In this article you will learn how to wire the jacks of a pedal and all the! And yes, unfortunately, we don’t hold everything on the PCB….
We will also teach you a lot of welding and wiring techniques. It is nevertheless essential to keep the adventure ! And then, when you have to wire, you also think about the ground loop…. Come on, let’s go!
- A soldering iron, for small budgets we offer this iron from the Japanese brand Goot which will be very useful for some kits from time to time.
- Tin! Tin! There is tin with 60% tin and 40% lead, which is easier to solder but very bad for the environment. If your iron is truly bad, go on over there (but it breaks my heart). Otherwise with a good iron like the ones we propose, use unleaded tin.
- A cutting pliers! A small dedicated clamp that perfectly fits the shape of the component legs. All we have to do is to cut it off!
- Something to strip a cable. It could be a cutter, a lighter, your teeth, all the tools MacGyver has found…. Or simply, a stripping pliers.
- A table, or a bench! Be careful the tin supplied creates small flux splashes. It stains and sticks….
- A tip cleaner, to clean your iron with a metal sponge that does the job perfectly.
- A third hand! Still a very practical tool at the end.
- A tip refresher. To have an iron that is constantly at its best!
- A nose pliers to bend your wires properly. Otherwise it also works with your fingers…
In a pedal you can find solid or stranded wire. This means that your signal goes through this conductor via one or several copper conduits. In high-frequency applications, the stranded wire is always preferred to avoid an edge effect that would produce losses. In this case, in the audio world, this effect is very strongly negligible since the frequency does not exceed 20kHz. So we simply have a lot of possibilities regarding our wiring wires. Having worked with both types, I can guarantee you that it is more pleasant to work with rigid wire, so solid wire. It folds, there is no need to tinplate it…
In terms of length, you don’t need to buy 30m reels to make a few pedals! All you need is a few wires from 7 to 10cm to connect the different components.
It is especially important to pay attention to the diameter of your cable to allow enough signal to pass through and avoid overheating. (This is especially true for your power connectors, if they consume a lot) We rely on AWG22 in to be very, very wide!
By repeatedly wiring boards we have defined our own color code so that we can easily find our way through them. You can choose to adopt it or not, it’s up to you! In any case, it is thoughtful to quickly identify a defect and then control the production quality of the device.
- The white is associated to the input signal, it is the one that enters the board. It is soldered to the board on the pad marked “I” for IN.
- Green is the color linked to the output, it is the signal that comes out of the board. It is connected to the pad labeled “O” for OUT.
- The red is the positive terminal of the 9V power supply of the board. It is connected to the pad marked “9V”.
- And the black for the ground, are to be welded on the pads “GND, G, G, G1 and G2” for GROUND.
prepare your cables
You must first equip yourself with a cutting pliers in order to cut them to the right length. Then, the cable end must be stripped on both sides. Then, bend the conductive part at 90°.
You have several options for stripping your cable. We show you here with a manual stripping pliers that we propose, and with an automatic stripping pliers. You understand that when you prepare dozens of pedals at the same time, at the rate of 5 wires per card, you like to have the luxury of an automatic stripper!
We will now solder them on the PCB. Be careful not to melt the wire jacket! Plastic can contaminate your joint and deteriorate its quality and durability.
anatomy of a jack
In a female jack, there are 3 pins that interest us: the Tip, the Ring and the Sleeve. Hence the name, jack TRS….
- The sleeve corresponds to the ground, our reference point.
- The Tip is the pin that carries the signal when you are in mono.
- And finally, the Ring which in the stereo case, carries the other audio channel.
When you forget to connect the ground, you just hear a big BZZZZEEEUWWEHHEUUUU. That is, an angry amp. And yes, you already experienced it when one of your cables died.
It is however the basis of an electronic circuit, the value of a signal depends on its reference! If you have not connected the ground from one circuit to another, they will have trouble to communicate because their reference levels are different!
In the case of jacks, the ground is also often used to shield our signal. The central core must be completely surrounded by the level 0, the ground that will allow the parasites to be captured and filtered. Like a shell that fights against disturbing waves!
solder a jack
- With the 3rd hand, I clamp the inside of the jack to hold it vertically
- I insert my wires into the legs of the jack from the inside to the outside
- I preheat the jack tab and the wire with one or two drops of tin
- When I see that the tin’s color has changed and that it is very bright, I can put the rest of the tin on to finish the soldering properly.
- I remove the tin and then the iron.
- I make sure that my wire does not start to oscillate. If so, I can hold it gently on the other side without moving. Indeed, it is absolutely necessary that it remains immobile to obtain a perfect weld.
- I’m cutting off the excess leg of the wire we just soldered.
pedal power supply
Without energy, an electronic circuit can never work!
This is often the most stupid mistake but at the same time the easiest to detect.
The power jack is already attached to the pedal enclosure. You will notice that there is a long leg and a short leg. The long one is for the +9V and the short one is for the ground.
Interesting little aside on the power supplies. A power supply imposes a voltage. While it is the circuit that sets the current consumption. Thus, a 9V pedal requires a 9V power supply. If the pedal consumes 20mA and the power supply can supply 500mA everything is fine! There will be 480mA left available to power something else. In any case, only 20mA will be consumed.
solder your DC jack
Using your nose pliers, place the red wire connected to your board in the long leg. Then do the same with the black wire in the shortest leg.
It may seem a little complicated to handle the soldering iron in a small space. But with a little practice it goes very well. Also be careful with your iron to be “vertical” enough to avoid burning a capacitor or any other components.