Netzbrummen
Netzbrummen is a term used in German-language electronics to describe an audible or measurable hum and related noise that originates from the electrical power network (Netzspannung) and propagates into devices connected to it. The phenomenon is common in consumer audio, home theater, and laboratory equipment, where it can degrade signal integrity and user experience.
Causes include ground loops created when multiple devices are connected to different outlets or grounding paths,
Effects vary from a subtle hum in speakers and headphones to measurable noise in measurement instruments and
Remedies include using a single power outlet for devices sharing a signal path, installing isolation transformers
Etymology: Netz (network or mains) and brummen (to hum). Historically, the term has been used in German