Soundmax soundcard cracks&pops

[dubolik]

Hi!
Recently my z60m sound card started to act strange, that is - when I listen to music, and turn up the windows/winamp volume fader all the way up, it starts to distort the sound, or better yet - it starts to make sound like tremolo/chopping effect. The same is happening when I use volume control knobs on laptop.When I lower the volume for two clicks doun the sound gets ok..weird
Does anybody have any idea?maybe it's hardware issue? Thanx!