Is this a ground loop problem?

[PieIsAwesome]

Here's the deal.

Randomly got buzzing through speakers in game.

Very subtle with no computer activity.

Increases and becomes obvious with GPU load.

Constant sound, speaker volume level has no effect. Sound occurs even when no sound is being played from comp.

Tried headphones, no buzz.

Tried different speakers, no buzz.

Tried original speakers again and buzzing is either very reduced or not there at all (no more loud buzz with GPU load).


Strange for the buzzing to be affected by GPU activity and to come and and go randomly. I tested the PSU with a multimeter and its completely fine, don't believe there oculd be anything wrong with the rig but want to make sure.

Oh, I recently removed and re-mounted the cooler on the videocard. The GPU is being cooled fine, but is it possible that I screwed up with the ram/mosfet thermal pads and that overheating is somehow related to the interference?

 

[GaryJohnson]

I had that issue with some USB powered speakers that I eliminated by using a USB AC power adapter instead of plugging them into my PC.

 

[mpilchfamily]

Sounds like your gettting EMI from the video card messing with your speakers. The speakers giving you the problem probably aren't very well sheilded. But it sounds like the orignal speakers are. Given the close proximitey of the video card to the audio ports its easy for tyhere to be EMI affecting the speakers. So if the speakers don't have adiquate sheilding then you will get interfearance. Could also be the quality of the amp used byt the speakers.

 

[nineball9]

Originally posted by: mpilchfamily
Sounds like your gettting EMI from the video card messing with your speakers. The speakers giving you the problem probably aren't very well sheilded. But it sounds like the orignal speakers are. Given the close proximitey of the video card to the audio ports its easy for tyhere to be EMI affecting the speakers. So if the speakers don't have adiquate sheilding then you will get interfearance. Could also be the quality of the amp used byt the speakers.

No. Shielded speakers are designed to prevent the speaker's magnetic fields from interfering with other devices, namely CRT's. Physically, shielded cone speakers have a ferrous circular cup- or dish-shaped "shield" which is mounted (usually glued or welded) to the rear of the magnet and the edge of the shield surrounds the edge of the magnet. Other speaker designs use other methods for shielding. E.g., I have shielded planar speakers which have 8 bar magnets inside. They are only about 1/2 inch thick but the entire speaker assembly is enclosed in a steel case.

EMI will not affect speakers directly - it's not an amplified signal. Moreover, with cone speakers, the wire for the speaker coil is inside the magnet which EMI will not penetrate.

In short, speakers are shielded to prevent them from interfering with CRT's and not to prevent external EMI interference. High end audiophile speakers (not PC speakers!) which cost many thousands of dollars are rarely shielded, except for center channel speakers. Go try some Krells or B & W's or whatever brand you prefer and ask if they are shielded!