Specifically i am using a Denon 395 with a Ground terminal on the rear panel. I am not referring to a power cord.The Denon 395 has a two wire power cord and plug. The power wiring inside the unit is doubled insulated and thus the unit does not require an earth ground. An earth ground could actually introduce noise into your audio system.
What i may do is get a 10 Gal dirt filled pot and sink the wire right into it on a tent stake or something.
11-05-14: Roscoe50
The earth does not possess some magical mystical power that sucks nasties from our audio systems. That is a myth.