mp3blaster apparently can't handle output to an original Sound Blaster
The sound is badly distorted with loud pops and whistles.

Granted, this is old hardware, but it should behave more gracefully than
this if its not compatable with the hardware, or better yet, it should
add support for playback on this card.

Have you tried different players, with the same audio file, if
possible?

There is no specific support for soundcards on mp3blaster; it relies
on the kernel support.

Maybe you should try to get 2.4.12-ac2, or ALSA, and see if there is a
difference.