Its just that a couple of reviews I've seen have powered the Modi from the iFi iUSB unit and say it's better. The only problem is that the iUSB costs twice as much as the Modi.
Maybe a powered hub is the answer, but I was thinking of maybe a small regulated 5volt PSU feeding it power through a spliced cable, or maybe via a through connection on the PSU where it takes in the USB signal from the laptop, but the output to the dac uses the regulated and clean 5volt supply.
Its only a thought, hopefully if I keep taking my tablets this madness will subside.
BTW I thought that the ferrite beads only helped with RFI and wouldn't do much for other noise.