On a recent post, there were a lot of comments, which said that they were missing the headphones on newer mobile devices.
How many actually use the headphone jack?
I ask, because I have one on my phone, since I really wanted one, but I rarely use it. Like Tops 1/Month.
To fix the whine buy a ground loop isolator for less than $10 (they’re all the same). It will sit in-line on the input cord.
Basically your phone is getting two paths to ground - the power connection and the headphone jack. This causes interference (the whine). It’s also not good for the power control systems in the phone, though I think it would take years of being connected to actually damage it.