USB Galvanic Isolation - Is that really necessary?

[K3cT]

The the other day I've received an Analog Devices newsletter which showcased their new USB isolator chip, the ADUM4160 and to my surprise this chip has been discussed quite intermittently here. I'm going to make this quick: is there any advantage of using this chip if my USB DAC does not pick up any ground loop or noise whatsoever? Isolating hum seems to be the main function of this chip no?
 
Thanks in advance.

 

[ninjikiran]

I'll just gather some information I have read around head-fi.
 
If its not protected, good.
 
If it is protected already, you risk damaging Sound Quality.
 
Sorry for the simple post but I don't know personally.  Those two statements above seem to be the common ground most people have.
 
At the price of the device itself( usually around $50) it is not much of a risk especially since you can sell it and get most of your money back if it does nothing or makes things worst.

 

[K3cT]

ninjikiran, I'm a bit at a loss. What do you mean by "protected"?
 
I'm also trying to understand how galvanic isolation can lead to an improved SQ.

 

[Dynobot]

I too was dubious to say the least, but I like to try different things just to see [listen] for a difference.
 
The difference is like cleaning both side of your windshield vs only the outside. 
 
Clean the outside only, sure its nice and clean you can live with it as it offers a nice view to the outside word....but you notice the windshield as being there without even really paying it attention. 
 
Clean both sides really well and all of a sudden it seems like there is no window there at all, just simple clarity. 
 
With both sides clean and you view without any obstruction in your mind it becomes obvious what the difference is....  If you wear glasses, clean them really well so that you don't see the lens.  This is what the Adum does, once its in place USB without it is blurred and vague in comparison.
 

 
Quote:

The the other day I've received an Analog Devices newsletter which showcased their new USB isolator chip, the ADUM4160 and to my surprise this chip has been discussed quite intermittently here. I'm going to make this quick: is there any advantage of using this chip if my USB DAC does not pick up any ground loop or noise whatsoever? Isolating hum seems to be the main function of this chip no?
 
Thanks in advance.

 

[ROBSCIX]

Many around are using them.  Some products based on that chip use internal USB power BUT others allow an external power source to be used.  These are the units that many seem to like around here...  They are so cheap you can experiment with them without too much worry.
I have used one for quite awhile now, I have an external battery source connected to it and it works great.

 

[ninjikiran]

If your devices USB input is already isolated, which I assume the only kind of isolation is galvanic when talking about USB.  I couldn't explain it very well though, really I am shooting blanks with this topic, parroting other comments.
Quote:

ninjikiran, I'm a bit at a loss. What do you mean by "protected"?
 
I'm also trying to understand how galvanic isolation can lead to an improved SQ.

 

[Dynobot]

The Adum actually supplements the USB power with its own power from a Walwart or Battery.  It not only isolates the Dac from the PC ground but all the power from the PC from what I can tell....
 

 

[wuwhere]

Do you know where to buy a USB isolator?
 
Quote:

The Adum actually supplements the USB power with its own power from a Walwart or Battery.  It not only isolates the Dac from the PC ground but all the power from the PC from what I can tell....
 

 

[Dynobot]

Quote:

Do you know where to buy a USB isolator?
 

 

I bought mine from here
 
http://www.circuitsathome.com/products-page/usb-interfaces

 

[wuwhere]

Did you buy the kit or the built one?
 
Quote:

I bought mine from here
 
http://www.circuitsathome.com/products-page/usb-interfaces

 

[Dynobot]

Quote:

Did you buy the kit or the built one?
 

 

Built.....

 

[Nebby]

With the default circuits@home board, the computer provides power up to and including the chip and the power source for the downstream device is provided by the dc input. I'm thinking of using an Amb Sigma25 to power the ADUM along with the gamma2.
 
Quote:

The Adum actually supplements the USB power with its own power from a Walwart or Battery.  It not only isolates the Dac from the PC ground but all the power from the PC from what I can tell....
 

 

[wuwhere]

That's good, downstream power is isolated. Is the AMB a kit?
 
Quote:

With the default circuits@home board, the computer provides power up to and including the chip and the power source for the downstream device is provided by the dc input. I'm thinking of using an Amb Sigma25 to power the ADUM along with the gamma2.
 

 

 

[Nebby]

Nope, Amb provides no kits though you could probably go one up and get a sigma11 kit from glassjaraudio. With a decent sided transformer you could have a usb isolated hard drive running with isolated power

 
 
My current plan is to build the isolator into a box sized similar to the gamma2 and a sigma25 in a similar box; that would result in a mini tower of power

 

[wuwhere]

I'm thinking of using 2 9v rechargeable li-poly.
 
Quote:

Nope, Amb provides no kits though you could probably go one up and get a sigma11 kit from glassjaraudio. With a decent sided transformer you could have a usb isolated hard drive running with isolated power

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My current plan is to build the isolator into a box sized similar to the gamma2 and a sigma25 in a similar box; that would result in a mini tower of power

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