Hi! I have a sony headunit with only 1 rca sub-out. this is already connected to a amp running a sub. i recently purchased a second amp to power the 4 speakers in the car. How can i connect the second amp with only 1 rca output?
Your first amp should have 2 slots for RCA's (INPUT & OUTPUT), the RCA from the head unit goes in the input on the first amp. From the first amp plug some RCA's in the OUTPUT and run that to the RCA input on the second amp.