At least I did, and now I use it in almost all my pedals! Thus, they are longer lasting, and we avoid the mechanical noises of a 3PDT. However, I noticed something annoying: the relay bypass makes more "pop" noises than the 3PDT, especially with high gain circuits...

    Indeed, relays tend to switch from one state to another much quicker than big mechanical 3PDT switches, which causes the "pop" noises to appear. The gainier the pedal, the more it will amplify the pop and make it louder.

    So I adapted a system that I have found on Stompville that suppresses all these noises. Here is the result, with a (very) simple "before and after" video:


    Ultimate guide to guitar effect wiring: how to wire DIY guitar pedals properly?

    Your guitar pedal circuit is finally populated and ready to rock! However, you still have to solder all the wires... I noticed that it was during this step that beginners encounter most of the issues that go along with guitar effects making.

    Especially with veroboard, you can quickly get a huge mess of wires going everywhere in the enclosure, with the so-called "spaghetti wiring" that we all achieved at least once when starting to make guitar effects!

     

    Other Vemuram Jan Ray variants

    Since I designed my own Jan Ray circuit board, I assembled quite a few. The PCB is quite small, so I have made different variants of various sizes and colors, and I though you migh enjoy it. Here are some of them!

    Here is a Jan Ray in a beautiful "mirror" copper color:

    Why you should NOT paint your guitar pedal enclosures yourself

    I know this is a bit against the concept of DIY, but the more I am spray painting enclosures, the more I notice that the results are not as great as a commercialy available prepainted enclosures.

    First, sanding the enclosure is a long and painful task and is mandatory if you want a clean surface to paint on. Avoid the long long hours spent carefully polishing your enclosure !

    Then, a lot of thin layers are required if you want a proper painting, and most of the time, the painting will still be fragile and sensitives to shocks. I got craks or scratches on the paint really quickly... Nice if you want a beaten-up, vintage, relic look, but not if you want something really clean and durable. You will end up having something similar to the first tall font russian big muff that had paint quality issue:

    Big muff tall font low quality paint

    Tap tempo tremolo DIY: a complex project!

    I am currently prototyping a tap tempo tremolo that I conceived. It is quite a big project, and I have been working on it since nearly 6 months now! Like many guitarists, I really like the warm vintage sounds that you can achieve using tremolo (like in "Bang Bang" from Nancy Sinatra), but also the choppy madness that you can get with square waves, like in "Know your enemy" from Rage Against The Machine, or even weird stuff with high speed tremolos... A really cool effect!

    I play regularly in a band, and my point of view is that tap tempo is just absolutely needed for rhythmic effects like delays for instance. Thus, I decided to add one in my tremolo. It is not easy to implement a tap tempo, as you have to use digital circuitry, as we will see later... Here is my current prototype:
    DIY tremolo with tap tempo
    That is a lot of knobs! You can already notice that there are two footswitches: tap tempo (right side), and the true bypass footswitch that is a clickless relay bypass system! I used the relay bypass system that I conceived, which is completely silent, and more reliable than classic 3PDT true bypass. Indeed, 3PDT footswitches are the main reason for guitar pedal failure. The little switch in the middle of the two LED (bypass LED, and tempo LED) allows you to switch the pedal temporarily. This is nice to add some choppy stuffs while you play!