Some customers have reported hearing a hum when they touch the knobs on their MiCO. This is due to a ground loop being created. Unfortunatley this cannot be solved with the earthing screw on the rear of the device. However, this issue can be easily resolved using a small piece of thin gauge copper wire. Simply wrap the thin copper wire in the gap where the shaft meets the threaded housing of the pot and clamp down the tail of the wire under the screw that holds the MiCOs knob onto the shaft. Do this on all pots and the hum is completely eliminated. Below is a photo showing the repair.