Shared knowledge from other DJs
Christian Tobler & Monika Diaz (German)
Jens-Ingo Brodesser

Age Akkerman
Lost in History: the Keys of Tango Music
Hlynur Helgason
Frank Jin
El Espejero
Tango Notes on Argentine Tango Music

An introduction to computer audio
A list of reviewed DACs and forum
Lots of information concerning audio technology by mastering engineer Bob Katz
About the audio file formats
Glossary of terms for sound and audio engineering (German)
Test your audio equipment and your ears
Listener training by Harman International

Data sources and online music shops
Big database for different kind of Tango stuff (mainly music)
Database and onlineshop