2 inch Quadruplex (also called 2″ Quad, or just quad, for short) was the first practical and commercially successful videotape format. It was developed and released for the broadcast television industry in 1956 by Ampex, an American company based in Redwood City, California. This format revolutionized television broadcast operations and production, since the only medium available to the TV industry before then was motion picture film used for kinescopes, which was much more costly to utilize, had lower image quality than videotape, and took time to develop as well. Bottom view of VHS videotape cassette with magnetic tape exposed Videotape is a means of recording television pictures and accompanying sound onto magnetic tape as opposed to movie film. ... 1956 (MCMLVI) was a leap year starting on Sunday of the Gregorian calendar. ... Ampex is based in Redwood City, California. ... The skyline of downtown Redwood City Redwood City is the county seat of San Mateo County, California. ... Film refers to the celluloid media on which movies are printed. ... The term kinescope originally referred to a type of early Video camera tube. ...

Since most West Coast network delays done by the TV networks at the time were done with film kinescopes that needed time for developing, the networks wanted a more practical, cost-effective, and quicker way to time-shift programming for later airing in the West Coast (as well as a general production medium that was not as costly or time-consuming to edit and develop as film). These reasons were part of the motivation for designing a video recording technology that used magnetic tape, in this case, the 2 inch Quad.

The format gets its official name of Quadruplex from the fact that it uses 4 heads mounted on a headwheel spinning tranversely (width-wise) across the tape at a rate of 14,400 rpm for NTSC-standard Quad decks, and 15,000 rpm for those using the European PAL video standard. This method was called quadrature scanning (as opposed to the helical scan transport used by later videotape formats). The tape ran at a speed of either 7.5 or 15 inches per second (190 or 380 mm/s), 15.625 inches per second (400 mm/s) PAL, and the audio, control, and cue tracks were recorded in a standard linear fashion on the edges of the tape. The cue track was used either as a second audio track, or for recording cue tones or time code for editing. NTSC is the analog television system in use in Korea, Japan, United States, Canada and certain other places, mostly in the Americas (see map). ... PAL, short for phase-alternating line, phase alternation by line or phase alternation line, is a colour encoding system used in broadcast television systems in large parts of the world. ... Helical scan or striping is a method of recording higher bandwidth signals onto magnetic tape than would otherwise be possible at the same tape speed with fixed heads. ... Timecode is also the title of a 2000 film directed by Mike Figgis which was shot in one continuous take. ...

A typical 4800 foot (1500 m) reel of 2 inch quad tape holds approximately 1 hour of recorded material at 15 inches per second (380 mm/s).

A reel of 2 inch quad videotape compared with a modern-day miniDV videocassette

Each transversely-recorded track of video on a 2 inch Quad videotape holds one-sixteenth of a field of video. In other words, the format used segmented recording. This meant that 2 inch Quad was not capable of "trick-play" functions, such as still, shuttle, and reverse/variable-speed playback. But the format had quite sufficient image quality for broadcast (it produced about 400 lines of video resolution), and remained the de-facto format and industry standard for television broadcasting from its inception in 1956 to the mid-1980s, when newer, smaller, and less high-maintenance videotape formats supplanted the role of 2 inch quad. Image File history File links Download high resolution version (1024x768, 585 KB)A reel of 2 Quadruplex (aka 2 Quad) videotape dating from the mid-1970s, compared with a modern-day miniDV digital videocassette for size comparison. ... Image File history File links Download high resolution version (1024x768, 585 KB)A reel of 2 Quadruplex (aka 2 Quad) videotape dating from the mid-1970s, compared with a modern-day miniDV digital videocassette for size comparison. ... A MiniDV tape Digital Video (DV) is a video format launched in 1996, and, in its smaller tape form factor MiniDV, has since become one of the standards for consumer and semiprofessional video production. ...

