yes indeed they are....and i am not just saying that because i am a Clarion dealer....lol
i personally have a S400 on one vechicle with added on R/S module for the last 5 years and recently put a SR9000 on my other with zero issues
1st check your ground
2nd check voltage on the (+) term of the amp as well as the voltage on the remote wire
3rd check signal voltage coming from the head unit or whatever feeds the 500/1 on the rca cables
I am an authorized direct dealer for Memphis, Clarion, Kenwood, Sony, Pioneer & Kinetik
I can also get several other lines through various distributors