I am getting terrible sound interference from my desktop PC.
The setup I have is an Alesis i/o2 external USB soundcard with Prodipe active monitors & woofer.
However - I have also tried it direct out from on-board card through jack output. It is the same. Unbearably loud.
It is also prone to picking up outside interference too from phone etc.
I have experimented with moving the speakers and all associated cabling several metres away from the computer and peripherals, but it makes no difference.  
 
I have tried it with my laptop - both USB and internal and there is NO interference. So it IS the computer. Not the sound equipment.
 
Does anyone have any suggestions?
Advice really appreciated as I use the computer for my home music.
 
This is my computer spec
 
CPU Type    OctalCore AMD FX-8350, 4100 MHz (20.5 x 200)
Motherboard Name    Gigabyte GA-78LMT-USB3 v5  (1 PCI, 1 PCI-E x1, 1 PCI-E x16, 4 DDR3 DIMM, Audio, Video, Gigabit LAN)
 
 
Cheers
 
Nick

First step in troubleshooting would be to go into your Playback and Recording devices and turn off all of them that you don't use.
If the weird sound persists, try turning off every other device one by one (obviously not your main listening device) to see if any of those are causing the problem.

Thanks for the advice Greq
I have tried disabling any sound related devices in device manager.
Also removed anything but usb card in Control Panel.
I still get interference.
 
Are you also suggesting I go to device manager and one by one disable other system devices?
If so, are there some that I should leave alone - I don't want to make the computer malfunction!
 
Nick

nottnick said:

 
Are you also suggesting I go to device manager and one by one disable other system devices?

Click to expand...

No no, that shouldn't have anything to do with it.
 
So now we know it's most likely either a hardware problem, or a problem with your primary sound device.

So, it's a start, thanks
 
In summary 
It is not the Alesis as I get the interference using the jack out on the motherboard.
It is not the jack out on the motherboard as I get the interference using the USB Alesis.
It is not the Prodipe monitors as it only happens when they are connected to the switched on computer.
 
I get NO interference when I connect to my laptop.
 
Hmmm.........
 
Help 

Cogitating on my last response I had an idea...
Laptop on was running on battery.
Plugged laptop into mains - interference started.
 
So, I know what the problem is now.
The thing is, how on earth do I fix it?
Everything is running off the same mains plug.
 
Suggestions?
 
Nick

Either try out another laptop power supply, maybe you have a friend with a laptop, just try the supply out and see if the problem persists.

Otherwise you may have to invest in a power supply 'filter' that essentially cleans the mains electricity of noise. 

Looks like a power supply filter then as it is not the laptop that is the problem but the PC.
Thanks I'll look into it.
Nick

Ordered a DAP ELI-101 stereo hum eliminator
 
http://www.highlite.nl/Shop/Products/Audio/Audio-Processing/Analogue-Processing/ELI-101
 
Looks like it will do the job.
Thanks for advice
Nick

Hope it works out.