Voodoo Lab

Hi everybody!
i'm new here
and italian ...so i apologize for my english..
here is my problem.
i use the GCX since long time but lately i noticed that it started an annoying ground loop everytime i plug the guitar in the dedicated input in the front
whatever is buffered or not...
the problem is sorted if i plug directly into a loop in on the rear.
i tried to change patch cable (i use GL's) or everything else it could help this out.
i thought it could be caused by a transformer misplaced but it is not..i swapped every single thing i have in my rack... changed positions, put aside,took'em off...
the buzz is still on...
can anyone help me please?...
thank you

You can do one of two things to solve this now that you have narrowed the problem down to the front panel inputs but not when going directly to the first loop.

-You can use a product known as HumFrees on the rack ears of the GCX to isolate it from the rack rails.
-OR-
-You can lift the chassis ground connection found inside the GCX.

The GCX chassis ground connection is a screwed down ground lug that is located behind the front panel jacks. To access it you will need to remove the top cover of the GCX. Remove the screw, pull the ground lug out of the way and re-install the screw so it still holds the circuit board securely. Its probably a good idea to wrap the ground lug with electrical tape to insulate it from accidentally touching anything else. Replace the top cover and you are done.

well!!!
i just lifted the ground connection inside and the hum is gone!
what i don't understand is why this happened...
before i had a rack system and there was no noise at all ...since i put a furman pl-plus power conditioner which is supposed to avoid theese things it started giving me ground problems and noises...
anyway...
now it's all quiet and sounding good
so i thank you and i appreciate your help