What were old audio bootlegs recorded with?

For example, this recording from Osaka '96 has such a great sound quality that it's hard to believe it is actually an audience recording (what it obviously is, but still). As far as I'm aware of, regular cassette recorders are/were not capable of recording anything in this level of clarity and balance:

https://youtu.be/kz5T8NMGrBg

Even for a soundboard, the sound would be great. How is it possible?

Many of the better quality recordings were made with DAT recorders but a lot of the quality comes from the location of the recorder - if you are lucky enough to be in a quiet area then there will naturally be less crowd noise picked up.

Plus Japanese audiences are culturally more quiet and respectful anyway.



Personally my first ever bootleg was recorded with something like this...http://www.ebay.co.uk/itm/AUNA-VINTA...-/311806810934

Seems ridiculous now......

With the Japanese recordings you couldn't help but feel that they had brought full soundstudios into the venue. No idea how they managed to do that, but they've basically always been top notch.