Isolated Ground causes ground hum.


Hi Experienced Goner.
I am adding the isolated ground into my music system and when I connected the ground wire into my existing system and it hums badly.
Did I do st wrong?
 Thanks 
Calvin
dangcaonguyen
Post removed 
I hammered three copper rods under the ground then linked them together with a solid 4 awg copper wire and through the exterior wall into my music room.