Just got the stock 2.6GHz model and noticed coil whine while the system is booting, and when clicking buttons in System Preferences. This is after the Catalina 10.15.1 Supplemental Update was applied which specifically addresses issues with this model.
I don't have time at the moment to investigate further, but will report back in the coming days as I put the machine through its paces. I may also try switching the outlet plug to a 3-prong grounded model to see if that helps.
Attached is a 30 second clip taken from my iPhone 6S Plus. I placed it directly on top of the left speaker grille, and pressed the power button to start booting. Rename the extension from .pdf to .m4a to listen as I can't attach m4a's directly for some reason.
I don't have time at the moment to investigate further, but will report back in the coming days as I put the machine through its paces. I may also try switching the outlet plug to a 3-prong grounded model to see if that helps.
Attached is a 30 second clip taken from my iPhone 6S Plus. I placed it directly on top of the left speaker grille, and pressed the power button to start booting. Rename the extension from .pdf to .m4a to listen as I can't attach m4a's directly for some reason.