i have 2 american audio CDI 300 tables both of them humm no matter what i hook them up to. am i missing something i found no ground spot on them? plz help if any ideals and or solutions.

The original CDI-300 has a 3 pronged cord. It must be used in a grounded outlet, or you can experience this issue. Are you using a ground lift adapter? Is the unit plugged into a socket strip, or PDU? have you tried it on a different outlet?