Noise problem with via8237
 

I have a via 8237 built-in soundcard; when I listen to any kind of sound file with any player (XMMS,Mplayer,XINE,Amarok...) the output is disturbed by background noise that persist with any volume.
I tried to turn down to zero Volume of all other channels but does not worked.
I tried to change alsa version, distribution and sound option of kernel, but nothing.
I tried to change options of alsa module about channels but none option value worked.

If someone has a good idea tell me it.

Thanks