Tagged: magnetic

Metal tape Microcassette (1981 – mid-1980s)

The Microcassette was introduced in 1969 by Olympus for dictation purposes, but in 1981 and 1982 several devices were introduced that used the Microcassette for music recording and playback.

Several personal stereo devices, similar to the Sony Walkman were introduced, such as the Olympus SR-11, and there were also several Microcassette decks for Hi-Fi separates systems from brands such as JVC, Sanyo, Technics and Sony.

The Microcassette for music was a little different to the standard Microcassette and used metal tape (coated with pure metal particles rather than oxide) which had been introduced for the Compact Cassette in 1979 as this offered higher sound quality. Many of the new Microcassette music devices offered Dolby noise reduction, and of course this version of the Microcassette offered stereo sound.

A few pre-recorded tapes were released (mostly in Japan), but the format failed to take off and seems to have disappeared fairly quickly. Even at the time the tapes had limited availability and were expensive, and it’s now hard to find original metal tape Microcassettes.

Despite being used for music playback in its metal-tape form, the cassette seen in the 1971 film ‘A Clockwork Orange’ was the similar Mini-Cassette format and not a Microcassette.

Sources / Resources

Grundig Stenorette (1954 – 1970s)

The Stenorette was an office dictation machine introduced by Grundig in 1954, and successfully sold internationally. It was perhaps the earliest magnetic tape dictation system – at the time of its introduction, most office dictation systems were using discs or belts onto which grooves were pressed, such as the SoundScriber, Audograph, or Dictabelt systems. The first model, the Stenorette A, was nicknamed the ‘tree frog’ due to its green colour. Like some other dictation systems, the microphone doubled as the speaker, and contained stop/start controls.

The Stenorette cassette contained a single reel of ¼-inch tape, and a loop on the end was pulled out and clipped into the take-up reel. Recording time was 30 minutes per cassette, but some offered 45 minutes. Some tapes, particularly those from the US, seem to have no cover and are simply a small reel.

The Stenorette cassette system lasted into the 1970s with the introduction of the Stenorette SL model in 1972, but Grundig launched its first machine using its new cassette format, the Steno-Cassette in the same year. The Steno-Cassette was a true cassette containing dual reels and as well as being more compact, didn’t need to be rewound before being removed from the machine. The Stenorette name was continued on machines using the newer Steno-Cassette format.

Sources / Resources

DASH (Digital Audio Stationary Head) (1982 – mid-1990s)

Sony introduced the DASH (Digital Audio Stationary Head) in 1982 for use in professional recording studios. The DASH system could record two-channel audio on ¼-inch tape, or 24 or 48 tracks onto ½-inch tape, and DASH recorders were produced by Sony, Studer and TASCAM.

The tape itself looked identical to standard NAB open reel analogue tape, but tape for use in DASH and the competing (and incompatible) ProDigi format systems used metal-particle tape which was not suitable for use in analogue systems due to the faster wear on the heads. Several companies produced open reel metal-particle tape for digital audio systems, and some examples included 3M Scotch 275, Ampex 467, EMTEC 931 and Sony own-brand tape. Metal-particle tape was even more expensive than oxide-based tape for analogue systems.

Unlike some other digital audio recording systems using tape such as DAT or U-Matic which used helical scanning, the DASH and ProDigi systems used a stationary recording head.

The audio was encoded as PCM, and included error correction, and all DASH recorders were capable of using 16-bit resolution with a 44.1 or 48 kHz sampling rate, with a couple of models capable of 24-bit 48 kHz operation.

DASH and ProDigi were the two main open-reel digital audio recording systems in use from the early-1980s to the mid-1990s, but eventually the falling price of hard-disk space, as well as more compact systems such as ADAT, made them less viable.

Although DASH was a digital system, it still had the disadvantage of having to wind through the tape to find a particular point, and wear could still be a problem. Poorly maintained machines or tape, dust, or fingerprints could render tapes unusable despite the error correction system.

Sources / Resources

Preservation / Migration

media stability 5obsolescence 5

Dictaphone Dictet (1957 – early 1960s)

The Dictaphone Dictet was a portable dictation device introduced by the Dictaphone Corporation in 1957. It was perhaps the earliest portable magnetic tape dictation system – the Grundig Stenorette was an office dictation system using tape, introduced in 1954. An earlier portable system, the Protona Minifon used wire recording.

The Dictet was fully transistorised and weighed 1.2kg. The cassette had a metal shell and could record up to 60 minutes (30 minutes per side) on ¼-inch tape that ran at 2½ inches per second. Using special mercury batteries, the Dictet could operate for 20 hours.

The Dictet lasted until at least 1962, but it is unclear how much longer it lasted against newer competitors such as the Compact Cassette of 1963.

Sources / Resources

Philips EL 3581 (1958 – early 1960s)

The Philips EL 3851 was an office dictation machine introduced by Philips (known as Norelco in the US) in 1958 and was one of the earliest magnetic tape dictation systems (the Dictaphone Dictet was launched shortly before it). At the time of its introduction, most dictation systems were using discs or belts onto which grooves were pressed, such as the Dictabelt, SoundScriber and Audograph systems.

