05 Yukon Alt Whine in Radio
 

Picked up a nice 05 Yukon but, as we know gremlins are out there. Having Alt whine through the radio through the rpm range. It has the Bose Amp and I am about to pull the console to check the grounds. Had the Alt checked and they said it was ok. Anyone ran into this and fixed it without just adding a filter?

Thanks,

Smitty