There were 3 different variations of 2 inch Quad:

• Low-band, which was the first variety of Quad introduced by Ampex in 1956,
• High-band, which used a wider bandwidth for recording video to the tape, resulting in higher-resolution video from the VTR, and
• Super High-band, which used a pilot tone for better timebase stability, and higher coercivity tape.

Most Quad machines made later in the 60s and 70s by Ampex could playback both low and high-band 2 inch Quad tape. In material science, the Coercivity of a ferromagnetic material is the intensity of the magnetic field required to reduce the magnetization of that material to zero after the magnetization of the sample has reached saturation. ...

The beginning of Quad

At the beginning of the 1950's, several companies along with Ampex, such as Bing Crosby Enterprises (BCE), and RCA were all competing to release a videotape format. RCA and BCE did release working prototypes of their recorders, but their downfall was that they all used a longitudinal (stationary-head) method of recording, much like audio tape recorders. This meant that the tape had to be recorded at a ludicrously high speed (around 120 in/s) in order to record a sufficient amount of bandwidth to reproduce an adequate video image (at least 2-3 MHz for a watchable image), in turn requiring large amounts of tape on large reels used by these early machines from RCA and BCE. In Britain at that time, the BBC developed a similar stationary-head VTR system that saw some on-air use, called VERA (Vision Electronic Recording Apparatus). For other uses, see RCA (disambiguation). ... This article is an overview article about the Crown chartered British Broadcasting Corporation formed in 1927. ... Vera can refer to: Geographical locations: Vera, a town in Oklahoma, United States Vera, a town in Santa Fe, Argentina, head of the Vera Department Vera, a town in Almeria, Spain Works of art: Vera, a novel by Elizabeth von Arnim Vera; or, the Nihilists, a play by Oscar Wilde...

Plus, time-shifting of television programming for the West Coast by the networks at the time (in order to broadcast their programming at the same local time in the East and West Coasts) using film kinescopes was quite a rushed and perilous ordeal. This was due to there being only 3 hours for the West Coast branches of the TV networks to receive video for the programming from the East Coast (live via leased microwave relay or coaxial cable circuits provided from the phone company (AT&T) at the time), and then to record such to film kinescopes, and lastly to develop the film to be aired 3 hours later on the West Coast. This usually meant the kinescope film was aired almost immediately after it came straight out of the developing equipment, still warm from the film dryer used to dry the film prints coming out of the developing chemicals. These were referred to by the networks as "hot kines". According to the History of Tape Recording website, the networks used more raw film stock for kinescope delays for the West Coast than all of the Hollywood film studios combined. They were desperate to obtain a quicker, less expensive, and more practical solution. AT&T Inc. ...

Ampex, seeing the impracticality of the prototype BCE and RCA VTRs, started to develop a more practical videotape format with tape economy in mind, as well as providing a solution to the networks' West Coast delay woes. Starting in 1952, Ampex built the Mark I prototype VTR, using 2 inch wide tape. Ampex decided that instead of having the tape move fast across the head to record enough bandwidth for video, that the head move fast across the tape instead. This resulted in the Mark I using arcuate scanning, which consisted of a spinning disk, where its face (where the heads were mounted) was in contact with the tape (as opposed to the edge of the headwheel with transverse quadrature scanning). This resulted in an arc-shaped track being recorded across the width of the tape. Arcuate scanning resulted in a head-to-tape speed of about 2500 in/s, but problems with timebase stability of the reproduced video signal from the tape led Ampex to abandon arcuate scanning in favor of the more reliable transverse scanning system. 1952 (MCMLII) was a Leap year starting on Tuesday (link will take you to calendar). ...

Ampex soldiered on throughout the mid-50s with the Mark II and Mark III prototype recorders, which now used transverse scanning. The Mark II used FM modulation for recording video to tape, resulting in a much-improved, but still noisy video image (the Mark I used AM modulation), and the Mark III had improved signal-processing and servo electronics, resulting in perfect video being reproduced from the machine. Frequency modulation (FM) is a form of modulation which represents information as variations in the instantaneous frequency of a carrier wave. ... Amplitude modulation (AM) is a form of modulation in which the amplitude of a carrier wave is varied in direct proportion to that of a modulating signal. ... The term servo can refer to: Servomechanism - usually just shortened to servo, is a device used to effect mechanical motion for a specified distance. ...

