USB Isolation.

[Welder]

If you’re using USB from a PC feeding a USB Dac that doesn’t have galvanic isolation, or a hard drive to PC, these links may be of interest.

http://electronics-shop.dk/galvanically_usb_isolation.htm?currency=USD
http://diyparadise.com/shop/index.php?main_page=product_info&cPath=3&products_id=124

A bit about the chip and methodology
http://www.dataweek.co.za/news.aspx?pklNewsId=33578&pklCategoryID=44

[serendipitydawg]

Sorry to so cryptic, but have you tried one?

[DSJR]

Could this be a way of "inventing a problem" and then marketing a "solution" for it?

[StanleyB]

Could this be a way of "inventing a problem" and then marketing a "solution" for it?
Like asynch USB ?

[Welder]

Serendipitydawg.

No, I haven’t tried either of the products in the links.
What I did try was constructing a USB power supply using this board. http://www.analog.com/en/interface/digital-isolators/eval-adum4160/products/product.html

I became interested in USB isolation when building a mono USB power hub for my current Dac.
Although the HRT Pro does have galvanic isolation I wondered if using an isolator in the 5V power supply would make any audible difference.
It didn’t and I have gone back to a simple regulated 5v hub.
This doesn’t mean it may not benefit Dacs that do not have galvanic isolation.

DSJR
Possibly, you would need to find that out for yourself.
If USB born noise isn’t in fact a problem for a Dac using this method of data transfer one can’t help wondering why so many Dac manufacturers go to great lengths to try to eliminate it.

StanleyB
I can understand your motives for trying to dismiss asynchronous transfer given it’s not something you are ever likely to be able to implement in your products.
Given the number of respectable and successful Dac manufacturers who have chosen to use asynchronous data transfer, I can’t help wondering if perhaps they have it all wrong and you know better. Time and sales will tell wont they?

[StanleyB]

StanleyB
I can understand your motives for trying to dismiss asynchronous transfer given it’s not something you are ever likely to be able to implement in your products.
Given the number of respectable and successful Dac manufacturers who have chosen to use asynchronous data transfer, I can’t help wondering if perhaps they have it all wrong and you know better. Time and sales will tell wont they?
No you don't understand anything, which is quite clear:). You are keen to use my position as a designer/manufacturer in order to dismiss my comment, instead of taking time to read in between the lines of what the async line is alleging, and pretending to cure. If you can separate yourself from that, then maybe you'll finally grasp the snake oil behind the claims.

As a taster for your study into the subject: the async USB 'inventor' claims that in anything other than his version of the USB implementation the PC is master and the DAC is slave. That's blatant nonsense. Can you name me the DAC receiver chips that are slaves instead of masters of the incoming digital data? All of the Cyrus Logic and Wolfson receiver chips operate as masters to the digital signal. But that is just one of many holes in the async USB smoke screen ;).
By the way, do you understand how async actually works, or are swallowing the designers words without actually chewing and tasting it for substance abuse?


I have no problem with some manufacturers using async. But there are even more manufacturers who do not use it. As to whether they are respectable is something that I cannot say. That's purely another subjective opinion of yours:).

[purite audio]

Stanley you really should read up on async USB.
BR Keith.

[Welder]

StanlyB
I’m going to try to keep this reasonably polite and brief.

“No you don't understand anything, which is quite clear ”
Probably not.

“You are keen to use my position as a designer/manufacturer in order to dismiss my comment,”

I wouldn’t say that I was keen to dismiss your comments for the reasons you give: other reasons perhaps.

“By the way, do you understand how async actually works, or are swallowing the designers words without actually chewing and tasting it for substance abuse?”

Well StanleyB, that rather depends on what you consider to be “understanding”.
I have read a great deal about it and I dare say I could repeat a great deal of what I’ve read, even provide source references if necessary.
However, that doesn’t prove bugger all does it? I managed to get a degree in Math’s and Physics doing much the same.
If however you are asking me if I’m interested in debating the issue with you, the answer is no.
To be blunt Stanley, I’m not interested in anything you have to say which is why I don’t piss all over the threads concerning your products and I would be grateful if you didn’t piss all over the threads I start, which incidentally had nothing to do with asynchronous transfer and was in fact talking about USB isolation.

I hope that seems to be a reasonable request.

[roob]

Stanley
Maybe you should ask Tony L to reinstate your membership to pfm then you can chat to fellow DAC designer John Westlake who is posting there now about your concerns about async usb. I think it would make for an interesting debate.