Editing Tape bias (section)

=== DC bias ===
The earliest magnetic recording systems simply applied the unadulterated ([[baseband]]) input signal to a recording head, resulting in recordings with poor low-frequency response and high distortion. Within short order, the addition of a suitable direct current to the signal, a DC bias, was found to reduce distortion by operating the tape substantially within its linear-response region.  The principal disadvantage of DC bias was that it left the tape with a net magnetization, which generated significant noise on replay because of the grain of the tape particles.  However: the earlier [[wire recorder]]s were largely immune to the problem due to their high running speed and relatively large wire size. Some early DC-bias systems used a permanent magnet that was placed near the record head.  It had to be swung out of the way for replay.  DC bias was replaced by AC bias but was later re-adopted by some very low-cost [[Compact Cassette|cassette]] recorders.<ref>Steve Beeching. [https://books.google.com/books?id=0xXCNpEhFEMC&pg=PA5 "Video and Camcorder Servicing and Technology"]. 2001. section "Tape bias (audio)". p. 5.</ref><ref>Michael Talbot-Smith. [https://books.google.com/books?id=XOvf30iChsYC&pg=SA3-PA7 "Audio Engineer's Reference Book"]. 2013. section "Linearity improvement with bias". p. 3-7.</ref><ref>Charles G. Westcott. [https://books.google.com/books?id=tRBTAAAAMAAJ "Tape recorders, how they work"]. 1956. p. 83.</ref><ref name="magneto">Peter Hammar and Don Ososke.
[https://www.americanradiohistory.com/Archive-DB-Magazine/80s/DB-1985-09-10.pdf "The Birth of the German Magnetophon Tape Recorder 1928-1945"]. p. 34-35.</ref>