I also found a few options in my Kemper to reduce the hum, besides the obvious noise gate check the following:
1. System > Page 1/18 > Line Frequency: should be set to 50hz (fixed or auto) for Europe (220 volts) or 60hz (fixed or auto) for USA (110 volts)
2. Input > Clean Sens (i set this to -7.1dB)
3. Input > Distortion Sens (i set this to -7.1db)
These help to tame the hum a bit without much tone sacrifice which naturally happens when you crank up the Noise Gate.
i just moved into a new building in Brooklyn and the hum is driving crazy ... i bought power conditioner and hum x and pretty much all of these did absolutely nothing to fix my hum problem, just a waste of money. I highly recommend before you rip out all the walls and rewire the entire house get this "Vox amPlug 2 AC30 Headphone Guitar Amp" ... basically it runs on battery and can tell if you our problem is purely EMI in the air and not grounding/wire/or all the other non-sense that you can spend thousands of dollars on identifying. The only solution i found so far is getting Lace Sensor Holy Grail pickups ... they are the only pups that greatly reduced hum for me. Still looking for solutions...
