At the end of the last Guitar Wiring article, we knew how to wire a Tele, a Les Paul and a Strat in their usual ways. Most stock guitar wiring is a variation on these three standard ways of wiring a guitar.
Using the knowledge contained in the previous four parts, we can now look at modifying our wiring schemes to achieve non-standard sounds. The first modification most people do is to replace one or more of the potentiometers with a push/pull pot. This is a pot that works in the same way as normal when you turn it, but also has a double-pole, double-throw (DPDT) switch attached. The switch is moved into one of its two possible positions by pulling the pot’s knob out and away from the guitar, or pushing it back in again.
The potentiometer and the switch are completely separate electrically, and there is no need for the functions of the two controls to be related in any way.
A push/pull pot looks like this:
From the outside of the guitar, it looks like nothing has changed – and replacing an existing pot with one of these requires no new holes or other modifications to the guitar. You can see in the photo that there are six contacts under the pot in addition to the usual three. These six contacts are for the DPDT switch, and are connected together internally in the two positions as shown here:
As you can see, we have two separate poles to work with. Our first mod will use this switch in the simplest way possible, using only two of the contacts.
In a Strat that’s wired in the normal way with a 5-way switch, you can have the bridge, middle or neck pickup on their own, or a combination of the middle pickup with one of the other two pickups. However, you can’t have the neck and bridge pickups together, or all three pickups at the same time.
A popular Strat modification is to add a push/pull pot which, when pulled out, adds the neck pickup to the currently-active pickup selection. This would mean that when you select the bridge-only position on the 5-way, and then pull out the pot, you will have neck and bridge together. And to get all three pickups simultaneously, you would select bridge and middle on the 5-way, and then add the neck pickup using the switch. This increases our total number of pickup combinations to seven.
The diagram below is part of the standard Strat wiring diagram from the previous article. The tone pots and most of the ground wires have been removed so that we can focus on what’s being added to the wiring. The new wires are shown in purple.
You can see that we’re taking a wire connected to the neck’s hot output and a wire connected to the input of the volume control, and ensuring that they are connected together when the pot is pulled outwards. This overrides the neck pickup’s connections in the 5-way switch and connects it straight in with whatever else is selected.
Of course, if you prefer, you could do this modification using the bridge pickup instead. I’m sure you can work out how you would wire that!
While in this instance we used a push/pull pot to achieve our aim, it’s just a type of switch. If we wanted to use a mini-toggle switch, perhaps installed between the volume and first tone control, it wouldn’t be a problem. The most common type of mini toggle switch used in guitar wiring is also a DPDT switch, with the same six contacts, like this:
To use this switch, our wiring diagram wouldn’t change at all, other than the fact that the switch wouldn’t be directly joined to the volume control any more.
There are other types of mini-toggle switch, which have three positions instead of just two. And we only used two of the contacts on this switch for this mod. Aren’t there fancier things we could be doing? Yes there are. And we’ll move on to those in due course, but before we do, we’re going to need to de-mystify four-conductor humbuckers. That’s what we’ll be doing in the next article.