In reply to:

Yes. I tried every combination possible, from pulling all the grounds to one central location and also by seperating them all apart and trying different places. I assume that when grounding, though, any metal bolt that connects to the chassis of the car would be sufficient. Is this a correct assumption or no?

Technically, yes - althugh you shoudl try grounding everything back at the battery to see if the sound improves...
-mark

...proud to have owned one of the first Mark I units

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