Re: [LAU] USB cable with ferrite core

From: Ralf Mardorf <ralf.mardorf@email-addr-hidden-dsl.net>
Date: Thu Dec 29 2016 - 13:33:52 EET

On Thu, 29 Dec 2016 01:56:37 +0000, Schatzman, James wrote:
>1) Perhaps it is not so much the issue of whether the cable has a
>ferrite RFI suppressor but the quality of the cable that is important.

Saw + pincers = ferrite core removed = no xruns anymore

I guess it isn't fortuitousness and the culprit indeed was the ferrite
core.

>I recommend that you use a quality USB 2.0 spec'd cable. Better yet,
>use a USB 3.0 cable.

You are aware that the audio interface has got a type B socket?

http://blog.macsales.com/wp-content/uploads/2012/07/USB-BTYPES.jpg

>2) Unfortunately, USB is inherently noisy. Using a ferrite to reduce
>common-mode currents in the cable is, in principle, a good idea.
>However, there are potential issues.
> Either or both the sound card and your computer's USB port may not
> properly isolate the signal and power grounds, and there may then be
> noise issues if the two grounds are not electrically the same. When
> you install a common mode choke (the ferrite), you are effectively
> isolating the two grounds. This should be fine, but if either sound
> card or USB port are not properly engineered, there could be a
> problem. You could try running a wire (16 gauge or larger) from the
> chassis of the sound card to the chassis of the computer. Do not put
> a ferrite around this ground wire.

There were xruns, not just analog noise issues.

>3) Another potential issue is the sound card power supply.
>Unfortunately, almost all power packs sold these days in the U.S. are
>Chinese switching power supplies which produce TREMENDOUS RFI. You
>could try a linear power supply instead, although they are getting
>harder and harder to find.

Sure that's why I just in case purchased a cable with a ferrite core.
Actually there are no issues without ferrite core.

Regards,
Ralf

OT: Voodoo, the PreSonus inputs and MIDI in and out work with my iPad,
but all output channels are silent. Here is a list of devices, known to
work with iOS devices, the PreSonus is one of them, but actually it
doesn't work here:
http://www.wavemachinelabs.com/Support/auria-audio-interfaces
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Received on Thu Dec 29 16:15:01 2016

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