The SoundCracker is still on the AmiNet: http://aminet.net/package/mus/misc/SoundCracker

However it is a bad OS hack and has difficulties with AGA and RTG.

I've never told anyone before: There is a secret mode by pressing "left-alt right-alt S". It then uses an internal PowerPacker unpacker, and is also able to play TFMX tunes.