Although the EL 3851 uses a cartridge so no threading is required, the tape is housed on two separate 3-inch reels with ¼-inch tape and cine spindle holes suitable for domestic open reel tape recorders. Removing a clip from the cartridge shell allows the reels to be removed.

Like some other dictation machines, the microphone also doubles as a speaker, and contains some tape controls. A foot pedal and external speaker were also available.

Philips later introduced the much smaller Compact Cassette format in 1963, followed by the mini-cassette in 1967 and it doesn’t appear the EL 3851 was produced for long.

Sources / Resources

MPEG IMX (2001 – 2016)

MPEG IMX (also known as D10) was a standard-definition digital video cassette format introduced by Sony in 2001 and was part of the Betacam family of professional video formats. It was priced between Sony’s Betacam SX and the more expensive Digital Betacam, and was intended to compete with the Panasonic DVCPRO 50 system. As the name suggests, MPEG IMX recorded in MPEG video format, in case MPEG-2 using only I-frames and 8 channel audio.

Like other Betacam formats, tape width was ½ inch and cassettes were available in small or large form factors, with the S size holding up to 60 minutes of video, and the L size up to 184 minutes. To distinguish MPEG IMX tapes from other Betacam formats, the shells were coloured green. Metal particle tape was used.

All IMX video recorders could playback Betacam SX tapes, and some could playback Digital Betacam as well as analogue Betacam and Betacam SP tapes, the video from which could be encoded into MPEG-2 format. Only IMX tapes could be used for recording in IMX video recorders.

Like all Betacam formats, no new MPEG IMX video recorders are being made, having been discontinued in 2016.

Sources / Resources

Exatron Stringy Floppy (1978 – 1986)

The Exatron String Floppy was introduced in 1978, and was an endless loop tape cartridge system for microcomputers. At the time, floppy disk systems were still expensive, and cassette tapes were very slow. Despite the name, so-called stringy floppy systems are unrelated to floppy disks.

The tape cartridges, called wafers, contained a 1/16-inch loop of mylar-based chrome dioxide tape, in different lengths according to the capacity of the wafer. The smallest wafer contained 5 feet of tape and could hold 4 KB of data, and the longest was 75 foot and, capable of holding 64 KB of data. A 16 KB file took just 24 seconds to load.

The Exatron Stringy Floppy system was most commonly used with the TRS-80 range of computers, and did not require an expansion interface. By 1982, the price has fallen to $99.50. As well as being used to save data, software, including programs and games, was available on Stringy Floppy wafers.

Although popular with TRS-80 owners, the system could be unreliable, and as the price of faster and more reliable floppy disk drives fell they became less attractive. They continued to be advertised until 1986.

Similar stringy floppy tape systems were available during the 1980s, including the Sinclair ZX Microdrive, and the Rotronics Wafadrive.

Sources / Resources

Minifon wire reel (1959 – 1967)

The Minifon name was applied to a range of miniature wire recorders introduced initially by the German company Monske & Co GmbH in 1951, and then produced by Protona GmbH from 1952 until 1967, although they were also sold under the Telefunken, ITT and EMI brands.

The recorders ran on batteries, and could record over 2 hours on a single reel of wire (later models allowed for 5 hours of recording). As the reels turn, the recording/playback head moved up and down so the wire was spooled evenly on each reel.

They were popular for covert recordings, and an accessory microphone that was made to look like a wristwatch was available. Minifon recorders were sold in overseas markets such as the US and UK.

In 1959 the Minifon Ataché was introduced, using a tape cartridge for the first time, but the wire-based recorders continue to be produced until Protona ceased production of all Minifon models in 1967.

Sources / Resources

HDCAM SR (2003 – 2016)

HDCAM SR (Superior Resolution) was a professional high-definition digital video cassette format, introduced by Sony in 2003 as a higher quality variant of its existing HDCAM system.

Like other Betacam-related formats, HDCAM SR cassettes were available in large and small sizes, and had the same tape lengths as Digital Betacam (up to 40 minutes for S and 124 minutes for L tapes).

It used higher particle density tape allowing an increased bit rate (a choice or 440 or 880 Mbps). Like HDCAM, it was commonly used in high-definition television production.

Sony HDCAM SR tapes were black with a cyan lid and contained a 1K memory chip to store metadata about the tape.

In 2016, Sony announced that it was ceasing production of its remaining ½-inch video tape recorders and players, including those for the HDCAM SR format.

Sources / Resources

HDV (2003 – 2011)

HDV was a high-definition digital video format for camcorders. Because of its high quality, it has been used for broadcast television as well as amateur video recording. JVC was the first company to release a HDV camcorder in 2003, with Sony and Canon producing camcorders later.

HDV video can be recorded at 720p and 1080p, sometimes referred to as HDV1 and HDV2 respectively.

Although special HDV tapes are available, their use was not required as the tape formulation (Metal Evaporate) is the same as standard MiniDV cassettes. One Sony camera could also use the large DV cassette format. HDV devices could usually play and record in DV format as well as HDV.

Accessories were available to allow HDV camcorders to record to non-tape media such as CompactFlash cards.

By 2011, Canon, JVC and Sony had discontinued their HDV products, and invested instead in fully tapeless formats such as XDCAM.

Sources / Resources