How to remove USB ground loop interference, where to connect USB isolator?

Synchronicity

Synchronicity

Inspired
Hi there

I've had a problem with electrical interference and strange "computer glitch sounds" when using the axe fx via USB with my computer, at first I thought it was from my mains power, and although getting a power strip with a built-in interference eliminator/power cleaner, there was still the high end electrical sounds.

I'm thinking of getting this to try and resolve the issue, but I'm not sure how to connect it properly to eliminate maximum noise, for instance even my mouse causes some audible interference when moving it during recording etc...


Anyone have any experience with something like this? -

Amazon product ASIN B00M1QQBJ0

Thanks!
 
Can you give me a bit more info about the audio setup on your computer. Do you listen to play back through a sound card or over a usb device?

You can sometimes use a USB hub to isolate some USB noise, But if the noise is as bad as it sounds like, than the standard audio interface on the computer is also going to probably pickup this noise as well.
 
He's referring to this USB isolator.

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Hey guys, sorry for the gap in revisiting the thread been a hectic couple of days.

My setup is pretty basic, just Guitar > Axe FX II > Direct USB to PC (and studio monitors straight out of Axe FX Output 1)

There is definitely much less interference noise when I am using the axe fx II not plugged into the computer, but some of the noise is also coming from my computer monitor (screen), it's more noticable when using high-gain patches on my strat with single coils, but also present on heavier settings using a humbucker guitar.

If I were to get this device, would the correct way to use it be too plug the Axe FX II into the USB hub/isolator, then that into the PC?


Thanks for your help guys!
 
What kind of pc? Windows, Mac, Laptop or Desktop?

What kind of studio monitors?

What kind of cables between Axe-Fx II and studio monitors? Unbalanced TS, balanced XLR or Balanced TRS?

I had the same issue but finally resolved it but this issue can be caused by many different things, so what resolved my issue may not resolve yours. I wrote a post about all the things that need to be tried to resolve the issue. I'll look for the post now and reply when I find it.
 
Here you go:
http://forum.fractalaudio.com/threads/reamping-using-spdif-and-scarlett-6i6-how.112628/#post-1350204

I'm using a desktop but if you're using a laptop, try disconnecting the power cord and see if you still get the noise when running on battery. If you don't get the noise when on battery then the issue is the poor design of the power adapter and laptop and you may need to get an Ebtech HumX http://www.ebtechaudio.com/humxdes.htm

Just for testing, you can try using an adapter that removes the ground from the power cord but you risk getting shocked. I personally have never gotten shocked when using one with a setup like yours but if someone or a pet touches you while you're touching your guitar strings you both might get zapped or if you touch something that's grounded you might get zapped.

Hope that info helps
 
Oh and regarding the USB Isolator, I think those will only work for USB 1.x devices and not USB 2.0 or 3.0.

USB Isolators say:
Supports USB Full speed 12mbps only, not USB High speed 480Mbps
 
Wait...

That isolator will only help with ground loops. From the description it's not obvious at all that you have a ground loop, or anything wrong with the connection from Axe to your computer. Those high pitched noises from your monitor affect guitar pickups, not the USB cable.

When you unplug your guitar, does the noise go away? If it's a ground loop, it shouldn't. If it does, there's an issue with your guitar and/or instrument cable. Try another cable first. Is your guitar shielded? Is the bridge grounded? When you move away from your computer, does the noise go away/change? When you change orientation of your guitar (like turning it from North to West), does the noise change? Do you have light dimmers? Maybe your neighbors?
 
vangrieg said:
Wait...

That isolator will only help with ground loops. From the description it's not obvious at all that you have a ground loop, or anything wrong with the connection from Axe to your computer. Those high pitched noises from your monitor affect guitar pickups, not the USB cable.

When you unplug your guitar, does the noise go away? If it's a ground loop, it shouldn't. If it does, there's an issue with your guitar and/or instrument cable. Try another cable first. Is your guitar shielded? Is the bridge grounded? When you move away from your computer, does the noise go away/change? When you change orientation of your guitar (like turning it from North to West), does the noise change? Do you have light dimmers? Maybe your neighbors?
Click to expand...

He's correct. Follow his steps before mine, so you can verify if the issue is caused by your guitar, or hum / ground loop. My issue was ground loop, which wouldn't go away even when I unplugged my guitar cable from the Axe-Fx II.
 
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