Take the 2-minute tour ×
Sound Design Stack Exchange is a question and answer site for sound engineers, producers, editors, and enthusiasts. It's 100% free, no registration required.

I was looking at buying a USB Isolator; however, I ended up buying a powered four port USB 3.0 instead. It was roughly the same price, has a higher speed, and serves a useful alternative function.

Do these two devices work any differently. They're both powered externally? Will both of these be equally effective at eliminating a ground loop?

share|improve this question

migrated from avp.stackexchange.com Jan 27 at 15:24

This question came from our site for engineers, producers, editors, and enthusiasts spanning the fields of video, and media creation.

1 Answer 1

A USB hub will probably tie all the grounds together, so that won't help you break your ground loop.

Update: I just checked a Belkin F5U701 hub with my multimeter (in continuity mode). The grounds of all the USB ports are tied together and tied to the ground of the power supply.

share|improve this answer
    
Why would they do that if it takes an external power supply? Why not just use the ground from the transformer? –  Evan Carroll Oct 31 '12 at 21:34
    
I can't help you with the why part - better to ask at electronics.stackexchange.com, where people with experience designing USB hardware can answer. I updated my answer with some information about a hub that I have lying around. –  ObscureRobot Oct 31 '12 at 23:23
    
@EvanCarroll It's much simpler. The actual data signal levels are relative to ground, so if they wanted to separate the grounds they'd have to convert the signals as well — all of which is extra complexity mostly unrelated to the digital-logic-type functions of a USB hub per se. –  Kevin Reid Nov 1 '12 at 1:41
    
hrm... why are digital signals relative to ground? I thought that was a function of analog signals. I thought digital signals were on or off? Sorry if it's a stupid question, I don't work on such low levels though. –  Evan Carroll Nov 1 '12 at 2:48
1  
Digital signals are a special case of analog signals. Voltage is a potential difference, so you need something to reference your signal against. –  ObscureRobot Nov 1 '12 at 5:25

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.