Usually single-coil pickups collecting interference, and it changes as you turn. If the hum stops when you touch the strings, the guitar’s earthing is working and the noise is being picked up rather than generated.
Rule out the room first
Screens, dimmer switches, chargers and fluorescent lights all radiate. Turn and walk around the room with the guitar plugged in: if the hum changes with your position, it is the room, not the guitar.
Then the cable
An unbalanced instrument cable picks up more interference the longer it is. Three to six meters is the practical range; a coiled ten-meter lead behind a desk is an aerial.
Then the amplifier
A hum that is present with nothing plugged into the amplifier is the amplifier’s own, and no guitar change will alter it.
Check your own manual before you plug anything in. Voltage, polarity and current draw differ from model to model, and the manufacturer’s figures take precedence over anything written here. A supply of the wrong polarity can damage a pedal in seconds, phantom power is safe for most microphones but not for every one, and the required voltage is printed next to the socket or stated in the manual — not inferred from a connector that happens to fit.
The questions players ask
Why does touching the strings make it quieter?
Your body becomes part of the earth path and shields the pickups. It is normal on single-coil guitars and is not a fault.
Do humbuckers fix it?
Largely — that is what the name describes. Two coils wound in opposite directions cancel the induced hum, which is why humbucker guitars are quieter under lights and near screens.
Last reviewed 2026-08-18