LOC issue
 

I was wondering if anyone can give me some suggestions on this problem. I have an amp that doesn't seem to want to take a line out converter signal. When tested on the bench, the amp will take RCA inputs no problem. However, when a LOC is connected the amp will go into protection. The LOC is working fine as it has been tested with other amps... I've also tested three other LOC and get the same results. I need the LOC to work because the car this amp will be going into is keeping the factory radio. Any suggestions? How is a LOC signal any different than an RCA?