Hi,

I have come in to this thread part way through so may have missed something
in which case I apologise.

An isolating USB has its own dedicated power supply (small wall-wart) which
powers one side of the USB while the other side is powered from the primary
device

I had a customer approach me a short while ago with a noise problem in his
recording studio. The problem only existed when he connected to his
audio-card which was part of his laptop computer. Laptops 9and most other
computers) are notoriously bad for noise when connected to other equipment
so I suggested he try this

http://www.dontronics-shop.com/usb-iso-low-full-speed-usb-isolator.html

The problem disappeared immediately and they haven't had a problem since.

This unit is about USD$40

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Phone: +61 (0)2 4340 0938
Web: www.elby-designs.com
Skype: widgetoz

Elby Designs
9 Follan Close
Kariong
NSW 2250
Australia

-----Original Message-----
From: Doepfer_a100@yahoogroups.com [mailto: Doepfer_a100@yahoogroups.com ] On
Behalf Of codotinc
Sent: Saturday, June 01, 2013 2:23 PM
To: Doepfer_a100@yahoogroups.com
Subject: 1 Re: Doepfer 6U Suitcase making sounds




Thanks Laurie --

Not sure exactly what an isolating USB is, so a quick Google shows me that
USB isolators are around $100 !

Perhaps I'm not getting what you mean Can you suggest a way to isolate the
USB -- and this would still provide power for the audio interface

Best,
Jon

--- In Doepfer_a100@yahoogroups.com , "Elby Designs" <elby_designs@...>
wrote:

>
> You could try using an isolating USB.
>
>
> Best Regards
> Laurie Biddulph
> Mobile: 0400 257 645
> Phone: +61 (0)2 4340 0938
> Web: www.elby-designs.com
> Skype: widgetoz
>
> Elby Designs
> 9 Follan Close
> Kariong
> NSW 2250
> Australia
>
>
> -----Original Message-----
> From: Doepfer_a100@yahoogroups.com
> [mailto: Doepfer_a100@yahoogroups.com ] On Behalf Of codotinc
> Sent: Saturday, June 01, 2013 6:41 AM
> To: Doepfer_a100@yahoogroups.com
> Subject: 1 Re: Doepfer 6U Suitcase making sounds
>
> Hi Dieter and Florian --
>
> Thanks for your replies.
>
> Florian: you were right in your diagnosis -- it was my USB-powered
> audio interface. The synth was totally quiet until I plugged it into
> the interface.
>
> So, that's sorted but it's a bit of a pain! Now I need to get a new
> audio interface !
>
> Thanks for your help -- glad to know that my PSU is not stuffed.
>
> Kind regards,
> Jon
>
> --- In Doepfer_a100@yahoogroups.com , Florian Anwander <fanwander@> wrote:
> >
> > Hello
> >
> > to both Nathan and Jon: is this a mechanical sound or does it come
> > from the speakers
> >
> > If it comes from the speakers, disconnect the audio out from the
> > A100 system, and connect a headphone with a mini jack connector to
> > the output of the last module in the audio chain (example: VCA or
> > mixer) and turn it up. Do you still hear the noise
> >
> > If yes, then the problem is in the A100
> >
> > If no, then the problem is in the combination of the A100 with the
> > rest of your system
> >
> >
> > To Jon:
> > Do you use an computer with and USB Audio interface
> > If yes: Is the interface USB-powered
> > If yes: use an interface with an separate power supply.
> >
> > USB-power on Audiointerfaces in a studio like environment introduces
> > HF from the digital signals of the computer in the audio ground.
> > Those are useful only for standalone usage.
> >
> >
> > Florian
> >
>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>

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