Hum

[MarkHolbrook]

Hi, I had to return my beloved wavedrum global because a channel dropped out and the cheap plastic counterlever for the head pressure sensor height wouldn't adjust properly. Korg replaced the unit which is great but the replacement has a pick up hum when my hand approaches the skin. Weirdly this is only on some tones. All that is connected at the moment is the power supply and headphones. Any ideas?