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That 12V, 10A PSU should give you plenty of power, 120watts. That's 2.4 amps per port. I would not use an old cctv transformer its output will not be as clean as a switching power supply. The bad part is that hub has 5 DC to DC step down converters in it, one for every two ports and they are only rated for 5 amps or less each so even with a bigger external power supply you may overheat the Dc to Dc converters inside if you try to pump too much current thru the USB ports.
It does I'm just trying to find a solution where I dont need to use 2 or 3 psu's 1 for the hub, 1 for the pi, 1 for the fans. might just rip apart a 12v 2a link that to a 12v usb charger and the fans and mount all of it in a box with an extra fan and an iec socket linked to the 2 12v psu's. at least then I'd only use one socket and tidy it up a bit.

as you can see currently the pi's powered by the extension strip the 2 fans are linked to a 12v psu on the left and the hubs psu is behind. I'm far from the best maker but fun project and its starting to take shape
