The Neo Geo AES consoles already have RGB to their output ports, ready for use with CleanRGB cables.

You can go ahead and simply connect the CleanRGB cable to any Neo Geo AES model and you are good to go.

As the Neo Geo AES models all vary, and all have different internal RGB circuit designs, I would highly recommend opening up the console, and checking out if you need several mods for improved visuals.