Talk:Quadruplex videotape

Selected anniversaries/April 14
2 inch Quadruplex videotape is on the "On this day" section of the Main Page on April 14. General Eisenhower 23:59, 14 April 2006 (UTC)

Three Phase Supply
I worked with the VR1000, 1200, 2000 and 2000B and none of these used three phase supply as the article claims. This was with 240v UK mains supply, so perhaps it was different for the US 120v models.

You are correct, UK units were not three phase, as they used half the amps.Telecine Guy 04:47, 7 June 2007 (UTC)

Yes, I had a VR1000 at home in the UK in late seventies (long story). To get it working I had to buy two 1kW 240V -> 110V autotransformers but it then worked from normal domestic single-phase power. My VR1000 only had two racks of valve (tube) amplifiers, servos (KT88), PSUs etc., rather than the three mentioned in the article, and the vacuum pump and compressor were built into the console for 'mobile' use (i.e. in a van (truck)!). I got it working in 405-line then converted it to 625, but unfortunately there was a defective head tip, so every 4th band in the picture was just noise. Fom memory, the whole thing took nearly 3kW as there were a fair number of valves (tubes) in the console as well as the racks. One more memory - the 1950's instruction manual had an amusing cartoon character on the flyleaf called Mr. V.D.O. Recorder! —Preceding unsigned comment added by John Logie (talk • contribs) 10:58, 2 April 2009 (UTC)

Article External Links

 * The first two contain no content.

12.208.201.235 20:22, 23 August 2007 (UTC)Bill_S


 * Fixed, thank you Telecine Guy 07:09, 25 October 2008 (UTC)

This article or section has multiple issues tag, lets talk

 * It does not cite any references or sources. Please help improve it by citing reliable sources. Tagged since April 2008.


 * Most of the references is in the External Links, these have not been make in a long time, so it cannot be referenced as nice as newer tech gear.


 * Its tone or style may not be appropriate for Wikipedia. Tagged since April 2008.


 * It would be nice if you gave a sample, this is old tech gear that engineers made and worked on.

Thank you Telecine Guy 07:09, 25 October 2008 (UTC)

IMPROPER SOURCING: Dates are completely wrong for the ACR-25, AVR 1, 2 AND 3.
Ok, multiple issues with the dates of many of the late 1960s and 1970s Quad decks. I'm a former Canadian Broadcasting Corporation (CBC) Broadcast engineer, and I know we bought our AVR-2s and ACR-25 machines in 1972, when the Jarvis/Mutual Street Master Control was rebuilt and computerized. The ACR-25 debuted in 1969. Not exactly sure when the AVR-2 came online, but CBC bought them in 1972. We bought lots of the crappy AVR-3s for the 1976 Montreal Olympics, as the CBC was the host broadcaster. I know we bought them in early spring 1976, so they could have been around in 1975. They were cursed, and were not in existence by the time I started working at the CBC. They were the first Quad machines to be sold off or deactivated, and were replaced by Sony BVR-2000 one-inch type C machines in the early 1980s. When I have some solid sources, I will be changing the dates (although I know what year the CBC bought their AVR-2s and ACR-25s, I'm not an official source ;-) ).--99.233.113.229 (talk) 20:59, 3 July 2016 (UTC)

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Types of Color
Check out the following details, which are important for the history of VTR color capabilities. Because of the nature of direct composite FM recording, the first, or nearly the first Ampex monochrome VTRs could actually record color, but poorly. Of course this poor quality capability was not advertised. Those same machines could not play back in color at all.

Around 1957, RCA designed color conversions for the Ampex machines, as already mentioned in the article. Color was recorded properly with high quality, but fine detail was compromised somewhat on playback because the early color machines used the heterodyne method to stabilize the color signal. The result was very good color on the new narrow band color receivers at home, but the fine luminance detail at home was compromised. With the heterodyne method, the 1.5 MHz bandwidth of Orange (skin tone) and cyan, was effectively reduced to 0.5 MHz, which had no noticible effect on the newer TV receivers with narrow band color processing. There was an effect on the 1954 and 1955 RCA Victor color receiver models, which had wide-band color processing.

