Is this noise from my hard drive?

[alexpigment]

I've been putting up with something for years and it just now hit me that I should probably investigate this. When I play anything high-ish gain through my amp and get near my computer, I hear a noise coming through my pickups. This is most problematic when recording (hence why I'm posting here), but this is by no means limited to just recording - it happens through my amp as well. The odd thing is that when I'm clicking around folders on my computer, it stops momentary. Additionally, the noise changes while dragging something around on the screen. Loading applications also causes it to pause. Anyway, here's the noise:

http://www.theselectedworks.com/music/noise.mp3

Is this my hard drive? The only reason I ask is that the hard drive would be accessing data when I'm clicking on folders and loading programs. The other possibility is the CPU itself, I guess. Turning my monitor off has no effect, though the noise does pause momentarily when turning it on/off.

[64Strat]

it's rfi from the cpu and other high speed switching devices like in the power supply.

separation distance helps.... also you could put an earth grounded Faraday cage around the the pc case.

[jefrs]

Pickups.

These coils are absolutely wonderful for picking-up all and any electromagnetic radiation, this is what they do best, it's how they work.

Do not play near any transformers, electric motors, fluorescent lighting (incl the new energy-saver bulbs), anything spitting out RF. The computer is probably creating an eddy current in its case. Shielding is futile, it can act as an aerial.

Short of re-designing the computer to break the dielectric coupling betwixt motors, transformers and chassis, there's not much that can be done. Move away, the inverse-square law applies (if it is 1 at 1d then it is 1/4 at 2d and 1/9 at 3d...). However most guitar amps will benefit by raising the transformers off the chassis on a sheet of Paxolin (PCB), the bolts still keep the frames earthed. Better still use an aluminium chassis.