Sager NP9150 audio buzzing issue not fixed by external sound card

I have a Sager NP9150 that has an awful buzzing audio issue. I can't hear it when I use headphones or the speakers, but when I plug the laptop into my external (amplified) speakers or my mixer/amplifier system, I can notice an annoying buzzing/crackling sound. It's not at all related to system volume and happens even when the volume is at 0 and muted. It also seems to be related to GPU activity since it gets louder and makes other squeaks and clicks whenever anything is happening on screen.

I saw some posts about similar laptops that said this was an issue with an unshielded audio card and interference from other components in the laptop. The cure-all for this problem seemed to be buying an external sound card, which made sense to me. However, I just plugged in a USB sound card (in particular, the StarTech ICUSBAUDIOB) and got the exact same buzzing sound. I am at a complete loss at how this could happen - I can see the sound card sitting on my desk inches away from the laptop but still I can hear the same interference static.

Does anyone have any idea how I can resolve this issue?

 

It seems that there is something wrong with the cable that you use to connect the laptop to your amplifier. Try changing the cable.

 

I should have said, I have tried swapping out every single part in the system except the laptop, and have verified that it is indeed the laptop which is producing the buzzing. I tried swapping the cable, tried hooking up directly to amplified speakers or through my mixing system and to headphones. The same buzzing is there. I have two other laptops and two desktops wired through this system and don't experience any buzzing from those machines. Also the buzzing sound is distinctly related to activity on the laptop, such as moving the mouse on screen or having an animation running.

 

sounds like maybe a ground loop?

try unplugging the power brick from the notebook see if that helps.

 

EDIT: I re-read the post, so it cant be the motherboard at fault.

So you are using some PA sound equipment trough the stereo analog jack, if I understand correctly.
Its from the cables, you need balanced cables to avoid crackling static noises.

Try with a better cable, something BALANCED, like this:


DONT USE RCA JACKS ON PA EQUIPMENT! They are just awful and cannot be balanced (there is no third cable on them).

 

Wow, you're exactly right. It looks like a ground loop is my problem. The guy in this video describes exactly what I'm experiencing. I'm using balanced 1/8" TRS -> 2x 1/4" TS cables but I guess that's not enough. Looks like I'll be buying one of these.

Thanks to everyone for the help.

 

I've experienced similar problems with my NP9150. I resolved the problem by plugging the laptop to a different wall outlet than the one that the speakers are on. So depending on how your place is wired, you might not need to buy anything else.

 

The HUM destroyer is a good option, solves any potential issues when you travel with your PA system and laptop.

 

You can test if that is the issue by totally unplugging the AC adapter and running off the battery.