Home › Forums › Products › Stompboxes › H9 hum › Reply To: H9 hum June 2, 2014 at 6:12 pm #136753 owen33 No, just the power plug, no usb, no 1/4 in plugs to guitar or amp, nothing else plugged in to the power strip. On power up it's a loud hum followed by a click and then a less noticeable hum.
