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 Forum index » Reviews, Editorials and Commentary » Reviews, Reports and Interviews
Olimex USB ISO isolation adapter
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mosc
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PostPosted: Tue Jan 10, 2012 3:18 pm    Post subject: Olimex USB ISO isolation adapter
Subject description: a good solution to USB noise problems
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The Olimex USB-ISO is a small adapter/circuit board designed to provide electrical isolation and noise suppression for USB devices.

The problem:

There are many forum topics on electro-music.com and other forums where people report having serious noise problems when connecting USB audio devices to computers. There are many in the Clavia G2 sub forum, but these problems aren't unique to Clavia products.

I personally have never had these problems, until recently. I bought a Allen & Heath Zed 14 mixer which, when attached to my hp laptop via USB started generating devastating noise. Not hum, but a digital raspy whine - very annoying. My suspicion was there noise was being transferred to the mixer via the USB ground.

My first approach to eliminating the noise was to remove all of the main grounds from the mixer and the computer with ground lifter plugs, but to no avail. The noise didn't even go away when running the computer on internal batteries.

The device:

A bit of internet research brought me to the Olimex USB-ISO device which I got from Mouser Electronics, http://www.mouser.com . See http://www.mouser.com/ProductDetail/Olimex-Ltd/USB-ISO/?qs=sGAEpiMZZMsyM1rGGtQxrO1HI6bIq7Ze

It was pretty cheap at about $41 US. There are many other products that you can buy, but from reading the specs, I figured this one would do the job and it was the least expensive alternative I could find. You pay more with other devices for more voltage isolation and a more robust physical design. This one is rated at 1000 volts. You can get them for 4000 volt isolation, maybe even more. For audio work, that isn't necessary.

Results:

I got the thingie today, and hooked it up between my computer and mixer. I didn't use an external power supply, although you can plug one in if you need to. The result was superb; all audible noise is eliminated.

Yes, the USB still works and the audio sounds great.

Impressions:

Best of all, it does the job - no noise. I'm happy.

The down side is that the devise is very flimsy and minimal in its physical properties. It is essentially a small circuit board (2.2 X 1.47 X 0.53 inches) ( 54 X 37.5 X 14.5 mm) encapsulated with one layer of shrink wrap tubing. I suspect that after some unknown period of time the shrink wrap will start to come undone, but I'll just wrap it up in black electrical tape. It's minimal, but it's good enough.

You will need to get another USB patch cord to use with this device.

Can you get the same result by cutting the ground and power supply connections is a USB cable? Maybe; depends on the circumstances. I didn't try that because I don't have the patience. This device provides complete isolation of the USB signal lines and the DC power.

I suggest that if you experience USB related noise, get one of these, or something similar, and move on the the next exasperating problem. Smile

Pictures of the device are included below showing the box it comes in, and views of both ends so you can see what kind of connectors it has. A 1/4 " phone to 1/8" mini plug adapter is shown to give a sense of size.

Posted Image, might have been reduced in size. Click Image to view fullscreen.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Posted Image, might have been reduced in size. Click Image to view fullscreen.

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Last edited by mosc on Tue Jan 28, 2014 4:03 pm; edited 1 time in total
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dorremifasol



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PostPosted: Sat Jan 14, 2012 5:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

Nice finding! through a bit expensive...
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mosc
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PostPosted: Mon Jan 16, 2012 1:42 pm    Post subject: Reply with quote  Mark this post and the followings unread

dorremifasol wrote:
Nice finding! through a bit expensive...


A bit. But it makes me wonder why Allen & Heath didn't build in ground isolation. One should not need such devices if the gear was properly designed.

sigh

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dorremifasol



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PostPosted: Mon Jan 16, 2012 1:47 pm    Post subject: Reply with quote  Mark this post and the followings unread

I think exactly the same. The G2 is the noisiest synth in my setup, in part because of the USB, but it's also the most incredibly powerful and well thought. How strange!
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mosc
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PostPosted: Mon Jan 16, 2012 2:11 pm    Post subject: Reply with quote  Mark this post and the followings unread

dorremifasol wrote:
I think exactly the same. The G2 is the noisiest synth in my setup, in part because of the USB, but it's also the most incredibly powerful and well thought. How strange!


Get one of these goodies then. Idea

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mwatkinsevang



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PostPosted: Sun Jul 29, 2012 9:08 pm    Post subject: USB ISO Reply with quote  Mark this post and the followings unread

Hey man...I just read your post and ordered the USB Iso...

We have almost the same exact issue with our brand new Allen & Heath 428 that has the USB recording out...We plug directly into our computer and record onto that computer.

When I plugged in headphones directly to the board, I can't hear the high pitched whine...but when we listen to the recording, its very noticeable when theres no one singing or talking during recording, so its in the background..

My question for you is how do I hook up the USB Iso device...on your picture you showed a 1/4 to aux female adapter...that confused me as I only thought I would be using one more USB cable..where does the adapter you showed come into place? Sorry if my questions are dumb, I am just a volunteer and don't know much about sound yet, just learning...thanks for any help you can give!
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Blue Hell
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PostPosted: Mon Jul 30, 2012 9:18 am    Post subject: Reply with quote  Mark this post and the followings unread

mwatkinsevang .. I think this was the right place to ask and duplicate posting is being frowned upon ... anyway, I have removed that duplicate.

The audio plug is just for size reference, the device has USB in and USB out, so indeed you would need just one extra USB cable.

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mwatkinsevang



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PostPosted: Mon Jul 30, 2012 9:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Blue Hell wrote:
mwatkinsevang .. I think this was the right place to ask and duplicate posting is being frowned upon ... anyway, I have removed that duplicate.

The audio plug is just for size reference, the device has USB in and USB out, so indeed you would need just one extra USB cable.


My apologies Blue.... I only duplicated because of the age of this thread and your private message and email options are broke..I tried sending multible PM's and Emails to the user who posted this and when I click "submit" it says "php error" or something to that effect....tried every browser I have.

Sorry again and thanks for the reply.

So I plug my USB into board and then into ISO and then computer..correct?
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Blue Hell
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PostPosted: Mon Jul 30, 2012 10:03 am    Post subject: Reply with quote  Mark this post and the followings unread

Broken ... hmm .. not at the moment it is .. strange.

Anyway, yes to your question :-)

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dorremifasol



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PostPosted: Thu Jun 19, 2014 11:17 am    Post subject: Reply with quote  Mark this post and the followings unread

Following Mosc's advice I bought the thing and I must say it works like a charm! Much better than my previous solution.

http://www.ebay.com/itm/Olimex-USB-ISO-Full-speed-USB-isolator-1000VDC-audio-dac-noise-ground-earth-loop-/271324890162

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