6. Electronics

Guitar electronics can be intimidating. When replacing a tone pot or capacitor, you might thinking "OMG, just don't mess it up" i.e. you're suuuper careful that the connections look the same before and after. But really understanding how the electronics work is satisfying and can help you get the most out of your modifications.

As intimidating as guitar circuits may be, they are as simple as circuits come. I'd wager that any other electrical device you use in daily life is orders of magnitude more complex than your guitar (ok, lamps excluded). Your toaster? Those things are computers now, man. Because guitar electronics are largely unchanged from the 1950s, learning about how your guitar works can serve as a kind of general-purpose "Electronics 101" course. You'll learn about variable resistors, switches, capacitors, and inductors.

This first series of posts elegantly breaks down the basics of electric guitar wiring. The first post starts off with the most basic circuit—a pickup wired directly to the output jack—then each new section slowly adds more components while explaining how they work.

Guitar Wiring 101 - Basic Circuit Explanation of the most basic of guitar circuits: a single pickup wired directly into the output jack, effectively wiring the pickup straight into the amp.

Guitar Wiring 102 - Volume and Tone Adjustments Part 2 expands the circuit in 101 by adding a kill switch, replacing it with a volume pot, then adding a tone pot to the mix. Each step is explained in a easy-to-grasp way.

Guitar Wiring 103 - Pickup Selector Switches Part 3 adds another pickup and pickup selector switches, explaining the ins and outs of the switches used, and why the wiring schemes are the way they are. The post ends up with a Telecaster wiring scheme.

Guitar Wiring 104 - Les Paul and Strat Wiring Part 4 covers the wiring for both the Les Paul and Stratocaster. You got this because you read the other three posts!

(Wikipedia) Guitar Wiring Wikipedia is pretty solid for guitar tech info. This explains in more depth each of the electrical components in your guitar.

Soldering

Soldering is a must have skill. Fortunately it's easy and cheap.

How to Do It: Basic Soldering A great intro video; 2 million views cant be wrong.

From Schmo to Pro: Soldering 101 Detail on techniques and pitfalls. "First, what are we trying to accomplish by soldering? Soldering is the process of heating metal parts, applying flux and solder, to form a good electrical and mechanical connection between the parts."

Potentiometers

Those volume and tone knobs on your guitar? They are potentiometers, usually referred to as "pots" by guitar folks, and are basically variable resistors.

Which control pot to choose "In a nutshell: 250K control pots are the usual choice for single coil pickups. 500K control pots are the usual choice for humbuckers. These 'K' numbers are the resistance ratings (kOhms)."

Basic Electric Guitar Circuits 2: Pots & Tone Capacitors Goes into detail about how potentiometers work, including a bit on taper.

Capacitors

As you learned in the Guitar Wiring 102 article, capacitors or "caps" are used in the tone circuit to bleed off higher frequencies when you roll back the tone knob. Let's dig in a little deeper.

What is a Guitar Capacitor and how does it work? Capacitors specifically applied to guitar circuits. "A capacitor diverts the flow of lower frequencies and allows higher frequencies to pass through it. The cutoff point between the lower frequencies that are diverted and the higher frequencies that are allowed through depend on the value of the capacitor."

All About Capacitors A deeper dive into capacitors. "In the realm of passive components, capacitors are second only to resistors in ubiquity. [I]t's no surprise that capacitors are an integral part of audio circuits in general, and guitar effects specifically."

You can try several capacitors in quick succession with a breadboard, some alligator clips, and maybe a knob.

Change Your Caps, Change The World! Listen to side-by-side audio comparisons of different capacitor values in the same guitar

Crazy Tone Thing He shows you how to build a little apparatus to try out several caps with low effort. This post is the beginning of a three part series on experimenting with capacitors with videos comparing different material types and different capacitance values.

There is a lot of misleading information on the internet regarding capacitors, mostly that some vintage exotic-material $75 capacitor has "better tone" than another, more ubiquitous capacitor.

Do an Internet search for “Tone Capacitor” and you will find the most amazing mish-mash of fact, half-fact, lies and opinions. This type of capacitor is better than that one. This dielectric is brittle, and that one sounds smooth. This cap is better for rock and that one better for country. This one is more Fender-ish, and that one more boutique. Another hypefest just begging to be busted!

The Truth about Tone Capacitors They test frequency response in capacitors with the same value but 20 different different material types. Turns out, material type doesn't matter in guitar applications, only a capacitor's value. 💥

Switches for more tone options

Does that guitar you're looking at come with weird switches or buttons? Here's what they might do.

Coil splitting and tapping Coil split : using only one of the coils in a humbucker and disabling the other effectively turning it into a single coil. Coil tap : 'taps' into the coil at an earlier point in the winding thereby using less turns and reducing the output.

In and Out of Phase You can wire your pickups 'out of phase' for different tonal option. One pickup is wired backward to the other, which causes a cancellation of some frequencies, and a brighter, 'thinner' sound.

S-1 Switching A Fender feature to 'give you more tonal options'. Note that it has different functions on different guitars.

Shielding

Does your single-coil equipped guitar hum when you plug it in? You can probably get rid of most of that noise by shielding the electronics. Faraday cages are basically magic.

S.H.I.E.L.D.ing a guitar Explains what shielding is and when you should do it. "Touch the strings. ... If it buzzes less, or more likely, not at all, then your guitar wiring is fine and you need to shield it." Also, it's funny.

Shielding a Strat Guitar to Eliminate Hum A thorough how-to with a whooole bunch of pictures. Note that this guide uses aluminum foil held down with rubber cement. You can use the same techniques with adhesive copper tape sold at guitar supply shops.

Further Reading

Science of Electric Guitars and Guitar Electronics If you want to really dig in to your guitar electronics, this book is for you. It dives into the math and physics behind every circuit in your guitar, as well as circuits in common effects pedals. The first 82 pages contain an intro to music, physics, and electronics. 👍