Buzzing source

Just got a new mmf-5 turntable. It is being run through a Parasound phono pre to a Audio Refinement int. amp. The table's ground is connected to the ground connector on the back of the Parasound. when I remove the ground wire, the buzzing gets much louder. All grounded plugs in the system are fitted with "cheater" plugs, then plugged into a power strip which is grounded at the wall outlet. Other than trial and error, does anyone know if there is a main culprit in these grounding problems? Should I be trying to ground the table somewhere else? The buzzing is only occurring when the phono input is selected.