Z97 Fatal1ty Killer loud humming on audio

ryann wrote: I just upgraded to this motherboard in November and the hum on the audio output is driving me crazy. The much older mobo didn't have this problem and the only new components are this mobo, RAM and processor. The hum in the speakers persists and is most noticeable, even when the PC is off. It goes away only if I unplug the PC power cord or unplug the speakers from the PC. It doesn't vary with PC volume. There is no hum on the speakers when plugged into another source. The power supply is a thermaltake (TR2 RX) 750W bronze, so it's decent, and as I said, my old Mobo didn't have this problem.

Your description sounds (sorry...) like an AC ground loop problem. The hum does not change with volume identifies that type of hum.

Your new and old boards seem to have different ground connections. Your new board has more isolated audio connections, and uses a different ground connection for the audio components than the rest of the board.

Your "speakers" are the only description of the audio system connected to the board, so I'll assume that are simply powered speakers connected to the board.

Are the AC power cords for the PC and the speakers connected to the same outlet or power strip? Does the power cord to the speaker amplifiers have a three connection plug? I assume your PC's power cable has a three connector plug. Did you ever test that the AC wall outlets have their ground connection correctly connected?


I had to attach a wire to the case of a cable TV box that only had a two connector AC power cord, to act as a ground connection to prevent the kind of hum you described.

Do you know if the third/ground connection on your wall outlet(s) are connected correctly?

Did you try a different audio cable between the PC and speakers/amplifier? Is the hum in all the speakers, or possibly just in the sub woofer, if you have one?