Though now largely forgotten, did the Avilyn magnetic particles represent the absolute zenith of cassette tape advancement?
By: Ringo Bones
This substance has now virtually become an “alien technology” for those born way after the heyday of the cassette tape. But back then, this represented the value-for-money in cassette tape technology terms when it comes to sound quality. Besides the more expensive metal particle tapes, cassette tapes that use Avilyn magnetic particles are probably the closest yet to sounding like professional open-reel tapes. Stranger still, Avilyn magnetic particle technology has its origins way before cassette tapes become a runaway commercial success in the 1980s.
Developed as a high coercive magnetic particle developed for sound and video recording back in 1974, Avilyn is an acicular magnetic iron oxide on whose surface certain cobalt compounds have been adsorbed. The coercive force of the particles is determined by the amount of cobalt and other preparing conditions, and is controllable between 450 and 800 Oe (Oersteds). The particles display much improved thermal stability with respect to remanence and coercive force. The new video tape having a coercive force of 550 Oe is compatible with chromium dioxide video tape in recording characteristic according to measurements on a conventional video tape recorder. The head wear rate of the new Avilyn tape is about one-fifth that of chromium dioxide tape and is almost the same as for conventional iron oxide tape. Tape demagnetization is not as serious as is in the case of cobalt-doped gamma ferric oxide tapes.
During the 1980s, Avilyn was mostly used in TDK’s high-bias Type-II cassette tapes and VHS video tapes. TDK also produces Avilyn open-reel tapes for professional studio recording use at the time when 16-bit digital audio recording technology was still in its infancy. Sadly, during the early part of the 21sr Century as the prices of recordable compact discs and associated equipment came tumbling down and availability increased, everyone’s love affair with the cassette tape slowly waned.