lots of hum when connected via usb (4cm)

rudomat

Inspired
hi,
when i´ve got my setup connected in 4cm everything works fine...as soon as i connect to the pc via usb, i get really loud hum...of course i want to work with axe edit and need the usb connection...
thanks for hints....
 
Mine does this and it drove me nuts until I figured out it was a dimmer switch upstairs in my living room. I turned it off and it went away.
 
If it happens when you only connect USB, it sounds like it's a ground loop issue, or possibly a bad USB cable.
 
in the past i had this issue,it was ground loop caused but my bogner shivas eff loop,I.bought a ebtech hum eleminator and all was completly noise silent,didn't even need noise gate anymore also,maybe u try this if all else fails☺
ps usb may be different ,just a tip.
 
check your environment REDD is correct dimmer switches are notorious for hum so are things like cables, power warts, cell phones and fans/motor's, I always use reliable power filters like Monster Pro 2000 for home and make sure all gear is isolated on a grounded circuit, I've had expensive guitar cables be the culprit before too where once plugged in I was getting a radio station, and finally there is proximity some places in the home can be a problem for some unknown reason a particular spot in the house has a high EMF or RF field and it affects your gear so try disconnecting all of the gear use one cable at a time switching them out and if space allows even moving things around in the room or house.
 
It's a ground loop. I have had to deal with them here as well. Best solution is to use an Ebtech hum eliminator (about $50). You could also lift the ground on one part of the circuit (3->2 adapter), but that's not as safe.
 
ok, but i don´t get any hum when the whole gear in 4cm is hooked up...but only when i add the usb to pc connection...can it still be that the ebtech tool is the solution...? where should i place it then...?
thanks
 
How does such a hum eliminator work? how do you connect your Axe fx or guitar to it. Is guitar-Axefx- Ebtech? Or guitar-Ebtech-Axe fx? First time I see this hum eliminator.

I too have a hum issue with another machine (a Roland Boutique synth). It needs usb power and when I connect it to the computer there is a loud hum. When I power it with an external usb adapter the noise is gone. Also a ground loop I think?
 
ok, but i don´t get any hum when the whole gear in 4cm is hooked up...but only when i add the usb to pc connection...can it still be that the ebtech tool is the solution...? where should i place it then...?
thanks

Nope - I was wrong. For some reason I was thinking in terms of Axe-FX II (what I have). The Ebtech is strictly audio, and won't do anything for USB-introduced ground loop. You need to find a way to break the ground chain. Look's like Bodde (above) has solved this by introducing a USB powered hub. I will tell you that in my case, it didn't solve the problem. Could be one hub manufacturer isolates grounds and another does not.

Out of curiosity, are the AX8 and the computer on the same A/C power circuit?

And somebody asked how hum-eliminators work... simple: they are transformers... the input and the output are electrically isolated by a gap. The signal is passed by entering on the primary, and being magnetically induced into the secondary - the output side. Voila - physical separation!
 
And somebody asked how hum-eliminators work... simple: they are transformers... the input and the output are electrically isolated by a gap. The signal is passed by entering on the primary, and being magnetically induced into the secondary - the output side. Voila - physical separation!

So how exactly do you connect your Axe fx to it? is it Axe fx output to hum eliminator en then from hum eliminator to your soundcard or mixer/amp?
 
I have the most weird ground loop problem in the past and I tried everything. The only way I got rid of it was buying a Furman power conditioner and ensure that everything was plugged to it: AX8, amp and laptop charger.

Then, it is dead silent! Here is the Furman I got (and I tried those monster power filters and the ebtech hum eliminator with no success):

Furman M-8X2 Merit Series 8 Outlet Power Conditioner and Surge Protector
Amazon product ASIN B003BQ91Y6
 
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