So I'm using a ProFX12 for video production (it was free, used one from my uncle who does radio). There's this odd buzzing sound in my audio though. My mic input to mixer is XLR. My mic output is 1/4" Y cable > 1/4" stereo cable > 1/4" to 3.5mm adapter > camera. Here's what I've tried:
1) Switched mics. No change
2) Unplugged all mics. No change.
3) Zeroed out all channels. Muted all channels. No change.
4) Unplugged everything from the mixer except the power and the main output. No change.
5) Unplugged the 3.5mm from the camera. Sound disappears (so its not the camera).
6) Plugged everything back in. Made sure the only thing on the circuit was the mixer. No change.
7) Tried plugging the mixer into other outlets. No change.
8) Detached output and plugged headphones into mixer instead. No change.
9) Tried using tape out intsead of main out. Can't get any audio so i guess tape out doesn't work.
10) Plugged everything into my desktop instead. Buzzing sound is more of a high pitched whine now, that could just be my onboard sound not being very good.
So I think its the mixer, but I can't figure out for the life of me what's wrong. I've seen lots of people with similar problems online but none that exactly match this. Everything points to a ground loop or some other ground problem, but I tried a GFI outlet too, and mad e sure the mixer was the only thing on the circuit. When my uncle got rid of this board, he did so because the #1 XLR input stopped working. He never mentioned anything about noise interference. If you want to know exactly what the sound sounds like I did produce one video you can really hear the sound after 1:55. Prior to that has other, unrelated audio struggles
Anyone know what I'm missing? Is my mixer just broken?