Hi 1audio and thanks for your reply.
Here we go with specs:
Mobo is VIA EPIA M 10000, (C3 1gHz, CLE266 North Bridge, VT8235M South Bridge, 512 MB Ram).
MD is set to have "Standard sound card" and "Stereo" audio setting. Driver is snd_via82xx shipped with Kubuntu.
Alsamixer is ok, meaning that I already opened it and reduced all relevant level, with no effect on my issue.
We are not talking anyway about distortion. sound comes out with very clear chunks even at high volume interrupted by (I don't know the tech word to explain ..) some "bumps"
I don't understand what you mean by "What else is running on the box". It is a standard MD, with UI1 interface and is used only for audio/video playback.
If I go to KDE desktop and try to play any system sound I can notice the same problem. Also tried to play some mp3 with amarok, with same result. So it is not something related to xine itself, but something more general.
I know that VIA can sound very good, mine actually used to play a very clear sound under Pluto.
If you need some more details just drop a line.
Thanks again and regards
Marco