Reason being is I'd like to get an exchange before time runs out if it isn't.
When charging through usb (red light comes on), I'll get random crackling, static, sometimes a faint hum in the background. Sometimes a little hiss, as soon as the usb cable is unplugged it's back to normal in an instant. I have not experienced any interference or problems at all as long as it's not charging while turned on, and can use it for hours.
Source: Realtek ALC889A
This has been tried at mutliple volume levels including the lowest volume on the amp.