The Mark III worked perfectly, but its appearance was quite that of a prototype, and not a finished, saleable product. It was in a makeshift wooden case, with several parts of its chassis externally mounted in partially-filled racks. So, Ampex went on to integrate all of this into a sleek metal console and fully-populated rack-mount cases, and this became the Mark IV.

The Mark IV was the machine for the first public demonstration of the 2 inch Quad format, at the NARTB (now the NAB) convention in Chicago on April 14, 1956. The earlier Mark III was given some cosmetic improvements, and was also demonstrated at Ampex headquarters in Redwood City the same day. Both demonstrations were a success, and as a result, Ampex was swamped with orders for the new 2 inch Quad VTR. The National Association of Broadcasters (NAB) is the industry group representing the commercial radio stations and television stations of the United States. ... Nickname: The Windy City Motto: Urbs In Horto (Latin: City in a Garden), I Will Official website: http://egov. ... April 14 is the 104th day of the year in the Gregorian calendar (105th in leap years). ... 1956 (MCMLVI) was a leap year starting on Sunday of the Gregorian calendar. ...

The VR 1000-B model (1961)

Ampex later released the first manufactured models of Quad VTR based on the Mark IV which were also prototypes, the VRX-1000, of which 16 were made. Machines made afterward were the final production models, and were designated as the VR-1000. Image File history File linksMetadata Download high resolution version (2048x1536, 675 KB) Summary An early type of video recorder. ... Image File history File linksMetadata Download high resolution version (2048x1536, 675 KB) Summary An early type of video recorder. ...

Shortly after Ampex's introduction of the 2 inch quad format, RCA in 1957 introduced a Quad-compatible VTR, the TRT-1A. RCA referred to it as a "Television Tape Recorder", since the word "Videotape" was a trademark of Ampex at the time. For other uses, see RCA (disambiguation). ... 1957 (MCMLVII) was a common year starting on Tuesday of the Gregorian calendar. ...

Later on, Ampex would release later models of their Quad decks, such as the second-generation VR-2000 in 1967, and the AVR series of VTRs, AVR-1, AVR-2, and AVR-3 in the 1970s. The AVR-2 was the most compact of Quad VTRs, and could run off on regular 120 volt single-phase household-type AC power (Quad VTRs before then required 208 or 220-volt 3-phase AC power). 1967 (MCMLXVII) was a common year starting on Sunday of the Gregorian calendar (the link is to a full 1967 calendar). ... The generation of AC electric power is commonly three phase, in which the waveforms of three supply conductors are offset from one another by 120°. These three conductors are commonly housed in a single conduit (e. ... 3-phase power, commonly used in industrial and theatrical installations, features three live legs of power and one neutral conductor. ...

RCA would also release later models of Quad VTRs as well, such as the TR-22 and TR-600.

CBS was the first television network to use 2 inch Quad videotape, using it for a West Coast delay of Douglas Edwards and the News on November 30, 1956. CBS would also delay for the west coast the first entertainment tv program on videotape, The Edsel Show, on October 13, 1957. For other uses, see CBS (disambiguation). ... The CBS Evening News is the flagship nightly television news program of the American television network CBS. It has broadcast since 1948. ... November 30 is the 334th day (335th on leap years) of the year in the Gregorian Calendar, with 31 days remaining, as the final day of November. ... 1956 (MCMLVI) was a leap year starting on Sunday of the Gregorian calendar. ... The title image from The Edsel Show The Edsel Show was an hour-long television special broadcast live on CBS in the United States on October 13, 1957, intended to promote Ford Motor Companys new Edsel cars. ... October 13 is the 286th day of the year (287th in leap years). ... 1957 (MCMLVII) was a common year starting on Tuesday of the Gregorian calendar. ...

