I just recently got my MiBox 4k. Everything works fine, except there's this faint, but clearly audible electric sound coming from inside of the device. Kind of sounds like a hiss from a bad usb charger. This is annoying when everything else at night in the room is quiet but I can clearly hear the box working (even in "standby" mode). I would imagine this device shouldn't be making any noises due to lack of moving parts, just like with the mobile phones. So is this normal or did I get a faulty unit? Thanks in advance guys.