[mva5580]

Having an issue I'm hoping I can get resolved.  
 
So I've got Yamaha HS80M speakers + Yamaha sub hooked up to my PC via an XLR to 3.5mm adapter (I have a Soundblaster Zx) and I've got this hum/buzz that I'm trying to get eliminated. It's not like unbearably horrible or anything....but it's there and I'd like it to go away. I know the PC source is the issue because 1) When I turn off the PC the sound goes away and 2) When I use the same XLR to 3.5mm adapter to go into my turntable preamp, I don't hear it.  I've tried using the onboard sound instead of the Zx, same result.  I have also hooked up the speakers with the same adapter to a laptop I have....no noise.  So it is certainly something involved with that PC. 

Does anyone have suggestions on things I could do to solve this problem? I'm not against changing out my sound card, if need be. 
 
The speakers sound incredible by the way....I mean holy crap.

 

[PurpleAngel]

Guessing you have a ground loop.
Guess there is a signal traveling between the PC's power cable and the Yamaha's power cable.
Are they all plugged into the same surge protector/power strip?
Plug the PC and Yamaha power cables each into separate wall plugs.

 

[mva5580]

They were initially all plugged into the same power strip yes, and I did try moving 1 of the speakers and the sub to a different power strip, but the same thing happened. If I kept 1 speaker in that same strip would it still have the same impact? Or would it potentially go away from the speaker that I moved?

 

[PurpleAngel]

They were initially all plugged into the same power strip yes, and I did try moving 1 of the speakers and the sub to a different power strip, but the same thing happened. If I kept 1 speaker in that same strip would it still have the same impact? Or would it potentially go away from the speaker that I moved?

 
You want to PC's power cord plugged into a socket separate from the both speakers and the sub-woofer power connections.
Like get a separate power strip and plug the power strip into a wall socket away from where the other power strip is plugged into the wall socket.
PC connected on one power strip and the Yamaha's plugged into the other power strip.

 

[mva5580]

Well I did try it with 1 speaker and 1 sub in 1 power strip and the PC in another, and I'm getting the same sound out of the 1 speaker that I have plugged in/turned on.   It's just a long stretch for the left speaker to go to that other power strip, that's why I'm not adding that in for this test.  But with 2 of the 3 plugged into a different strip than the PC....same result.  

 

[mva5580]

So I moved all 3 of the speakers to an outlet across the room via an extension cord/power strip....and problem solved.  Guess the other outlet that was close to the original was on the same "run" or something.  
 
Now I guess I just need to decide what I'm going to do long term to have one hooked up to the outlet closest to the PC, and 1 going long distance to the other outlet.  I haven't tried the speakers on the close outlet and the PC on the distant outlet though, if the buzz is still gone with that I imagine I'll run the PC on an extension cord around the edge of the room.