Is there or would there be any benefit to installing PAC SIN-35 high level to RCA adapters? I'm currently running an RF PBR300x4 using high level inputs. I'm going to a SoundStream 4.520 with 6 speakers (4 Polk DXi650 wired in parallel and 2 Polk DXi690) I'm using the four channel output of the stock head unit, just haven't had the fader flashed yet. I was wondering if there would be any benefit to add two PAC SIN-35 to the install or just go back with high level inputs into the SoundStream amp?

 

Not really especially with the SS amp. The main reason to adapt (besides a cleaner signal which is not necessary on these bike installs) would be using 2 channel ouput of radio to 4 channel inputs of amp so that you can "y" those outputs.