I recently replaced my head unit with a touchscreen one. It worked great for a while but then it sounded like my rear speakers were going out. The following day all audio stopped except for the front driver speaker. NO sound out of any of the others. Ive checked the cables and fuses and all seems to be ok unless i am missing something. any help would be appreciated.

Ive been told by several people that it may be the amp. Does anyone know a good comparable amp that is not oem i could purchase to replace it. I can install it just not up to date on car audio