To learn how to fix ground loop hum, start by plugging all your audio gear into the same power outlet or power strip. A ground loop is a low, steady 50/60Hz hum caused by two pieces of gear being earthed through different paths, and consolidating the power is the simplest and safest fix. This guide covers that and the other proven solutions.
A ground loop happens when connected devices have more than one route to electrical ground, creating a small current that leaks into your audio signal as a constant hum. It’s different from hiss or buzz from a bad cable — ground loop hum is steady, low-pitched and usually changes when you plug or unplug devices.
Confirm it’s actually a ground loop
Before fixing anything, confirm the cause. Disconnect audio cables between devices one at a time. If the hum vanishes when you unplug, say, the cable between your computer and interface, the loop runs through that connection. If unplugging an audio cable kills the hum but the device still has power, you’ve found your loop. A true ground loop hum is constant and doesn’t change with the music. If it’s more of a hiss or only happens with one channel, see fixing a noisy or humming audio interface first.
How to fix ground loop hum: power first
The single most effective fix is to power everything from one point:
- Plug your interface, computer power supply, monitors and any outboard gear into the same outlet or one power strip. This gives everything a common ground reference.
- Avoid running gear from outlets on different circuits or different rooms.
- If a laptop only hums when its charger is plugged in, that’s a classic loop — try running on battery to confirm, then address the power path.
A quality power conditioner or distributor can make this tidy and is worth considering for larger setups, though it isn’t a magic cure by itself.
Use balanced connections
Balanced cables (XLR or TRS) reject hum that unbalanced cables (TS instrument leads, RCA) pass straight through. Wherever your gear supports it, use balanced connections — especially the run from your interface to your studio monitors. If your monitors hum, check you’re using balanced TRS or XLR cables rather than unbalanced ones; this often solves monitor-related loops. Our guide on positioning studio monitors pairs well once the noise is gone.
Break the loop on the audio side
When power consolidation isn’t enough, break the loop in the signal path:
- DI box with a ground-lift switch: the cleanest fix for instruments and long cable runs. The ground lift breaks the loop without touching mains safety.
- Isolation transformer / ground-loop isolator: an inline device that passes audio but blocks the ground current. Useful for stubborn loops between a computer and interface or between consumer gear.
Never defeat the earth pin on a mains plug with a “ground-lift” adapter or by cutting the earth wire. It may stop the hum, but it removes a vital safety ground and can be dangerous. Always break the loop on the audio side instead.
Other things that cause hum
- Cheap or unshielded cables — swap for shielded ones and keep them away from power leads.
- Dimmer switches, fridges and chargers on the same circuit injecting noise.
- Single-coil pickups picking up interference, which is a guitar issue, not a ground loop — see recording electric guitar.
For interference-style buzz on a mic line rather than a loop, see fixing microphone static and interference. More fixes are on the home studio setup hub.
Frequently asked questions
What does a ground loop hum sound like?
A low, steady electrical hum at mains frequency (50Hz in much of the world, 60Hz in North America) plus its harmonics. It’s constant, doesn’t follow the music, and often changes pitch or volume when you connect or disconnect devices.
Is it safe to use a ground-lift plug to stop the hum?
No. Lifting the mains earth removes a critical safety protection and can leave gear live in a fault. Always break the loop on the audio side using a DI box ground lift, an isolation transformer, balanced cables, or by consolidating power to one outlet.
Why does the hum start only when I plug in two devices together?
Each device on its own has a single ground path. Connecting them with an audio cable creates a second path, forming the loop. That’s why disconnecting one audio cable often kills the hum and tells you exactly where the loop runs.
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