Feedback problem, grounding issue?

[techz]

Hey, Please help me sort out this problem.

Today i went out and bought a stereo to 2x mono adapter and connected it to my pc, and I think I've unearthed a grounding problem or something.
When I have the headphones and the creative sub/speaker system connected to the adapter I get a low humming noise, even when the pc is turned off!
I can even get this noise by taking the adapter when the speakers are connected and physically touching the end of the adapter and my pc, I dont even have to touch the pc just go somewhat close to it.
The headphones dont seem to get the feedback at all in either socket of the adapter.
So this only happens to the creative sub speaker system and not the headphones I'm not sure what this means. What I do know is this doesent happen when the creative system is plugged in directly or when its plugged into another adapter I have which is a stereo to 2x stereo adapter. Could this be a crappy adapter or do stereo to mono adapters complete some sort of internal circuit which may be unearthing a grunding problem somewhere?
I dont know much about this field of computing forgive me for any stupid presumptions
Any help would be greatly appreciated, I want to get mixing
thanks in advance
will

 

[CCT]

Most powered speakers do not have an orientation plug, ie, 1 large and one smaller electrical wall socket connector.

Try connecting that the other way round.

 

[techz]

Hey CCT,
I'm slightly confused by that sorry do you mean the power plug?
If you do I live in UK we have 3 pins you cannot change the orientation of the plug?
Please advise
thanks
will

 

[CCT]

In Canada we have 3 hole sockets (power, return and ground) but can have 2 or 3 pin plugs.

However, it does sound like a harmonics interference\grounding issue if it can make the hum while disconnected from the PC.

 

[techz]

How would I go about resolving this? how do I pin down the source of the interference, could it be related to my PC case?
anything I can do in any way?

 

[CCT]

Good place to start is be specific about the motherboard, the adapter and the speakers you are using so people can research\link.

gl

 

[techz]

motherboard is an abit an7 with the onboard sound disabled, the adapter is a simple stereo to 2x mono adapter, w w w .maplin.co.uk/Module.aspx?ModuleNo=1215&&source=14&doy=26m8#features < that one exactly. The sub/speaker system is a creative inspire t3030. All basic stuff pc hardware, nothing fancy.

(wont let me post links until 5 post count).

 

[CCT]

After reviewing the devices and your comments I think the adapter is defective.

 

[techz]

after some quick extensive testing I agree, seems like the adapter isent insulating the connector properly, although it does for the headphones, which explains why it doesent happen with the headphones, might be something slightly different with the design of the connector it does appear to be different, the rings are placed differently.

Thanks for your help, ill try using two sound cards instead.

appreciate it
will