And this happens on every rig? even with everything bypassed? Gate has no affect?
Are you near florescent lighting?
If you unplug the guitar cable does it still make the noise?
Is the noise also present in the headphones?
Have you tried plugging in to another outlet? Preferably on a different circuit?
Does this happen in standalone and when Pro Tools is open?
Does changing samples rates have any affect?
Do you have problems with the Eleven Rack at 44.1, 48, 88.2, or 96?
What firmware is currently installed on the Eleven Rack?
http://www.youtube.com/watch?v=sFclFceQDg0