The first copyright law in Argentina covering artistic works went into effect in 1933 (Ley N° 11.723 | english translation). That law allowed either corporations or individuals to hold a copyright on artistic works for 50 years from the year of first publication.
As of 2019, the audio on phonographic records made before 1949 are now in the public domain. Under the previous law, records made before 1959 were in the public domain. (Since the law was changed in 2009, 2008 – 50 years = 1958)
This provision in the modification to law…
Los fonogramas e interpretaciones que se encontraren en el dominio público sin que hubieran transcurrido los plazos de protección previstos en esta ley, volverán automáticamente al dominio privado por el plazo que reste, y los terceros deberán cesar cualquier forma de utilización que hubieran realizado durante el lapso en que estuvieron en el dominio público.
…states that artistic works that were in the public domain under Ley N° 11.723, that are now protected by the modifications of Ley N° 26.570 (Enacted: December 11, 2009) have automatically returned to the private domain until they expire again. Furthermore, the new law states that any third party using works that have returned to the private domain must stop using those works.
- Music recorded in Argentina before September 28, 1933 — Always in the Public Domain.
- Music recorded in Argentina more than 70 years ago — Public Domain.
- Music transferred from original records and republished (CDs, digital files, reprints on vinyl records, or any other audio format) with a claim of a new Phonogram Copyright are not in the Public Domain until 70 years after their publication. For example, the audio on a vinyl record created in 1980 is protected by copyright until 2050 (1980 +70 years), even if the audio on that record is public domain tangos from the 1930’s.
- Music you, or others, copy from original records (78RPM shellacs) that are more than 70 years old, who then share them freely, are in the Public Domain.
The Internet Archive
A source of public domain media is the Internet Archive. To see a list of Argentine Tango music that has been transferred from original 78RPM shellac records, and are in the public domain, check out this advanced search link on the Internet Archive.
UCSB Discography of American Historical Recordings
Another source of public domain media is the University of California at Santa Barbara Discography of American Historical Recordings. While the name of the project does not sound like it would have any Argentine Tango recordings, it appears to contain many Golden Era recordings by Orquestas típicas. These can be found through a variety of searches, such as searching for “Orquesta”, or a more complex search with a data range and location.