ok here is the thing my pc is set up to a mixer and am getting noise from the cpu you can here it with head phones and pc speakers when loud even if the sound is on mute. i have found the source using a mic from my karaoke buy holding the mic near things like a transformer (50hz humm) then went round the inside of my pc like were the pcu is and was surprised how clean the signal was but there was some sound of what i had herd some were close.
then i moved to the cpu and omg there it was loud and clear the same sound am getting in my head phones and pa set up the cpu heat sink is acting like a transmitter and bleeding in to the mainboard sound card
so can i put an earth clamp from case to my heat sink or will something blow if i do ?????.....
I would not advice grounding your heatsink lol.
Disable your onboard audio in bios and see if you can still hear it, dedicated audio card would be good too to see if there is something with your integrated sound
lol i thought of that and i do have two sound cards and both still pick it up i have how ever taken the optical out put and am running a decoder to the mixer but any cable running past the heat sink is picking up the signal i had thought of building a faraday cage round the heat sink but don't want to compromise air flow
the sound is not mechanical the heat sink can be used fanless and have tested with no fans on the system i wish i could post a sound clip may be i will try to post a video on youtube if i can cet a cam from some were
I had the same problem after installing new PC in my studio. The noise was really driving me crazy, especially when I connect guitar amps to usb audio interface Edirol UA-1000. I like to combine some vst plugins with analog effects and amps and record it all by mic but this noise was not standable at all, mics are picking it up like crazy... I spent 4-5 days reading about ground loops and trying to fix this but only thing that worked was grounding CPU cooler. This thread was where I got the idea on doing it in a first place, so thank you, it works, you should try it yourself There is absolutely no risk doing this, I also read that this can improve OC stability a bit.
To double-check that you have this exact problem try changing CPU frequency up or down, you should notice noice pitch changing.