Block low-level DC voltage sitting on your AC power line that causes the power transformer to hum or buzz.
This type of mechanical transformer hum may be caused if other devices on your power line, or devices on nearby power lines, use AC power asymmetrically. This quite common low level DC tends to make toroid power transformers hum and overload. The effect is often seen in products with toroid transformers, but it’s not limited to just toroids; thus, the non-toroid transformers can also hum depending on the level of DC voltage on the AC line.
The HumDinger also has a transient surge absorber on its incoming power circuit that will somewhat reduce turn-on surge currents in your equipment, prolonging their power switch and electronic component life.
Reduce the hum you hear out of the speakers. This type of hum is often generated in the audio circuits, or by grounding issues (normally between components). The HumDinger only reduces transformer mechanical hum caused by DC voltage on the AC line.
Provide any RFI filtering. Provide line over-voltage, surge, or lightening protection. You need a dedicated suppressor for that, the simplest being an AC outlet strip designed for computer AC line protection. You can use one of these either ahead of or after the HumDinger if you desire.
Cure hum caused by a defective noisy power transformer. If the transformer has a loose core that hums the HumDinger may reduce the hum slightly, but will not eliminate it.