Starting in 1962, the solid state RCA machines had an analog delay line TBC for direct color recovery, not using the heterodyne method. This direct color method restored 100 percent of the luminance detail that can be transmitted over the air. Picture detail at home was visibly improved.

Also, the RCA color track TV receivers of 1985 had wide-band I/Q color processing, which benefitted in color detail from stations playing video tapes on the newer post 1961 VTRs with direct color recovery.

Ampex as well had a similar improvement, and their own direct color equipment sometime around 1962. I think it was called colortek.

Ohgddfp (talk) 16:33, 27 February 2019 (UTC)

we were set a bit of homework when I was at college by a wag of a lecturer who wanted us to think: "describe the operation of the colortec module during playback of a 625 line SECAM tape" :-) duncanrmi (talk) 01:54, 15 March 2021 (UTC)

Steve Allen of Allen Electronics
This seems to be an error. Need some kind of reference because Mr. Allen's first name of the famous Allen Electronics was not Steve. Steve Allen was a famous entertainer and author. Ohgddfp (talk) 16:43, 27 February 2019 (UTC)

Uncited material in need of citations
I am moving the following uncited material here until it can be properly supported with inline citations of reliable, secondary sources, per WP:V, WP:NOR, WP:CS, WP:NOR, WP:IRS, WP:PSTS, et al. This diff shows where it was in the article. Nightscream (talk) 18:58, 29 August 2022 (UTC)

LEDE SECTION
...which was much more costly to utilize, could only be used once, was time-consuming to develop in a film laboratory, and could be ruined by light leaks. In addition, kinescope images were usually of obviously inferior quality to the live television broadcast images they recorded, whereas quadruplex videotape preserved almost all the image detail of a live broadcast.

A typical 4800 ft reel of 2 in quad tape holds approximately one hour of recorded material at 15 inches per second.

History
They were desperate to obtain a quicker, less expensive, and more practical solution.

In the early 1950s, Ampex and several other companies such as Bing Crosby Enterprises (BCE) and RCA were 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 an extremely high speed (around 120 in/s) in order to accommodate sufficient 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. At the same time, the BBC developed a similar stationary-head video tape recorder (VTR) system that saw some on-air use, called VERA (Vision Electronic Recording Apparatus).

...which now used transverse scanning. The Mark II used frequency modulation for recording video to tape, resulting in a much-improved, but still noisy, video image (the Mark I had used amplitude modulation, which resulted in a very poor-quality video signal reproduced from the tape, compounded as well by the shortcomings of the machine's arcuate scanning). The Mark III had improved signal-processing and servo electronics, resulting in much better video reproduction.

The Mark III worked well, 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. Ampex then built the Mark IV by putting Mark III components into a sleek metal console and fully populated rack-mount cases.

RCA was able to make the TRT-1A and its later machines compatible with 2-inch quad because Ampex assisted RCA in doing so, as an expression of gratitude for RCA assisting Ampex with making their later quad machines after the VR-1000 color-capable. Initially, the VR-1000 was only natively capable of recording and playing back black and white video, but RCA had modified several VR-1000s to record color video for the NBC TV network (which RCA owned at the time) in the late 1950s, since NTSC color video programming was already underway at NBC.

The Edsel Show, on October 13, 1957, was the first CBS entertainment program to be broadcast live to the nation from Hollywood, then tape-delayed for rebroadcast in the Pacific time zone.

Edit control
At first, editing was accomplished by physically cutting and splicing the 2" magnetic tape. The tape was "developed" using a solution of fine iron powder suspended in a liquid solvent, marketed as "Edivue" Magnetic Developer. Using a special splicing block (such as the then-industry standard Smith Splicer) equipped with a microscope to view the developed tracks, the editor could then see their patterns and then cut between them. Some 2" splicing blocks instead used a read-only tape head connected to an oscilloscope that enabled the editor to electronically view cue tones or the control track pulses on the tape to determine where the tape should be cut. See linear video editing for details.

