A stompbox's hardware

Let's see deeper into every part we saw about in the last post.

1. The in and out plugs. I will be calling them "sockets" from now on, since "plug" is better used describing the male side (the jack).

This is the first and the last thing your signal hits on its way through the pedal. There are all kinds of sockets around, and all kinds of qualities. There are some different characteristics on them, let's see a few.

All these are mono sockets, the type that is used widely in all kinds of effects. You can see the difference between the cheap and the Neutrik one. The first is made of lesser materials and it doesn't seem very sturdy at all. The second is ready for heavy duty and will take you far more along the road. You'll have to go to extreme lengths to say there is a sound difference between those two though. The two connections shown in third socket are the signal "TIP" and the ground "SLEEVE". If those connections to the socket are tight, you are good to go. And that's mostly what the cheap socket fails at, as the connection softens due to its light build and the plug starts dancing around.

Here are some different kinds of sockets we often see.

The "closed" type shown on the left has a sturdy plastic body and very nice contact system. The plug... well, plugs better. This type also has a switching system, let's say that it can "break" or "create" a connection when you plug in. These take a lot more space than the open type, and also they are designed so that they don't "ground" the box. 

2.The infamous Footswitch (and other switches!)

We are flipping switches all day long, and if you are into sound stuff, you are very well acquainted with the "toggle switch". Now, I'll have to briefly explain how switches work. 

Here are some standard toggle switches, you usually see the upper part of them. Switches are categorized like this: (1) Single Pole Double Throw, which means that there is one column, and the middle pin can connect to either of the other pins. (2) Double Pole Double Throw, two columns with 3 pins each. (3) 3ple Pole Double Throw, three columns, 3 pins each.

Ok, here is what happening into a DPDT switch.

Two columns, 3 pins each. The center pins (2&5) are connected either up (to 1&4) or down (to 3&6).

Let's see what we need multiple columns for. 

Here is our pedal's main signal connections.

Here the signal enters through the socket, goes to switch 1 AND is also linked to lug 6. So when the toggle is on the "down" position, 2 connects to 3 (nothing there), and 5 connects to 6. As we see in the signal path, signal travels from 6 to 5 and then to the output socket. Our signal did a little trip through the switch and came out unaltered, also known as "true bypass". 

Now if we flip the switch.

Now the switch is in the "up" position. Connects 1 to 2, which sends the signal in the effect board. The signal comes out to lug 4 which connects to 5 and then to the output. That is effected signal of course. Notice that lug 6 is now not connected anywhere so there is no problem with the signal going there through the link.

That above is the main way we wire a stompbox, but we use a 3pdt switch because we need one extra column to control the indicator LED.  There are two or three different ways to wire a bypass switch, you can easily find them online.

All the switches we saw till now are "latching" ones. That means they lock in position after you toggle/stomp them. There is a different kind of switch called "momentary". The momentary switch can have the same patterns (dpdt etc) but they always rest in one position and connect to the other one only while they are pressed. You will see those in some functions like tap tempo. The most usual type is this one.

That is a momentary SPST switch. Single pole, single throw. The two lugs are not connected until you step on it, so you can send a single signal to the circuit when you "tap" it. Used mainly for tap tempo and for relay bypass switching. I'll explain more about bypass methods later on.

3. Power supply.

There is really not much to tell about the socket itself, it comes in 2-3 different shapes, which doesn't really make a difference to the user. The builder will usually choose what is best for the box (shape, size etc).

We'll talk about power later on. For now, I'll say that there is no difference between power sockets, even their quality doesn't differ that much.

4.Potentiometers 

As I said before, pots are actually part of the circuit. They are variable resistors that change current flow around the effect. They come in many sizes and shapes but they all have the same function.

Let's see how volume pots are usually used.

We'll use a 100KiloOhm (100K) pot.

 Let me explain that picture. There are 3 lugs on the pot, we see where they stand beneath the knob. Looking inside the enclosure we see the back of the pot, where the lugs are reversed. Now, for the wiring.

Lug 3 connects directly to the circuit output. It is the full signal output from the effect.

Lug 2 is connected to the switch and goes to the output socket of the pedal.

So, if the pot is turned all the way up, it connects 2 and 3 with zero resistance between them. That's the way you get full volume from your pedal.

Lug 1 is connected to ground. 

If we turn the knob all the way down, 1 and 2 connect, leaving the main output grounded. That means there is no sound at all (ideally).

With the knob at 12 o'clock, we get 50% of the signal to our output. *

100K means that in any given position there will be a total of 100Kohms resistance between lug 2 and the other two.

* There is another attribute of the pot among with the resistance. We get pots that have a different resistance sweep while turning. There are Logarithmic (type A), Linear (B), and Reverse Logarithmic (C). 

I'll lend a picture from a very nice article about pots, for anyone interested further, Secret life of pots

Ok, that above is the resistance between lug 2 and 1 while turning the knob up. This also happens at the same time across lug 2 and 3 but mirrored.
Let's see what we'll get by setting each type to the middle position.

So with each type we can achieve more control in certain areas across the sweep.
A, B and.... C is the usual type of pot we come across. There are other custom-made pots which you can't commercially buy. That goes mostly for resistance values, and rarely for sweep type.

So we have something that won't actually change the sound of a clone, but can change the setting you need to dial in to achieve it.
E.g. if some distortion uses a 52Kohm pot, you'll need to look in special places to get it. Mostly you'll use the easy-to-find 50K instead. That way our pot has to be a little off to have the same result as the original.

Ok, I think that's long enough for now. We'll see about circuits and components next time.