I attempted to install a second amp for the rear speakers.After the install When I turned the power on, the system made a noise as if two wires were crossed. Now the system doesn't come on at all. The system is rated for three separate speaker amps. This was the second amp I was attempting to hook up to 6 x9 rear speakers. My Dual xdvdn8190 is a new system in a 1984 corvette. Does anyone know what might have gone wrong?.