Dating all the way back to the beginning of the chip music scene, artists shared their source files because that was the only way they could get their music out there. This in turn created openness and allowed other artists to learn from the methods of other talented musicians. The net result was better music.
Today, in the days of .MP3 and affordable bandwidth for all, source files have become an afterthought and very few people share them, if at all.
LSDSNG Swap is a common location where 8bit chip musicians can get together and swap source files. By registering and sharing a song of your own, you in turn will gain access to all other source files uploaded to this site.
via Songs | LSDSNG Swap.