The developing engineers at Ampex that worked on 2 inch Quadruplex videotape from the Mark I to the VR-1000 were Charles Ginsburg, Alex Maxey, Fred Pfost, Shelby Henderson, Charlie Anderson, and Ray Dolby (who later went on to found Dolby Laboratories). Charles Ginsburg (1920-1992) was the leader of a research team at Ampex Corporation which developed one of the first practical videotape recorders. ... Charlie Anderson (born December 8, 1981 in Jackson, Mississippi) is an American football player who currently plays linebacker for the Houston Texans. ... ` Dolby (left) is inducted into the NIHF Ray Dolby (born January 18, 1933) is the American inventor of the noise reduction system known as Dolby NR. He is the founder and chairman of Dolby Laboratories, and a billionaire. ... The Dolby logo Dolby Laboratories, Incorporated (Dolby Labs) (NYSE: DLB) is a company specializing in audio compression and reproduction. ...

2 inch Quad today

Nowadays, 2 inch Quad is no longer used as a mainstream format in TV broadcasting and video production, having been supplanted by more modern, easier-to-use, more practical and less high-maintenance formats like 1" Type C, U-matic, Betacam, DVCAM, DVCPro, and HDCAM. 1 Type C (designated Type C by SMPTE) is a professional open-reel videotape format co-developed and introduced by Ampex and Sony in 1976. ... Sony U-matic VTR BVU-800 A U-matic tape U-matic is the name of a videocassette format developed by Sony in 1969. ... Sony Betacam-SP VTR BVW-65 Betacam and VHS size comparison Betacam SP L (top), Betacam SP S (left), VHS (right) The early form of Betacam tapes are interchangeable with Betamax, though the recordings are not. ... DVCAM is Sonys professional implementation of the DV standard, using 15 micrometre tracks instead of DVs 10 micrometre tracks. ... DVCPRO, DVCPRO 50, and DVCPRO HD refer to digital videotape formats using the DV codec, and devised by Panasonic. ... Betacam and VHS size comparison Betacam SP L, Betacam SP S, VHS Betacam is a family of half-inch professional videotape formats developed by Sony from 1982 onwards. ...

When it was in use, 2 inch Quad VTRs needed ongoing maintenance, usually 3-phase power to operate (as mentioned earlier), plus an air compressor to provide air pressure for the air bearing that the spinning transverse headwheel rode on due to its high rotational speed (some Quad VTRs, such as the portable Ampex VR-3000, used ball bearings instead due to the lack of availability of compressed air, but these wore out quickly). They also required constant calibration of the discrete electronics used by the older Quad VTRs in order to maintain a high-quality picture suitable for broadcast. The operator was a much more skilled technician than today's "pop-in-a-cassette" operators. These machines required quite a bit of set up in order to make a quality recording and a broadcast quality image for playback. 3-phase power, commonly used in industrial and theatrical installations, features three live legs of power and one neutral conductor. ... Compressor has several meanings: A gas compressor is a mechanical device that takes in a gas and increases its pressure by squeezing a volume of it into a smaller volume. ... An air bearing is a bearing that literally consists of a layer of atmospheric air used as the working fluid for a fluid bearing. ...

2 inch Quad VTRs today are not used for broadcast or production service. Rather, they are now used by video archives and transfer services, for the transfer and/or restoration of 2 inch quad videotape material to a newer format.

See also

• Videotape

Bottom view of VHS videotape cassette with magnetic tape exposed Videotape is a means of recording television pictures and accompanying sound onto magnetic tape as opposed to movie film. ...

External links

• A page on video systems theory, with expanded information on the history of 2 inch Quad
• Quadruplex Park, an online museum of 2 inch Quad VTRs
• A page on "The Edsel Show", the first tv entertainment program delayed for the West Coast on videotape
• The History of Recording Technology, with a section with pictures on 2 inch Quad and Ampex's development and introduction of it