Buzz/hum through speakers

When I turn on my system, I get a buzz/hum through all the speakers. I have everything hooked through my Furman line conditioner. I have plugged my amp directly throught the wall outlet with only speakers attached to the amp and no noise. I have disconnected everything from the line conditioner one by one and only makes the noise when the pre and amp are turned on together. My dealer gave me something called Hum X and when I plugged the Furman into the Hum X, noise still there, it's only when I plug the Hum X to the back of the Furman and plug the amp into the Hum X, the noise is gone. Is there any way to get rid of the noise without using Hum X? If I can't get rid of the noise with Hum X, is Hum X holding back the full potential of the amp?