I pulled the factory radio and replaced it with a boss head unit. the radio that I pulled was a Hitachi unit and I retained the factory speakers. I'm not sure why, but I have alternator whine in my speakers and have tried all the advice about this issue on you tube to no success. I'm not sure if my car has a factory amp so I'm asking for help. What can I do and is there a amp with this factory radio.

 

This flow chart at the link below might help. Typically the issue is bad grounding.

https://www.crutchfield.com/learn/ca...ose-noise.html