Pretty confused on headphone connection. On my previous z270(gigabyte gaming 7) motherboard, it has a separate output marked headphone for which Plug in my headphone. If i plug it into the front line out, there will be no sound. On my current z370(gigabyte z370 gaming7), there is no separate headphone out. The manual says plug either a headphone or speaker into the front line out and it did work well for Hd800 headphone. why is that so? My understanding is that line out means not powered.