Atoto head unit and stock amp

[JackWade]

Hey all,
I picked up a 2006 vibe with an Atoto touch screen car play head unit and stock amp. Sounds great but 3 months later I’m noticing a hiss in the front right speaker. Turns off 2 seconds after stereo turns off. I didn’t notice it before. May have started after replacing the battery. Do I need to turn off a pre-amp setting or set amp to a certain MHz? I saw a post saying 160mhz. It’s very loud even at volume level 2. There’s also an auto and manual setting. Thanks!