so I just turned on my micro terror and was getting this crazy hum. Like the hum you get when you crank the gain and volume to ten, except that I had gain around 4 and volume at 3 . As I started unplugging pedals and checking cables I thought I would try unplugging my vox ac15 (it wasn't powered on just plugged in). Instantly the humming disappeared. Can any of you guys tell me why this would happen?