I will get some alligator clips to test the grounding as you did. My sub's plate would look a bit funny because mine is facing out so I can adjust the volume easily but I don't really care as long as the sound comes out right. I just received a pair of Belkin surge protectors and will try the coax connection as suggested by Mark Seaton. I will certainly get a pair of power conditioners because I need one for the audio tower and one for the bass units.
I tried to attach a picture was not allowed. Strange.
Music: PS-LX300USB, DVD-S1800BL, RX-A1030, Sony Blu-ray, Pioneer LD, PS3, NHT Absolute Towers, NHT Absolute Zeroes, Pinnacle center & surrounds, VTF-2 MK4, MBM-12 MK2, Samsung 36xx
HT: Sony BDPS5200, AVR-790, Infinity Primus 363s, Energy Take center & surrounds, Klipsch SW-350, Pinnacle Subcompact8, LG BL5900