Although I love my Jazz Bass, one of its typical problems was buzzing me off every now and then. Yes, I’m talking about the single coil hum, which is also known as the 60-cycle hum. In plain English; most jazz basses will produce a hum when you emphasize / solo one of the pickups. But when you turn the pickup volumes full simultaneously, the hum disappears.
Why Do Pickups Hum?
This happens due to the complex nature of magnets and electricity. In basic words; one of the pickups is wired clockwise, and the other one is wired counterclockwise. When you solo the bridge pickup, it exposes a polarity of +100 and produces a hum. When you solo the neck pickup, it exposes a polarity of -100 and produces a hum. When you turn them both on, +100 – 100 = 0, so they balance each other out and the hum disappears.
This is not the exact physical model of what happens, but rather a mathematical analogy to help you understand.
Precision basses don’t have this problem, because they have a split coil design. It has the single coil pickup split in two, and guess what? One of them is wired clockwise, while the other is wired counterclockwise. Therefore; in terms of hum, a precision bass is dead quiet because +100 – 100 = 0.
You can install noiseless pickups, but those will be stack-coil or split-coil magnets, which sound different than vintage single coils. Not necessarily bad, though; it is a taste thing.
There are ways to hide the single coil hum; though.
Some basses have phantom coils installed to balance out the hum of the single coil pickup.
If you use a noise gate pedal, it will mute the signal less than a certain dB. When you set up the threshold correctly, your hum will be muted when you stop playing.
EHX Hum Debugger is another pedal to cut the hum, which has a different approach: It completely mutes the frequency where the hum occurs. That modifies your tone too. Some people notice / mind that, some don’t.
Finally, you can turn down your guitar or balance your pickups until the song starts. The hum is audible during silence, but not as much in the mix.
Other Sources of Noise
Pedalboards can produce a lot of noise too. Check my corresponding article How To Get Rid of Pedalboard Noise .