Nady HE-1 60-Cycle Hum Eliminator
The HE-1 is a sure-fire bet for quick and easy removal of 60/120 cycle AC hum from your signal path. This two-channel mini-box is designed to eliminate hum caused by ground loops while also acting as a direct box capable of converting unbalanced signals to true balanced signals for long interference-free cable runs. Its passive design is easily portable with no AC sockets necessary. A couple of these are essential components in the tool bag of every musician or roadie.