Reply To: H9 humBy owen33 / June 1, 2014 Home › Forums › Products › Stompboxes › H9 hum › Reply To: H9 hum June 1, 2014 at 2:13 am #126029 owen33Member Using the supplied eventide wall wart. That is the only thing plugged in. No guitar or amp. Its something internally in the pedal humming. Like a transformer would hum.