So. I recently upgraded my microphone situation from a lapel mic to a proper xlr mic. So I now use the M-Audio M-Track Solo to provide the phantom power and to convert the XLR to USB. Sounds great. The M-Track Solo also has an output so I can monitor the microphone and enable me to hear myself talk so I am not shouting into the mic. So I got a Maker Hart 3 input mixer and run a patch cable from the computer to the mixer and a short patch cable from the mic monitor to the mixer and vola. Except even though the mic monitor is clear the pc audio has a faint whine, like a buzz saw operating. I know it's the PC audio as I turn down the volume it goes away, I swap inputs and it moves over. I unplug the PC patch cable and it goes away. I swapped out the patch cable I bought for the one that came with the one in the Hart box and it doesn't go away. I switch the patch from the rear audio output to the front panel output, it doesn't go away. I plug the headphones into the PC directly it goes away. So everything says it's the patch cable or noise being introduce into the patch cable, well, at this point just noise introduced into the patch cable from the PC that the headphones can handle but the mixer can't. Anyway to make this go away?