Ebtech HE2XLR Hum Eliminator  2 Channels 
2 Channels with XLR and 1/4-inch jacks Item #: EBT HEXLR 

The Ebtech Hum Eliminator XLR breaks the ground loops that cause AC hum, quickly and easily.
Just plug the HE-2 XLR in between the offending pieces of equipment and you’re done. No signal degradation, no noise gates, no dangerous ground lifts, no hum! Also converts balanced and unbalanced signals. This 2 channel Hum Eliminator equipped with 1/4 inch ins/outs AND XLR ins/outs. The Hum Eliminator also incorporates a passive design, which means no power required.

Hum Eliminator
Almost all AC hum (60Hz in the US) is caused by ground loops. These groundloops act like radio antennae picking up hum and noise. The Hum Eliminator completely eliminares this breaking the goundloops, making it impossible for the signal lines to pick up the AC hum and noise in the first place.

Just plug the Hum Eliminator into the signal lines between offending pieces of equipment and you're done. It's that easy. No buss, no hum, NO signal degradation, No filtering, No noise gates, No dangerous ground lifts.