This is a response to review that I wrote on Amazon recently:
I bought this a couple of weeks ago to expand the number of 3.0 ports on my desktop. And I bought a backlit keyboard. Today I had the computer off to plug both in for the first time.
Keyboard was first on a 2.0 port. Next was the hub into a 3.0 port. When I plugged in the power supply the keyboard lit up. Played around with it and verified it is backfeeding voltage to the other usb ports both 3.0 and 2.0 ports.
Googling online showed problems with poor design hubs backfeeding. Anything from boot problems to possible data loss.
One solution other’s have tried is cutting the 5 volt power line between the computer and the hub so all devices plugged into it get their voltage from the hub.
Not sure I like that. If yhe hub is that poorly designed what are the chances the power supply is poorly designed too. I’m not about to take a chance with my data. This tjing is going in the trash. Based on this bad design I’ll likely avoid any Gearhead products.
The response I wrote:
I have went through two UH8000AL hubs. I still have the second one but I do not know if I even want to try and test it on anything because:
The first time I used one of these hubs was with a Startech PEXUSB3S25. I was having major issues but did not document it. What I do remember is that after a while one Corsair USB 3.0 Survivor stick, the Startech PEXUSB3S25 USB addon card, and the HUB itself all stopped working. I did have the LP4 connector on the Startech PEXUSB3S25 plugged in.
I was using a MALE to MALE USB 3.0 keystone jack from Monoprice (Monoprice PID number 7836) and I figured it was that at the time. That it was of low quality and that it just crossed some things that were not to be crossed. Though, you really cannot mess up a MALE to MALE USB 3.0 keystone jack and nothing appeared to be wrong with it.
I ended up getting a new Startech PEXUSB3S25, a 7153902 Shaxon Pass Through USB 3.0 Keystone jack (14.99 a piece, and I could only find one vendor), and I had the GearHead UH8000AL RMAed. After putting it all back together it has been working for about a year. I am thinking, problem solved, it had to be that keystone jack.
About a month and a half ago I go to plug my Corsair USB 3.0 USB stick in to the GearHead hub and the system does not see it. I take the hub out and plug directly into the keystone jack and the port is dead. Another fried Startech PEXUSB3S25 PCIE card. I immediately jump to the card being bad and that possibly they are just bad cards. I also wonder if there was a ground loop between the hub and the card.
Honestly I am trying to figure out the issue still but this review I am commenting on may give me a bit of insight into what has been going on. I do not have a backlit keyboard like this reviewer but if this hub is pumping power into the Startech PEXUSB3S25 I could see this being an issue.
I ended up purchasing a different hub. I purchased a PLUGABLE USB3-HUB7BC that does not draw power from any USB port, it should not add it either as it is specifically designed that way.. I found it after reading a audiophile forum post about users needing more USB 3.0 ports for their DAC’s. I figured if they used it, they must not see any feedback or bad loops. It does not have ground loop isolation though (after talking to the manufacture) but now that I have read about this backfeed issue I have my doubts about a ground being any issue at all. I am willing to bet adding power to a 5v line on that card would fry it after time.
The only issue with this new PLUGABLE USB3-HUB7BC is that initially it was not working with my Corsair USB 3.0 Survivor stick. The manufacture of the PLUGABLE USB3-HUB7BC actually states on the website that it may not work correctly with PCIE USB 3.0 cards but after talking directly to them, they put that statement there just because the PCIE cards often have old/outdated drivers that do not have proper HUB support. The latest linux kernel does and after figuring out that a different Corsair USB 3.0 Survivor stick works just fine I now wonder if the Gearhead hub messed up my most used Corsair USB 3.0 Survivor USB stick.
The problem is that the sticks may be different revisions and without taking them apart and looking, I cannot know.
I have a feeling that the Gearhead hub has been destroying my devices also, even slowly.
I did know about this because of the Raspberry Pie issues with backfeed but to power a keyboard across ports? I think I should figure out a way to test this and simply.
I wonder if this will work…will it power itself when the hub starts to back feed:
Got that from: http://www.howtogeek.com/228869/how-to-monitor-your-usb-device-power-usage-and-output/
That would be proof enough. I could also use a male to male adapter and try it that way. I will get one and try it.
Here is a link about in depth testing of USB chargers also: http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html