I think that's what my problem is. I had a Sony CDXC90 installed with a rockford 600a5 amp and every time I fade it to the rear the music will cut off. But if I fade it to the front it will stay on. If all SVT's come with an externeal amp already then maybe it still giving power to the speakers along with the Rockford amp. I don't know but I want to get to the bottom of it.