Independently, neither hum noticeably. With the Boomerang looper in the chain after the entire pedal board, there's a noticeable hum. New cables, LiveWire and Mogamis. The back of the Boomerang says its 9-10vAC. My pedalboard consists of a few Boss pedals, Tim, Zen, this and that, which I believe are all DC. Would the AC Boomerang and DC pedalboard cause this? HELP!