m scaler needs usb power for usb detection as I know. though usb input is galvenically isolated from inside. still if someone wants to feed cleaner usb power, ifi idefender is best choice. it cuts the usb source dirty power and you can replace it with a 5v battery power or ifi's own ipower. ifi claims it to be better than battery but imho no power can be better than battery. so a 4xAA NiMH battery pack with usb pin can be a good option to replace is usb power via ifi idefender.