2. pc-audio
  3. 1150170453

any words of wisdom for usb noise problems?

i thought usb connections would be trouble-free after placing waveterminal u24 between my desktop pc and the dac in my panasonic reciever (office system). itunes runs dead quiet there. i am trying to implement a pc feed into my levinson preamp in main system. when the usb cable makes contact between my laptop pc and the u24 running into the preamp i get substantial noise, which is substantially worse when a usb hard drive is also attached.i googled "usb noise" and saw references to some midi users' and photo printer issues and some filter products (argh!- hope to avoid this step). also mention of computer screens as possible culprits any suggestions or similar experiences?
wkraft
vfoostdijka929
3 posts
 
Or, instead of a DI-box, an inexpensive ground loop isolator:-)
hagtech
173 posts
 
The problem is likely a solid connection between PC ground and audio system ground. This is an issue with many USB DACs. A lot of them do NOT offer galvanic isolation, hence, much of the noise from one system enters the other.

This is EXACTLY why I use s/pdif transformer isolation in my USB dacs and converters. You won't need to unplug your PC wall-wart.

jh
audioengr
3,282 posts
 
As long as we are all advertising here, I'll pipe in too.

This is precisely why I use pulse transformers to galvanically isolate the PC from the Audio System.

Steve N.
Empirical Audio
Manufacturer
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