Headphone Jack Line Noise Buzzing and Interference

I'm sitting here in my church sound booth with my laptop connected via the headphone jack to a Mackie 24*4*2 4-Bus mixing console. The jack is a 1/8" stereo jack connected to a y-splitter that inputs the signal into two mono channels 23 and 24, which are shared on the mixer as left and right.

The noise that is being transmitted from the laptop occurs constantly, and changes as the system is used, such as when the hard drive is accessed. It's an unacceptable situation in a live sound environment and it shouldn't be happening.

Has anyone experienced this and if so, what are some of the potential solutions short of lifting the ground on the power strip? I lifted the ground and it the noise is decreased by 90% but it still exists. I can't play live from Reason 4 or any other sound applications.

If I connect an external USB sound card to the laptop, the problem becomes non-existent, but that's not a viable solution for a tool in the $1000.00 range. It should simply work.

Any expert opinions are welcome. Thanks.

 

by the way, the ground lift isn't really the solution, in fact, removing it from AC power eliminates the problem, so we know that when the laptop is charging there is severe interference on the headphone outputs.

Unless someone can point me in the direction of a battery that will last 12 hours at full screen brightness, I'm going to have to write a letter to HP.

 

I also tried removing the battery so it ran on only AC power and the problem persists.

 

have you tried updating the sound drivers?

Also which laptop do you have?

 

I have (had) the exact same problem and it's so annoying! I updated drivers, re-installed drivers and also did a clean Vista install (was gonna do that anyway and hoped for the problem to go away with that) but the same buzzing and crackling interference in the background...
I ended up buying the Creative X-fi Xtreme soundcard and plugged in to the express slot. Now no interference whatsoever, but have had some problems with the software for the Creative soundcard freezing up and also some issues with optimizing the sound. Also the card sits VERY loose in the slot, so Im not completely happy about this solution, in addition to the frustration over having to pay for an external soundcard, because my spanking new laptop has this annoyance. But since I cannot stand listening to that buzzing in the background and have tried updates and re-installations and nothing helped I decided it was the easiest fix for now.
If you google the problem you will find a bunch of other people having the same issue with laptops and on-board soundcards. Let us know how everything goes

 

What models do you have?

I have the same problem with my nx9420.
The noise is only there when the fan is running, and the noise changes if the HDD is working, or if I unplug the power cord.
I've had the same noise with windows 2000, XP, 2003, Vista, 2008 and OS X.
Oh and in BIOS as well, and with the HDD removed.

I opened the laptop to clean the heatsinks, and at the same time I checked the cables to the audio board. I lifted the cables and the board up and away from the HDD, removed the modem board (LOL I just had to try), disconnected various cables inside, but the result was always the same: removing the fan cable was the only way to end the noise.
It's a good thing that it's so easy to disassemble though.

I wonder if a different fan would generate less audio output interference?