Jack Sockets

More important than any other component is the jack socket. Now that's no fun! Well yes, that's true, but if you can't connect in to your nice fancy boutique pedal with a load of clever circuitry and a pretty enclosure, it won't do a damn thing!

Jack plugs and sockets are pretty unremarkable. They just provide a mechanism to pass the audio signal into the pedal circuitry. The plug/socket combos we're interested in are \(6.35mm\) (\({1 \over 4} inch\)) in diameter. They come in two flavours: mono (also known as 2-pole or tip-sleeve), and stereo (3-pole or tip-ring-sleeve). You might already know that mono means that our audio signal has a single channel (if you listened to it through a pair of headphones, both ears would be hearing the same single track), and stereo means there are two channels (each ear would hear its own track). Most standard guitar cables and connecters are mono and so we'll focus on this variety. Note: there are some interesting ways to make use of a stereo socket, even with a mono plug!

The image below illustrates the difference between a 2-pole and 3-pole jack. These names come from the number of conductors on the jack plug, where each conductor is separated by a slice of insulation (the black lines on the plug). The Tip and the Ring conductors carry the audio signal through our effects loop - they are the 'hot' connections. The Sleeve is connected to ground in each circuit. If you imagine we had an AC signal generator, we could connect the positive terminal to the Tip and the negative terminal to the Sleeve of a mono jack-socket, and then plug our lead in and feed this signal out to some other circuit.

We'll look at how to wire a jack-socket up in our first pedal circuit.

Wires

Again, a little dull... sorry. We'll get to the actual components soon enough. But of course, without wires, you're not going to get very far, so we should touch on them quickly.

In the world of electronics, there really are a bunch of different types of wires. Luckily for our application, we can focus on just one or two. Wires can either be single-core or multi-core. In both of these varieties, the cores can contain solid or stranded conductors. We'll be working with single-core wires with a solid conductor core.

We don't need multi-core wire as we're just passing one signal around a small circuit. We're using a solid conductor core becuase it's far easier to use with our prototyping boards (it's the difference between trying to thread an old, frayed shoelace; or a brand new one with the aglet still intact). Stranded core wires are much more flexible, and so less likely to fracture, but this isn't an application that demands flexibility so we can deal with a more rigid wire.

The diameter of the conductor and the total diameter of the wire (including insulation) are variable, and you can find out more about the American Wire Gauge (AWG) standard here. We're most interested in AWG 20 to AWG 24 - these fit snugly into the holes in our prototyping boards, and the current ratings are way higher than we will need.

Resistors

Wow! Actual components! Alright calm down, they're just resistors... That said, they are perhaps the most common components in all electrical applications. Every circuit that we look at will contain resistors (or potentiometers - a type of resistor).

A quick refresher: resistors resist the flow of current. Voltage is the force that 'pushes' current around our circuits. If we impose several restrictions on this flow in the form of resistors, more of that pushing force is going to be 'used up' to overcome the 'tighter' restrictions - this is what is called the 'voltage drop', or the voltage between the legs of a component. You might be familiar with Ohm's Law, \(V=I \times R\), which simply states that the voltage difference, \(V\) across the two legs of a resistor is directly proportional to the current flow \(I\) through the resistor, with the resistance \(R\) being the constant of proportionality.

Resistors convert electrical energy to heat. This might seem undesirable, but we can use resistors as tools to manipulate our signal in some really useful ways. We'll see resistors used for several purposes - some of which will be covered in detail on the 'Important Concepts' page. In a typical circuit, we might see resistors used as voltage dividers, pull-down resistors, current-limiting resistors or frequency filters.

Resistors come in all sorts of sizes (see the below resistor colour chart). This is where we start seeing the opportunity for experimentation. With each of the circuits we look at, it's worth trying to swap some resistors out for different sizes, and seeing what affect that has on the output.

Potentiometers

A potentiometer is a variable resistor - you might hear them called pots for short. They should be quite familiar to you - those knobs on your guitar that control volume and tone are potentiometers! You might also hear them called variable resistors, because that's really what they are.

A potentiometer is a resistor with three legs, and has a dial to control the resistance between each of the legs. The potentiometers symbol paints the picture quite nicely:

Legs 1 and 3 of the potentiometer in this symbol are just like a normal resistor. Leg 2 is connected to a wiper that can move across the resistor. This means that the resistance is split in two - there's one resistance between legs 1 and 2, and another between legs 2 and 3. So if we had a \(250k\Omega\) potentiometer, and the middle leg was \({1 \over 4}\) of the way from leg 1, we could represent the circuit using two separate resistors, like this:

Conveniently, this is just a potential divider, which is a common and useful bit of circuitry.

Capacitors

Capacitors are another important component, and as we'll see in important concepts, they can have many functions in our circuits.

Switches

Primarily used to turn an effect on or off, switches are handy components.

Diodes

Here come the semiconductors! As we start looking at some more complicated designs, like overdives, diodes will start to become more important.

Transistors

Operational Amplifiers

Breadboard

Breadboard is a really useful piece of kit. It's a prototyping board that allows you to quickly commit a design to hardware, but without any tricky soldering. Breadboard works very simply - it's a plastic board full of holes, with strips of conducting material under the holes. You just slip your components in the holes and you're good to go! This makes it very easy to build up and modify.

Stripboard

Wire Strippers

This is where things start getting more optional.

To fit your wires into breadboard/stripboard, and to have the wires function as they should, you'll need to strip the insulation off the ends to expose the conductor underneath. Wire strippers also allow you to cut lengths of wire that are more managable than \(10m\) coils... That's really all there is to it!

They really do make your life a lot easier, so depending on your plans, it might be worth splashing out ~£15-£30 on a decent set - something like this should do the trick nicely!

Some soldering kits come with little wire stripping tools, so if you think this might do the job, you might not need a larger set too.

Soldering Equipment

Multimeter

A multimeter is a useful tool for anyone working on electronics in any capacity. A multimeter is by no means necessary, but it can make troubleshooting a lot simpler - you can take measurements across your circuits, determine the polarity or sizes of components, that kind of thing.

Maker Board