No one has touched on this yet. So try this: 1st hook up the amp to the speakers ONLY. Do not hook the preamp to it. Is hum still present? If so, the amp has a noisy transformer. If not, connect the pre to the amp but dont hook anything else to the pre. Got noise? Proceed on in this way to find out what component is actually causing the ground loop if there is in fact one. I have had a similar problem and found that there was no ground loop at all...I would try this trick before you go any further with the grounding to find nothing is "wrong".
buzzzzz, where did i go wrong?
The setup:
spectral monoblock amps
spectral preamp
theta front end
The NEW DEDICATED CIRCIUTS
4 separate circuits each with fuses jumped off the main box and grounded to the main box
one circuit for each monoblock
one for the preamp
one for the digital front end (MIT power conditioning)
the amps and preamp each share a supplemental grounding rod. The digital end has its own supplemental ground rod
The outlets are all FIM880. These do not have an isolated ground (could that be the problem?)
I still have a buzz.low but audible; it goes away when I lift the ground from my amps. I assume I have a ground loop but I am not sure how or what I do about it. I assume I have made some awful basic error but not sure how.
I know for instance from the posts that Garfish uses three supplemental grounding rods. Maybe I should have tied all those together? any other ideas
spectral monoblock amps
spectral preamp
theta front end
The NEW DEDICATED CIRCIUTS
4 separate circuits each with fuses jumped off the main box and grounded to the main box
one circuit for each monoblock
one for the preamp
one for the digital front end (MIT power conditioning)
the amps and preamp each share a supplemental grounding rod. The digital end has its own supplemental ground rod
The outlets are all FIM880. These do not have an isolated ground (could that be the problem?)
I still have a buzz.low but audible; it goes away when I lift the ground from my amps. I assume I have a ground loop but I am not sure how or what I do about it. I assume I have made some awful basic error but not sure how.
I know for instance from the posts that Garfish uses three supplemental grounding rods. Maybe I should have tied all those together? any other ideas