Ah, here we are at Part 13. Maybe I should bow to superstition and call it Part 14. Yeah, right! Besides, the number 13 fits today’s subject; Electric Guitar Wiring.
When it comes to wiring up an electric guitar, the possibilities are as varied as the styles of music one can play. For this reason, I highly recommend studying the basic principals of electricity and how it applies to guitar wiring. You can follow a wiring schematic, but it really helps to understand what’s happening in the circuit you create.
Some wiring schematics can get very complicated.
Instead of boring you with the details, which could fill a massive book, let me give you a brief explanation of what happens when you pluck the strings of your guitar.
When the strings vibrate over the pickup, they excite the magnetic field contained within the pole pieces. This, in turn, motivates the flow of electrons in the coil surrounding the magnet. The flow continues through a circuit made up of wire, switches, potentiometers and capacitors, all of which control and shape the signal before it heads out to the amplifier. Sounds pretty simple, doesn’t it? However, it’s much more complicated than that.
The most important factors to understand are resistance and capacitance. Opposition the signal is resistance while capacitance refers to the ability of a component to store a portion of the signal. All of the components in your wiring scenario posses these two factors, which vary based on their individual designs. Some components are designed with resistance as the main influence while others are geared more toward capacitance. For example, a potentiometer is big, variable resistor while a capacitor is designed to soak up some of the signal.
To some, it may seem like resistance and capacitance are a bad thing–after all, don’t we want a strong signal to travel from the pickup straight to the amp? Sure, but then you wouldn’t be able to adjust the volume and tone at your guitar. When you turn down the volume knob, you’re actually increasing resistance which weakens the signal. And when you turn the tone knob, resistance increases and channels the signal into a capacitor, which absorbs the treble frequencies.
It would be easy to wire a guitar if there were only one type of potentiometer and capacitor, but that’s far from the case. There are hundreds to choose from, each with their own unique specs. That’s why it’s so important to learn what the values mean.
Sure you could follow a schematic without knowing the whys, but I’ve come across more than a few that simply don’t work. And if you’re on a budget–who isn’t these days–you’ll save yourself both time an money if you can make the right decisions based on a thorough understanding of how the values affect performance. Also, don’t assume a wiring schematic you found will do the trick. Most scenarios are based on personal preference.What worked for one person may not work for you. But if you don’t know this, you won’t find out until you’ve closed the control cavity and play through an amp.
Now, lets talk about soldering for a minute.
You can have a good schematic, wire and components, but still screw it all up with a bad soldering job. Use solder specifically for wiring, not the stuff plumbers use. A 15 to 30 watt soldering iron works fine for most tasks, but you may want a higher wattage when soldering several wires to the back of a potentiometer. Whatever you use, make sure your solder joints are SCS. Small, clean and shiny. If they’re splattered and dull, the electrons won’t flow through.
Follow a good schematic and do most of the work outside the guitar. I use a cardboard box lid to hold the controls while I work.
Before you start soldering, take a good look at your schematic and decide how much of the work can be done outside of the guitar’s control cavity. Try and do as much of the soldering as possible before you install the components. And lastly, DON”T FORGET TO RUN A GROUND WIRE TO THE BRIDGE! If you forget to do this, you’ll be reminded with a jolt the first time you touch an electrical component, such as a microphone, that isn’t properly grounded. With a tune-o-matic, the ground wire is fed into one of the post holes. With a tremolo bridge, there should be a provision to connect the ground to the bridge block. Regardless of the bridge type, the other end of the ground should be soldered to the back of a potentiometer along with the pickup grounds.
That’s it for Part 13. In Part 14, I’ll discuss applying finishes. Stay tuned!