Unique Product Solutions 3.5mm Stereo Audio Isolation Transformer 3.5mm Stereo Audio Isolation Transformer.Every installation technician has faced it or soon will - the dreaded humming from the speakers, a telltale sign of a ground loop. Ground loops are caused by voltage potential differences at the ground point on your equipment. Voltages in the range of microvolts up to millivolts or higher can cause ground loops. Ground loops occur when multiple audio/video components are powered from different outlets, most commonly, outlets that are tied to different circuitbreakers or even a different secondary from the power transformer.Ground loops manifest themselves in the form of speaker hum.Our isolation transformer easily connects into your audio/video system and breaks the ground path through cables between components. Start at the component last installed before the ground loop was discovered, and connect the isolation transformer at different ends of the audio/video cable until the ground loop is gone.