This is what I tested with:
2x Gemei A330 (one is v1.0 firmware, the other is v1.1 firmware)
1x Dingoo A320 AV-OUT cable
1x Dingoo A330 AV-OUT cable
1x Random AV-OUT (mono) cable
1x Vizio Hi-def Flat Screen LCD TV
1x Old ass TV
The video plays fine, shows up in color, is in the correct aspect, etc. Games also play fine, show up in color, etc. The audio only "buzzes" with all 3 AV-OUT cables, tested on both TV sets, with both Gemei Units. I further tested all 3 cables on 2 Dingoo units and they work correctly (no buzzing, etc). The audio for the Gemei units, while buzzing on the TV, plays fine out the Gemei speakers. Turning off the speakers from the software menu changed nothing.