USB Ground Loop Isolator - Full speed or High Speed?

Wait, the noise is getting stronger when you move the mouse around?

This suggests two things:
1) wireless mouse: maybe your guitar is picking up EMI? Does the noise go away if you turn down the volume on your guitar?

2) cable mouse: grounding issue on your PC; definitely.


If changing USB cables worked, then maybe it was due to cheap cables after all. Time to get an audio-grade USB!
 
Zwiebelchen said:
Wait, the noise is getting stronger when you move the mouse around?

This suggests two things:
1) wireless mouse: maybe your guitar is picking up EMI? Does the noise go away if you turn down the volume on your guitar?

2) cable mouse: grounding issue on your PC; definitely.


If changing USB cables worked, then maybe it was due to cheap cables after all. Time to get an audio-grade USB!
Click to expand...


Thanks for the suggestions. I'm using an apple bluetooth trackpad (my machine is running OS X) but turning guitar volume down has no effect. In fact the axe only needs to be on and connected (the preset can be blank) to hear the noise. It's not just the mouse that makes the noise, loading programs etc and generally making the computer do anything generates various tones and hums in the monitors.

However, I also have a pair of rubbish Dell computer speakers hooked up to the computer for checking mixes and they never get any noise from the computer - only my active monitors get ground noise from the computer. My active monitors are on the same power conditioner as the Axe and computer. Axe is connected to the desk via Balanced XLR's as are the monitors.

Whats an audio-grade USB cable? I assumed they were all the same - which they obviously aren't! If i've got a pile of USB cables is there any way to tell which ones are "audio-grade"?

Thanks again :)
 
ralphonz said:
Thanks for the suggestions. I'm using an apple bluetooth trackpad (my machine is running OS X) but turning guitar volume down has no effect. In fact the axe only needs to be on and connected (the preset can be blank) to hear the noise. It's not just the mouse that makes the noise, loading programs etc and generally making the computer do anything generates various tones and hums in the monitors.

However, I also have a pair of rubbish Dell computer speakers hooked up to the computer for checking mixes and they never get any noise from the computer - only my active monitors get ground noise from the computer. My active monitors are on the same power conditioner as the Axe and computer. Axe is connected to the desk via Balanced XLR's as are the monitors.

Whats an audio-grade USB cable? I assumed they were all the same - which they obviously aren't! If i've got a pile of USB cables is there any way to tell which ones are "audio-grade"?

Thanks again :)
Click to expand...
Not all USB cables are created equal, that's all I can say. With "audio grade", I meant one that is... not a cheap-ass of-the-shelf cable or the charging cable for your mobile. Just try to find a quality USB 2.0 cable and it should be fine.

Can you give us a quick sketch of your routing? Are your monitors connected to your Axe or the PC?

Also, have you tried plugging the PC into a different outlet?
 
Tried plugging the PC into a different outlet - no change.

Monitors are connected to the Mixer, Axe is connected to the mixer. The only connection the computer has to the mixer is firewire.

- Killing the Axe's channel on the desk stops all noise.
- Unplugging the Axe FX USB cable stops all noise.
- Plugging PC on-board sound straight into active monitors (Unbalanced RCA) gives the worst noise in the world!
- Dell Computer speakers never make noise.

Here is a quick diagram of my set-up:
set-up-quick-sketch-01.jpg

I've tired plugging the computer into the Power conditioner and a completely different wall socket with no change.
 
ralphonz said:
Tried plugging the PC into a different outlet - no change.

Monitors are connected to the Mixer, Axe is connected to the mixer. The only connection the computer has to the mixer is firewire.

- Killing the Axe's channel on the desk stops all noise.
- Unplugging the Axe FX USB cable stops all noise.
- Plugging PC on-board sound straight into active monitors (Unbalanced RCA) gives the worst noise in the world!
- Dell Computer speakers never make noise.

Here is a quick diagram of my set-up:
View attachment 26751

I've tired plugging the computer into the Power conditioner and a completely different wall socket with no change.
Click to expand...

Does the noise floor stop/change when you unplug the firewire?
It appears to me that the firewire, USB and XLR's from the Axe to Mixer are your ground loop.
 
Does the noise floor stop/change when you unplug the firewire?
It appears to me that the firewire, USB and XLR's from the Axe to Mixer are your ground loop.
Click to expand...

I gave it a try but unplugging the firewire cable makes no difference, the noise is still there on the Axe channel of the desk. I've tried different channels as well, just to make sure ;-)
 
Do you have a friend that has a laptop he can bring over just so you can try out if this setup works better then?
At this point, we should rule out every possibility.

Also, btw, have you tried the ground lift switch on the back of the Axe?
 
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