The HE-8 Hum Eliminator from Ebtech is an eight channel rack mount unit, designed to eliminate 60 cycle hum caused by ground loops. It is also designed to convert unbalanced lines to true balanced lines, since unbalanced lines are more susceptible to picking up electrical noise and RF interference.
The HE-8 Hum Eliminator prevents ground loop antennae from forming and picking up AC hum. AC hum and noise are almost always caused by a loop antenna effect across signal lines between two or more pieces of gear, or by long unbalanced cables picking up noise. Loop antennae are basically a type of radio antenna, which tend to pick up the 60Hz (and harmonics) AC signal being broadcast by a building's electrical current. These loop antennae are closed circuits usually along the ground wires and hence are commonly called ground loops.
Unbalanced signals are more susceptible to picking up electrical noise and RF interference than balanced signals are. The longer the unbalanced cable, the greater the chance of a problem. The
HE-8 Hum Eliminator is one of the most cost-effective ways to convert between unbalanced signals and true balanced signals.