Driveway wrote:
Einstein9, they are both single drives. The Quadra has 4 outputs: USB3, eSATA, and 2 x Firewire 800, and the other one just 1 x USB3.
Logic would suggest the Quadra is 3A, but I take pclab's point. I am just being ultra-cautious.
Most normal 3.5" drive external drives comes with 1.5A, If 2 drives (USB/Firewire...etc they use 2A & 3A)
If you use the 2A for the single drive it should work even the 3A will work
Then When can i use the 3A on a 2A storage? Well if your storage has for example USB connection which allows connecting EXTRA drives to the unit,
of course the extra drive needs power which tells you here that your Source (3A) should be enough to handle both
hope its clear here
fzabkar is an expert here for electronics troubleshooting & diagnose.