Reply to Humming Sound from S4

I would like to figure out why there is a very loud humming sound coming from my speakers when I plug in the RCA cables into the S4,

The sound is much like interference and none of the settings within Traktor seem to make a difference.
Unplugging the laptop and running on battery does not work neither.
The sound comes through the speakers strictly when the S4 is plugged in and never with other devices.