'Mono' as in monochrome. Cables are all the same - I regularly use sound cables for connecting up video and vice versa so long as the connectors are correct.
Use the L and R audio outputs for sound.
It's a long time since I connected an A500 up like this, but I don't remember having lots of static. Have you checked to see if the plug on the A500 and the connectors on your cable are clean? Or perhaps try with another cable - at least you might be able to start eliminating some variables.