I have 9 of these running in a 10 port hub (el'cheapo off ebay) and running fine
but I have wired the hub to a 5V 30A power supply (also bought off ebay)
Note. I have cut the (red) power wire in the USB cable that connects from the hub to the PC. just in case it tried to pull power from it if the power supply fails.
http://i.imgur.com/PzhsC21.jpg http://i.imgur.com/BVZmmlL.jpgneat setup, the tip to power them up ingenious. I put your average hashing power to a calculator and it gives $10USD perday, Are you getting anywhere near that amount per day?
