I have a straight connection from the sound card (green headphone jack) on my computer to the phono (red & white) input on an amplifier. The cable is stereo to phono (1.5m long). When I have the volume low on the pc and turn up the volume on the amp I get a really bad buzzing sound on my speakers, espically the center speaker (I've a 5.1 setup). When I play music on the pc this noise is very bad. I get this noise both from the onboard and PCI sound cards. This is no conflict of sound cards on the pc as this occurred before I instlled the new sound card. I also tried a different stereo to phono cable but the noise is still there. Any suggestions on the cause of this noise or how to eliminate it?