[javierAizpuru]

Hi! , just bought the apogee One and every time i connect it to the power supply for using it with my ipad i get a hum sound ( listen to it in the link below), the hum only comes up when the one is connect to the power supply (if i connect it to my macbook using the usb for powering it the hum sound doesn't comes up), also the sound can be hear in my headphones and if i grab the ONE and get it near a wall or the floor the hum gets louder. 
 
is a ground loop or the power supply cable is damaged?
 
SORRY FOR MY ENGLISH, IS NOT MY NATIVE LANGUAGE. HOPE YOU UNDERSTAND EVERYTHING I WROTE.
 
Hum sound:
 
https://dl.dropboxusercontent.com/u/51422472/One%20hum.mp3