Development of Coated Tape and the Magnetophon in Germany in the 1920s thru 1950s
Altho Oberlin Smith proposed magnetic recording on a wire or a tape, possibly a coated non-magnetic
medium, in 1888, almost all of the magnetic recorders from 1900 to 1946
used a steel wire or tape as the medium. But a steel medium always had
insurmountable problems: it is expensive, heavy, hard to handle, and
hard to splice. Then in 1928 the Austrian Fritz Pfleumer conceived a method for applying a
magnetizable coating to a non-magnetic base. Thus was the beginning of
the modern "tape" and "tape recorder", developed in Germany over the period
1930...1942. The 1940s Magnetophon is the basis for the world-wide development of
magnetic tape and tape recorders beginning in the mid-1940s.
The Magnetophon story is told several places, including on Wikipedia.
Friedrich Engel has told the story of "The Introduction of the
Magnetophon", with illustrations, in "Magnetic Recording, The First 100
Years", edited by Daniel, Mee, and Clark (IEEE Press, 1999).
The technical details of the Magnetophon were given by
Drenner, in 1947,
and more technical details are in the original German-language papers..
It is well-known that ac bias, one of the essential ingredients of
high-fidelity magnetic tape recording, was originally discovered by Carlson and Carpenter in the
US in 1921, then forgotten, then re-discovered independently by three
different inventors, including Weber and Braunmuehl in Germany, around
1938...1941. We have recently found a fourth discovery of ac bias, by Wooldridge
the US around 1938, at Bell Telephone Laboratories (BTL).
Unfortunately, BTL management thought that a high-quality magnetic
recorder would reduce the use of the telephone, so they delayed
publication of Wooldridge's paper until 1946, and even then "hid" the
mention of ac bias in a footnote.
Those who read German should enjoy Friedrich Engel's "Zeitschichten: Magnetbandtechnik als
Kulturträger. Erfinder-Biographien und Erfindungen. Zweite Ausgabe 2010.
Chronologie der Magnetbandtechnik und ... Fernseh-, Musik-, Film- und