Ampex developed and introduced all-electronic videotape editing, making the physical splicing of videotape practically obsolete, with its breakthrough Editec system in 1963; by recording cue tones on the tape, the editor could make frame-accurate edits.

RCA had an "electronic splicer" in their TR-4/5 and TR-22 VTRs for frame-accurate edits.

In 1967 EECO created and introduced the EECO-900 edit controller, which used their proprietary On-Time time code (the later and more standard SMPTE time code had not yet been developed), which was used in conjunction with the quad machines of the time, and was the successor to Ampex's Editec. The EECO-900 and On-Time timecode were developed from EECO's previous work and products developed for NASA for logging and timecoding of their telemetry tapes during space missions.

In 1971, CMX, a collaborative between CBS and Memorex, introduced the first computer-based edit controller using SMPTE time code for editing. The CMX 200 could control both the source (A-roll) and record (B-roll) quad VTRs. CMX continued to make more powerful edit controllers capable of controlling more VTRs and peripheral devices, such as switchers, DVEs and character generators.

In 1976, Bosch introduced the Mach One list-management edit controller, a lower-cost (and less powerful) post-production alternative to CMX edit controllers. At the time, both CMX and Bosch edit controllers utilized similar DEC computers as their basic hardware. The Fernseh division of Bosch in Germany released the BCM-40 quadruplex VTR in the 1970s. It was only marketed in Europe, and was not sold in the U.S.

As 1" Type B and 1" Type C VTRs came on the market, list-management editing bays sometimes used a combination of both 1" and 2" VTRs; however, 2" VTRs soon began to disappear from both broadcast and post-production facilities, as the newer 1" machines were smaller, more dependable, used tape that was far less expensive to purchase, and were capable of recording stereo audio tracks.

Ampex
The list of modules are:
 * Amtec: Horizontal TBC. All that was needed for B&W playback.
 * Colortec: Color TBC in line after the Amtec for color playback.
 * Editec: (1963) Cue tone editor for frame accurate editing.
 * Velcomp: Color velocity TBC correction for better color playback. Optional on some models.
 * Procamp: Processing amplifier on the final output. New composite sync insertion, level adjustment. Note: all quad VTRs have a procamp so as to obtain a standardized output from a recording. Ampex procamps were occasionally used to clean-up, hence to standardize network feeds.
 * Dropout compensation (DOC): Replaced snowy video spots where the FM signal on the tape is missing momentarily, caused by a defect or dust particles on the tape. Optional on some models, both Ampex and 3M made different models of DOC modules for quad VTRs that can interface with such.
 * The components of the VTR were the servo system, video record (modulator) and playback de-modulator) and power supply.

Комета (Kometa), Soviet Union
(Note: The Russian word «кадр» (kadr) means "frame".)
 * Кадр-1 (Kadr-1), B&W unit, tubes, 1961
 * Кадр-1Ц (Kadr-1Ts), color unit, tubes
 * Кадр-3 (Kadr-3), color unit, solid-state, 1968
 * Кадр-3П (Kadr-3P), 2 racks version of Kadr-3 intended for production trucks.
 * Кадр-3ПМ (Kadr-3PM)
 * Кадр-5 (Kadr-5), a Soviet AVR1 look alike

ЛОМО (LOMO), Soviet Union

 * Электрон-2М (Electron-2M)

Military applications
Because the Ampex VR-3000 model was self-contained portable, the U.S. military used it in a wide variety of reconnaissance applications in various vehicles and aircraft. Its ability to accurately record a wide bandwidth of signals, especially high-frequency signals, was a definite advantage for signals intelligence applications.

2-inch quad today
When it was in use, 2-inch quad VTRs required ongoing maintenance, usually 3-phase power or one-phase 230 V to operate, 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.)

Clear numbers
Might this go somewhere to clear up the complicated NTSC/PAL paragraph?