04.09.2022, 21:04
(Dieser Beitrag wurde zuletzt bearbeitet: 04.09.2022, 21:07 von Kirunavaara.)
The information on the Vintagecassettes site about which year cassettes were introduced is in many cases only a rough estimation. We would need to do some research in contemporary literature, like ads and articles in Billboard magazines on Google Books, or tape tests - you can find some from the 1970's here: https://audiochrome.blogspot.com/2020/02...views.html
According to Tapehead member "Wilhelm" who worked for BASF's US factory, 3M were first with a cobalt doped ferric, sold as Scotch High Energy, in the early 70's. He also mentioned that the technique was not yet enough refined, recordings would lose some of their high frequencies with every play due to magnetostrictive effects caused by the mechanical pressure between capstan and pinch roller, always breaking some of the oxide particles. 3M temporarily abandoned cobalt doping, they would not return to it before the Master II cassette in about 1977. Second generation Scotch High Energy from ca 1974 onwards is of a lighter brown colour than the first generation, which is a hint on the absence of cobalt.
The Audio Magnetics "Cobalt Cassette" is a strange thing. Its j-card fits into the early 70's line-up, but some details on it look younger. I can find very little information about that model. One thing is for sure: Its quality is far below the early Scotch High Energy, and the colour and surface are different: AM Cobalt is greyish-dull, and Scotch HE is dark brown and more shiny. These are two completely different tapes.
Cobalt doping was not limited to one company only. Besides 3M, at least various Japanese tape makers were experimenting with it, but they waited until they got the formulation stable enough so it wouldn't degrade too quickly from pulling it through a tape deck :-) First out in 1975 were TDK (SA) and Maxell (UD-XL), Fujifilm was about to follow soon (Range-4x and FX-II), Sony was late (JHF and CD-alpha in 1979) because they had direct access to CrO2 from Du Pont. In the US, all the big players (3M, Ampex, Memorex, Audio Magnetics and even Certron) had their own cobalt doped type II tapes by the end of the 70's. The Koreans followed by the early 80's. BASF started making the cobalt doped ferro super LH I in late 1977, but bobalt doped type II not before 1987.
Regards
Martin
According to Tapehead member "Wilhelm" who worked for BASF's US factory, 3M were first with a cobalt doped ferric, sold as Scotch High Energy, in the early 70's. He also mentioned that the technique was not yet enough refined, recordings would lose some of their high frequencies with every play due to magnetostrictive effects caused by the mechanical pressure between capstan and pinch roller, always breaking some of the oxide particles. 3M temporarily abandoned cobalt doping, they would not return to it before the Master II cassette in about 1977. Second generation Scotch High Energy from ca 1974 onwards is of a lighter brown colour than the first generation, which is a hint on the absence of cobalt.
The Audio Magnetics "Cobalt Cassette" is a strange thing. Its j-card fits into the early 70's line-up, but some details on it look younger. I can find very little information about that model. One thing is for sure: Its quality is far below the early Scotch High Energy, and the colour and surface are different: AM Cobalt is greyish-dull, and Scotch HE is dark brown and more shiny. These are two completely different tapes.
Cobalt doping was not limited to one company only. Besides 3M, at least various Japanese tape makers were experimenting with it, but they waited until they got the formulation stable enough so it wouldn't degrade too quickly from pulling it through a tape deck :-) First out in 1975 were TDK (SA) and Maxell (UD-XL), Fujifilm was about to follow soon (Range-4x and FX-II), Sony was late (JHF and CD-alpha in 1979) because they had direct access to CrO2 from Du Pont. In the US, all the big players (3M, Ampex, Memorex, Audio Magnetics and even Certron) had their own cobalt doped type II tapes by the end of the 70's. The Koreans followed by the early 80's. BASF started making the cobalt doped ferro super LH I in late 1977, but bobalt doped type II not before 1987.
Regards
Martin