Magnax - joint venture between Japanese Konica (Konishiroku Photo Industry Co., Ltd.) and American Ampex. Cooperation between the companies began in 1979, in 1980 a joint venture company Konishiroku Ampex Co., Ltd. was created, in early 1981 cassettes were produced from Ampex materials, at the end of the year a Japanese factory began operating. In 1983, Ampex decided to exit the consumer magnetic tape business. Konishiroku Ampex terminated the joint venture agreement with Ampex, again becoming a subsidiary of Konishiroku Photo Industry, and changed its name to Konica Magnetics Co., Ltd. Since then, audio cassettes have been produced only under the Konica brand.

Image Brand Manufacturer Model Description Type Length Year Made in Market
Compact Cassette Magnax GM-I 50 "Grand Master I" Type I Normal 1982 Japan Magnax Konika / Konishiroku GM-I Grand Master I Type I Normal 50 1982 Japan Japan
Compact Cassette Magnax GM-I 60 "Grand Master I" Type I Normal 1982 Japan Magnax Konika / Konishiroku GM-I Grand Master I Type I Normal 60 1982 Japan Japan
Compact Cassette Magnax GM-I 90 "Grand Master I" Type I Normal 1982 Japan Magnax Konika / Konishiroku GM-I Grand Master I Type I Normal 90 1982 Japan Japan
3 pack Magnax GM-I 50 "Grand Master I" Type I Normal 1982 Japan Magnax Konika / Konishiroku GM-I Grand Master I Type I Normal 50 1982 Japan Japan
2 pack Magnax GM-I 50 "Grand Master I" Type I Normal 1982 Japan Magnax Konika / Konishiroku GM-I Grand Master I Type I Normal 50 1982 Japan Japan
2 pack Magnax GM-I 90 "Grand Master I" Type I Normal 1982 Japan Magnax Konika / Konishiroku GM-I Grand Master I Type I Normal 90 1982 Japan Japan