Showing posts with label Tips. Show all posts
Showing posts with label Tips. Show all posts

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!

     

    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

    Black Arts Toneworks Pharaoh Fuzz clone

    I want to make  Big Muff variants using my Coda Effects Big Muff PCB, and show you how to make them yourself. Lets start with the boutique version of the Big Muff that made it popular again on the stoner / doom scene: the Pharaoh Fuzz! Produced by Black Arts Toneworks since 2011, it was an immediate success because of the huge, warm, doomy sounds it can produce.

    Here is my version:
    Pharaoh Big Muff clone
    As you can see, the Pharaoh has more controls than a classical Big Muff. There are the classic gain / volume / tone controls, like a classical Big Muff, plus a few other options. Here is the original version of the Pharaoh:
    Black Arts Toneworks Pharaoh Fuzz
    There are a "high" potentiometer that allows us to set the amount of trebles, and two switches. The first switch is a 'high / low' switch, that allow us to have 2 types of gain settings for the pedal: low gain and high gain. It modulates also a bit the trebles. Finally, you can choose the type of diodes in the last distorsion stage with the second switch: classic silicon diodes, no diodes or germanium diodes!
    Black Arts Toneworks Pharaoh Fuzz clone
    Finally, there are some modifications on the circuit. For instance, input and output capacitors are 10uF tantalum capacitors, which will let a looooot of bass go through the circuit!

    Here is a gutshot (yes, I had fun drawing this!):
     Black Arts Toneworks Pharaoh Fuzz clone
    You can see the tantalum capacitors that are drop-shaped. I try to avoid as much as possible to use it in my guitar pedals. They are not especially good for audio, expensive, and most of all there are not really "ethical friendly". Tantalum is produced from coltan, a mineral that is the root cause of many conflicts, especially in Congo. Illegal mines were opened without any regulation, degrading environment in an uncontrolled way, with many Human right issues (a bit of reading about that on wikipedia). Traceability is a big problem with electronics. Most of the time we do not know how, where or in what ecological context components are made... For tantalum capacitors, just know that they are easily replaceable by electrolytic capacitors.

    Wima capacitors are much better for that: they are made in Germany (and thus, their production must respect European ecological laws and regulations). This is why I try to use them as much as possible:
     Pharaoh Fuzz clone
    So, how can we make the Pharaoh from a classical Big Muff PCB?

    Here is the schematic from the Big Muff page:
    Pharaoh Fuzz schematic
    As you can see, it is very similar to the Big Muff circuit! We can use the Coda Effects PCB and modify it following the above schematic. Here are the modifications to do:
    - no mid knob, 470k for R5.
    - no R2 resistor (we will use a switch instead)
    - no D1/D2 diodes (switch here too)
    - no R8 resistor. (replaced by a "high" potentiometer)
    No big changes!

    If you want, Rullywow sells a PCB especially conceived to make the Pharaoh Fuzz, named "King Tut". If these mods seems a bit difficult to do, you can buy this PCB to make it easier ! Rullywow creates really nice PCB, and this one is no exception, and is of very nice quality.

    First, we will remove the mid knob by placing jumpers on the mid knob pads, like indicated on the build document.

    To include the switches, we will have to use a 125B enclosure, it will not fit in a 1590B. We will have to use long lugs potentiometers to place switches so they do not touch the circuit board and create false contacts.

    For R2 and D1/D2, we will use switches:
    - SPDT on-on for choosing R2
    - SPDT on-off-on to choose D1/D2 diodes.


    Choosing R2: switching between the Hi/Lo setting of the Pharaoh

    We use a "on-on" SPST. Signal arrives to the center of the switch, and goes through a resistor, 39k ("high" setting), or 390k ("low" setting):
    Pharaoh mod
    Try to make the connections on the other side of the PCB, it will be simpler. With this switch, you can choose the R2 value! In "high" position, there will be a lot of gain and trebles, whereas in "low" position, the sound will have more bass, less trebles.

    It can apply to any resistor in the circuit, so feel free to experiment! Of course, some resistors are more interesting than others... I let you try!


    Diodes choosing: 3 positions switch

    We will use the same system for the diode switch. We are going to use a 3 positions on-off-on SPDT switch in order to have: germanium diodes (3 to have assymetric clipping), no diodes or classic silicium diodes. The second set of diodes to replace is D1/D2:
    There it is! We have our two switches. Beware of false contacts with these switches: try to reduce the length of naked cables.Voilà ! On a déjà nos deux switchs !


    Treble potentiometer

    Last mod to add to have exactly a circuit like the original design: the treble potentiometer. In fact, you just have to replace R8 (tonestack resistor) by a 25k potentiometer. Just connect the lug 1 and 2 to each pad of the R8 resistor:
    Pharaoh mod
    It can also apply to any resistor! You can investigate to find your favorite resistor to modulate ;)
    There it is! Voilà! We have got our Pharaoh Fuzz PCB!

    You can solder the other potentiometers now.  Beware: if we use "classic PCB-mount" potentiometer, the switches will not fit in the enclosure (they will touch the PCB and create false contacts). We will have to use "long lug" potentiometers like this ones:
    long lugs potentiometer
    You can also use classic potentiometer and make the lugs longer with soldered wire with solid copper wire or cur resistors / diodes lugs for instance.
    long lugs potentiometer solder

    You can now drill the 125B enclosure, and rock! :)
    Have fun!

    To go further:
    Official Pharaoh webpage : if you are interested in buying the original pedal
    Veroboard version of the pharaoh: a bit annoying and complex to make, but doable!
    King Tut PCB: dedicated PCB conceived by Rullywow

    Relay Bypass: conception and relay bypass code

    You might already have heard about "relay bypass", or even used it without knowing it. It a different true-bypass system than the classical 3PDT switch. Instead of using a mechanical 3PDT switch, a soft switch, a microcontroller and a relay are combined to turn the effect on and off.

    Relay bypass PCB DIY

     So... Why bother? My 3PDT switch is great, don't you think?

    As you may already know, 3PDT switches are the main cause of guitar pedal failure. These switches are not particulary though, and they often break, especially as we smash it continuously with our feet on stage.

    A classical high quality 3PDT switch is rated for 30,000 activation cycles. With relay bypass, we use a relay that will play the mechanical role of connecting ins and outs. Relays are usually rated between 10 and 100 millions cycles! Thus, this system is much more reliable.

    Moreover, the soft switch that we use to activate the guitar pedals also last longer than a 3PDT, usually around 50,000 cycles! They are also easier to replace, as there are only 2 connections to make with the relay bypass system, and not the full 3PDT wiring.

    This blog post will present you how does it work, and how to make your own relay bypass system using a microcontroller, from the beginning to the end! Long stuff (but good stuff?)!