I am looking at getting the YoungNuo 603 reciever/transmitter combo for use on a Canon 7D and 580EXm2, I know these cheap units are popular, but does anyone know what their voltage is, as I don't fancy blowing a camera or flash up. What's the risk associated with trigger/reciever voltages to the camera and flash? Would a high voltage reciever/transmitter kill a camera and flash or only a flash?