Composer Kenji Yamamoto was fired mid-way through Dragon Ball Kai (the 2009 recut) for extensive musical plagiarism. Toei then retroactively replaced his score in DBZ itself for all official home video releases (DVD/Blu-ray) and streaming. The "original" DBZ with Yamamoto's intense, rock-driven synth score became legally unavailable.
If you want to check current status: search archive.org for "Dragon Ball Z" "TV ver." "Japanese audio" and look for items uploaded before 2023. Many still exist, but they're hidden behind "Item cannot be previewed" warnings—though the files remain downloadable. dragon ball z japanese internet archive
Here’s the breakdown of the story:
That is an interesting story, because the "Japanese Internet Archive" angle touches on a major piece of anime preservation history. Composer Kenji Yamamoto was fired mid-way through Dragon
The core of it involves —specifically, the original Yamamoto soundtrack, which was later replaced. If you want to check current status: search archive