Ground Loop
Definition
An unwanted electrical condition that occurs when multiple pieces of equipment are connected to different ground points, creating a loop through which current flows and produces an audible 50/60Hz hum (depending on AC frequency). Ground loops are one of the most common sources of noise in home and project studios.
Context
Ground loop hum is a frequent troubleshooting topic in newbie-questions. The classic symptom is a constant low-frequency hum or buzz that persists regardless of gain settings.
Common Fixes
- Plug all audio gear into the same power strip/outlet — eliminates potential differences between ground points
- Use a DI box with ground lift — breaks the ground loop path (see DI Box)
- Check cable connections — damaged or poorly shielded cables exacerbate the problem
- Isolate the source — disconnect gear one piece at a time to identify which connection creates the loop
- Use balanced cables (XLR/TRS) — balanced connections reject common-mode noise including ground loop artifacts
What NOT to Do
- Never use a ground lift adapter (“cheater plug”) on your main power — this removes the safety ground and creates an electrocution hazard
- Don’t assume it’s a software issue — ground loops are always electrical/physical