They list the psu as
- Comes with 100~240V US plug AC power adapter
- Output: 400mA
1 asic need 500mA or .5 amp.
I use Roswell RUB-500 10 port hubs, they have a 4 amp psu, enough for 8 miners. I run 7 to have a .5 amp headroom.
I've seen 6 of the rhb500's connected to a single rhb500 and the single connected to a RPi, runs 64 miners with no problems. The single hub also held 4 miners.
I have more hubs and miners on the way, good way to waste money.