Phantom 12Volt cause noise to speakers

[kraka]

EMU APS Audio card. It consists of two pieces connected together with a cable, (inside the PC). One is placed rear and the other (it is like Audio interface) in front. In this (in the front), there is an input (big jack) for a Microphone ,and a button to engage Phantom Power 12 Volt (for condensend mics).
Every time I turn on - engage phantom power, there is a noise coming out of the speakers and this noise also included in any of the recordings I may will do (with the condesend mic). THE NOISE IS THERE, EVEN NO MIC IS PLUGED IN. AND APPEARS ONLY IF I ENGAGED PHANTOM POWER.
Does anybody know what is the couse of this ?
I am thinking that for some reason, the 12 volt power does not only goes into the mic, in order to power it up, but also into the oposite direction, that is to the speakers. and cause this noise .
Thanks for any help.

(additional I want to share something I noticed, maybe useful. Next to the jack for the condesed mic, there are other inputs. One of these, is a digital input. I noticed that this is not grounded. I mean that when I connect it to a ground point, using a multimeter's pins, does not make the "beep" sound indicates the connection (all other inputs outputs making the "beep" sound). So first, I used a small wire and conect it to a ground point, but problem insist. After, I disconected this digital input socket, using a solder iron, but the problem also did not solved...)

 

[Vilpted]

Sheild the cable and get your receiver off the same circuit/fuse as your computer.... I would try my second idea first. It might be that easy. Remember, K.I.S.S.

 

[kraka]

Thanks for your reply.
You are right, because I see that PC and one of the two speakers, share the same socket (from wall). I will try to seperate them. (Now I am far away from home)
Aboute the cable, you mean the microphone's cable ? Is there an easy way to shield it or must I buy a new one that is already shield from electromagnetic noise ?

 

[Vilpted]

Well I don't really know how to make it I do however believe that it's more of wire that goes through like tin foil or something to shield it but what I do know for sure is that someone made it which means it's possible for you to make it as well now the question you should ask yourself is, is the juice worth the squeeze? And I believe your answer will be no. So honestly just **** up and go buy one but before you do I would probably try to switching the I believe it was your audio was making buzzing noise from your PC I don't know pretty much stuff off the same circuit because right now if I'm correct you have a ground loop which I've experienced that as well it happens in kind of well it doesn't really matter what age your house is it just happens electric can cross talk just like network cables, but unlike Network, you aren't dealing with a digital signal so that's where your noise would come from but I'm not like a certified guy or anything so wish you the best man yes or somewhere and you won't learn until you have to deal with it unless you're like older than me and then that's kind of sad but again you guys start somewhere night man