Misteriously ive found that when i use mpg321 it works with the headphones!!! But none of the controls in alsamixer worked with this sound. It seems that it is working through /dev/dsp0 but i dont know if it is the audio card or the headphone jack directly(is it possible? i doubt it). Ive tried /dev/dsp1 and 2 but no results. I dont know how can i go forward with this trouble. Thanks for your time Saladino