DanEcho Delay Pedal: Knocking Sound

Anybody ever get a knocking sound with the DanEcho delay pedal, when you're not playing? Here's the scenario:

I'm using a Megatone Wezo 45, amp cable is plugged into the out port of the Dan-Echo, mic cable plugged into the in port. Turn on the Wezo, wait 30 seconds, turn standby off (green light's on now). And knock-knock-knock-knock......... I have not even pressed the pedal delay on, and the mic is not near anything to pick up sound anyway. When I try to turn on the delay pedal it won't go on. The amp is plugged into a surge protector. I do have a long cable from amp to Dan-Echo and then another long cable from Dan-Echo to mic. I understand they work like an antenna, so could it picking up something?

I will call Den-Electro tomorrow. Wondered if anyone had this experience.

Anne Marie