To rid the hum / hard drive noise, I have this Hama ordered NF-noise filter, ok this works until the cable / plug to be moved, it crackles equal and the sound on one side is gone ... until you wobble back to the connectors (as described below).
Because I wanted to use this filter for the recordings this is not for me to use, because the noise landed directly on the recording ... therefore returned and ordered by Behringer, may cost twice as much but works fine.