Greetings, I have 2 of the 4 port USB hubs. I've had them for quite some time and they have served me well however if I plug a hard drive in a USB enclosure into them there's apparently not enough power supplied from my USB port to power the drive. I have been shopping around for a powered USB/media hub as I have several devices that I use and would like to be able to have them all connected to my pc at the same time but the hard drive being one of them isn't an option. I found the same one I have only with a power supply and when I looked at mine, they have the plug for a power supply already so all I need is a power supply that is compatible with them. Do you sell, or can you recommend the particular power supply that I need for them?