Hum and Buzz: Isolate the Source

Start with the volume low

Turn the volume down before moving any cable. Disconnect all input sources from the receiver or amplifier. If the noise disappears, reconnect one source at a time until it returns.

If the hum remains with every input unplugged, the issue may be inside the component or its speaker wiring. Do not defeat the equipment's safety ground to make a hum disappear.

• Check for damaged or loosely connected audio cables.
• For a turntable, confirm its thin ground wire is connected to the amplifier's ground terminal if the manufacturer calls for one.
• Note whether the noise changes when the volume control is moved.

Document the pattern

Useful notes include whether the hum is in one speaker or both, whether it is present with no source connected, and whether it changes with the volume control. Those observations make a technician's diagnosis much faster.