Networking
Ground Loop
A hum or buzz caused by two pieces of connected equipment sitting at slightly different ground potentials, creating current flow through the signal path.
The classic symptom is 60 Hz hum in audio, or rolling bars in analog video, that appears only when two subsystems are connected — a rack and a projector on separate circuits, say. Sound is the messenger; the actual problem is electrical.
The correct fixes are electrical: feed connected AV equipment from a common circuit and panel, bond the rack properly, and where paths genuinely must cross grounds, break the loop with a transformer isolator or fibre. Lifting a safety ground pin fixes the hum, violates code, and is dangerous.
Related terms
- Surge Protection
- Devices that clamp voltage transients from lightning, utility switching, and large motor loads before they reach connected equipment.
- Grounding and Bonding
- The code-required practice of connecting equipment, racks, cable shields, and telecom backbones to a common electrical reference so fault current has a safe path.
- Impedance
- The AC resistance a loudspeaker presents to an amplifier, measured in ohms; it determines how much power the amplifier delivers and how many speakers can safely share a channel.
More Networking terms
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