The Nady HE-1 eliminates AC hum (60Hz/120Hz buzz) easily with up to 20dB of attenuation. The HE-1 converts automatically back and forth between balanced and unbalanced lines at either end, and can be used as direct box which converts signals from unbalanced to true balanced. Breaks grounds loops safely, while leaving all signal grounds intact. Dual Channel I/O with 1/4" TRS 'smart' auto-sensing jacks. Completely passive design with audiophile quality components assures the best possible noise-free and distortion-free performance.