Uniti Core USB current capacity

Hello All!
I’m configuring a new backup drive for my Core and am considering using USB power instead of an LPS. Does anyone happen to know the maximum current capacity the Core can pass through its USB?
The drive is Samsung Evo 870 2 TB, 2.5 watts typical draw but claims up to 4.5 watts burst mode. I’m thinking 0.5 amps would cover the typical usage but concerned if the drive would require more. Maybe it’s better just to use a power supply? Any advise would be appreciated!

I use an 860 without problems but I haven’t checked the figures.

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This should work fine as I use a Seagate 2 tb Usb as a backup for my Core. No extra power supply needed.

My 6 tb, which has a larger form factor, used to be inside the Core but has now has been put in a case and converted to usb for multiple use. This needs more power than the usb ports on the Core provide and so I use a separate power supply (walwart) for this.

I tried to get this information from NAIM a while back for my HDX. Couldn’t get a definitive answer. Consensus on this forum was (based on nothing) 500mA. That translates to 2.5W (ie the standard USB spec). I ended up using a separate power supply, just in case.

I ended up doing the same thing. The small case I have for the drive came with a 2 amp USB/110V adapter so it made sense just to plug in. Thanks for the response!

You don’t need to worry about this with the UnitiCore. It is intended that its USB ports should be able to power normal USB hard disc and SSD drives and I have used all sorts of things as backup drives with no problems. The Samsung 870 EVO is fine.

The situation was completely different with HDX and Unitiserve where the USB ports were intended only for USB sticks and USB drives generally don’t work with those products.


Thanks David-
Do you know if there is a rated capacity on this bus just for future reference? I’ve heard of some devices having a capacity going up to 5 amps but USB spec of course would be much less. Just wondering what the options would be.

I don’t know what the rating is, but I have closely followed stuff relating to Core since it’s original release, including doing lots of firmware beta testing and I don’t recall anyone ever running into a problem where there wasn’t enough power from a USB socket on the Core.

Naim’ streamers have always provided a generous amount of power on their USB ports, so I would be very surprised if this wasn’t the case with the servers too. If you want actual figures, you’ll have to ask Naim.

I guess the $64,000 question is what constitutes a “generous amount of power” and where does NAIM specify this?

Tried - got no response.

Naim don’t publish this information in the specs, just ask them. Getting a response from their support service seems difficult these days, try phoning rather than email. Failing that I would get your dealer to ask them.

No worries- I’ll just keep it on the current AC/DC transformer. I think if I were at the point of adding additional and/or higher capacity drives I would prefer to have an separate LPS anyway. It will be awhile before that needs to be addressed. Thanks again for checking into this- much appreciated!

The Core has a built in linear power supply and there is no provision for an external power supply, so you can’t add anything. The Core is designed that you don’t need to worry about these things!

I can only echo @davidhendon here.

I think you are only causing yourself anxiety here where none exists.

Anything that I have used for backup purposes that plugs directly into the USB port is directly powered by the Core with no issues whatsoever. I did my original backup on an unused 5.5 inch SATA hard drive that had to sit in a separate caddy that was powered from a separate mains socket & also plugged into the USB socket. This worked fine but was rather ungainly. I then purchased a couple of ‘pocket’ USB drives, plugged into & powered from the Core, & these work in exactly the same way, but with much more convenience & far less unsightly looking, than the old, 5.5 inch SATA drive.

Hi David-
I get it- I’m a talking about providing power to the drives in the way that @Canaryfan described below, basically not using the USB for power.

Thanks- no anxiety, just wanting to make sure I’m not over taxing the buss. I currently have two drives (2TB ea) but will be expanding upon that in the coming months for more storage. I think providing power to a separate drive enclosure is the way to go.

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