buzzzzz, where did i go wrong?

OK this is starting to drive me batty.
Today's events included changing the main system ground. We also tried all combos of grounding rods including none except for the main system ground, 2 supplemental rods tied together, all on one supplemental rod...you name it I think we have tried it. we also went through the whoel house flipping each circuit on sequentially but no single breaker added to the buzz effect. It seems to happen after the preamp and teh digital end are tirned on. It is there when only the preamp is on and is slightly greater wheen the digital end is turned on. I am actually starting to wonder if my cables are a problem . They are MIT and are singled ended. Still moving the cables around has no effect.
i notice that cheating the amps takes away teh buzz leaving a small hiss. Maybe this is noise coming in on the neutral?
When you tie the grounds together does that just mean passing a copper wire between them? Does anyone have anyo other ideas?
JD

Maybe you should take the preamp to a friends house and see if it does the same thing.... - Dan

JD, drop me an email at your convenience. Sean
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I've done similar circuit and grounding uprades.The key as others have mentioned is your using the new rods to supplement your existing service ground lowering the overall resistance.Spacing of the rods is important,they should be at least six feet from the service ground and six feet apart and each rod must be tied back(with a separate wire) to the same point in your panel as the service ground.Don't tie the rods together as you want the rods connected in parallel not series.Also you should have an isolated ground on your outlets for each circuit and each ground wire should be connected back to the same point in your panel as your service ground and rods.This is the essence of a star grounded system with ONE low resitance pathway to earth.If your using your fuse connections as a subpanel in some kind of enclosure make sure none of your neutrals are bonded to it.If your using in-line fuses you won't have this concern.

Sean,
I mailed you but I don't think you got it. I think there is a problem. Could you mail me?
Thanks
JD