how do you ground RCA's?)

They're supposed to be connected to the ground of the equipment at each end through the outer shield (or one of the wires if you have twisted pair RCAs), unless you have RCAs with only one end of the shield connected to the connector (can solve some ground loop problems).

To add extra grounding to an existing RCA cable, I'd probably solder on a wire to the outside of the connector (the springy part) - quick and easy. But exactly how would depend on the type of RCA connector. For instance, on the ones on a MkI I'd try to screw it apart and solder to the terminal directly (looks neater), but if the RCA plug is molded around the cable I'd just solder to the outside...

/Michael