Ampex Explained

Ampex Data Systems Corporation
Type:Subsidiary
Founder:Alexander Poniatoff
Hq Location City:Hayward, California
Hq Location Country:United States
Industry:Data and instrumentation technology for acquisition, storage, and processing of visual information
Products:miniR 700 Mini-Recorder, TuffServ 540 & 640 smart NAS, TuffCORD smart NAS, AMux700 DAU, BLUE IQ deep-learning data management, BLUE Sentry on-board cyber security
Parent:Delta Information Systems

Ampex Data Systems Corporation is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor.[1] The name AMPEX is a portmanteau, created by its founder, which stands for Alexander M. Poniatoff Excellence.[2] Ampex operates as Ampex Data Systems Corporation, a subsidiary of Delta Information Systems, and consists of two business units. The Silicon Valley unit, known internally as Ampex Data Systems (ADS), manufactures digital data storage systems capable of functioning in harsh environments. The Colorado Springs, Colorado, unit, referred to as Ampex Intelligent Systems (AIS), serves as a laboratory and hub for the company's line of industrial control systems, cyber security products and services and its artificial intelligence/machine learning technology.

Ampex's first great success was a line of reel-to-reel tape recorders developed from the German wartime Magnetophon system at the behest of Bing Crosby. Ampex quickly became a leader in audio tape technology, developing many of the analog recording formats for both music and movies that remained in use into the 1990s. Starting in the 1950s, the company began developing video tape recorders, and later introduced the helical scan concept that made home video players possible. They also introduced multi-track recording, slow-motion and instant playback television, and a host of other advances. Ampex's tape business was rendered obsolete during the 1990s, and the company turned to digital storage products.

Ampex moved into digital storage for DoD Flight Test Instrumentation (FTI) with the introduction of the first, true all digital flight test recorder. Ampex supports numerous major DoD programs with the US Air Force, US Army, US Marines, US Navy and other government entities (NASA, DHS and national labs). Ampex also works with all major DoD primes and integrators including Boeing, General Atomics, Lockheed, Northrop, Raytheon and many others.

Currently, Ampex is attempting to do more with the data stored on its network attached storage (NAS) devices. This includes adding encryption for secure data storage; algorithms focused on control system cyber security for infrastructure and aerospace platforms; and artificial intelligence/machine learning for automated entity identification and data analytics.

Origin

Russian–American inventor Alexander Matthew Poniatoff established the company in San Carlos, California, in 1944 as the Ampex Electric and Manufacturing Company. The company name came from his initials plus "ex" to avoid using the name AMP already in use (by Aircraft and Marine Products). During World War II, Ampex was a subcontractor to Dalmo-Victor, manufacturing high quality electric motors and generators for radars that used alnico 5 magnets from General Electric.[3] [4] Ampex was initially set up in an abandoned loft-space above the Dalmo-Victor plant; eventually they would have offices at 1313 Laurel Street, San Carlos, California (at the intersection of Howard Avenue and Laurel Street).[5]

Near the end of the war, while serving in the U.S. Army Signal Corps, Major Jack Mullin was assigned to investigate German radio and electronics experiments. He discovered the Magnetophons with AC biasing on a trip to Radio Frankfurt. The device produced much better fidelity than shellac records. The technological processes in tape recording and equipment developed by German companies before and during the 1939–1945 war were subject to patents which were effectively voided after Germany's 1945 surrender and defeat. Mullin acquired two Magnetophon recorders and 50 reels of BASF Type L tape, and brought them to America, where he produced modified versions. He demonstrated them to the Institute of Radio Engineers in San Francisco on May 16, 1946.[3]

Bing Crosby, a big star on radio at the time, was receptive to the idea of pre-recording his radio programs. He disliked the regimentation of live broadcasts, and much preferred the relaxed atmosphere of the recording studio. He had already asked the NBC network to let him pre-record his 1944–45 series on transcription discs, but the network refused; so Crosby had withdrawn from live radio for a year and returned (this time to the recently created ABC) for the 1946–47 season, only reluctantly.

In June 1947, Mullin, who was pitching the technology to the major Hollywood movie studios, got the chance to demonstrate his modified tape recorders to Crosby. When Crosby heard a demonstration of Mullin's tape recorders, he immediately saw the potential of the new technology and commissioned Mullin to prepare a test recording of his radio show. Ampex was finishing its prototype of the Model 200 tape recorder, and Mullin used the first two models as soon as they were built. After a successful test broadcast, ABC agreed to allow Crosby to pre-record his shows on tape. Crosby immediately appointed Mullin as his chief engineer and placed an order for $50,000 worth of the new recorders so that Ampex (then a small six-man concern) could develop a commercial production model from the prototypes.[3] [6]

Crosby Enterprises was Ampex's West Coast representative until 1957.

Early tape recorders

The company's first tape recorder, the Ampex Model 200A, was first shipped in April 1948. The first two units, serial numbers 1 and 2, were used to record Bing Crosby's show.[7] The American Broadcasting Company used these recorders along with 3M Scotch 111 gamma ferric oxide coated acetate tape[8] for the first-ever U.S. delayed radio broadcast of Bing Crosby's Philco Radio Time. Ampex tape recorders revolutionized the radio and recording industries because of their superior audio quality and ease of operation over audio disk cutting lathes.

The firm's earliest production of multichannel machines wasn't aimed at music recording; it noted in 195354 that "Ampex began the commercial production of multitrack tape recorders about four years ago for those interested in telemetered information from guided missiles and the like. These equipments provided any number of simultaneous channels up to 14. It was a simple step, therefore, to make stereophonic tape recorders with two or more channels."[9]

During the early 1950s, Ampex began marketing one- and two-track machines using NaNinches tape. In May 1953 the firm announced production of two- and three-track machines on 1/4 inch tape.[10] The line soon expanded into three- and four-track models using NaNinches tape. In the early 1950s, Ampex moved to Redwood City, California. Ampex acquired Orradio Industries in 1959, which became the Ampex Magnetic Tape Division, headquartered in Opelika, Alabama. This made Ampex a manufacturer of both recorders and tape. By the end of that decade Ampex products were much in demand by top recording studios worldwide.

In 1952, movie producer Mike Todd asked Ampex to develop a high-fidelity movie sound system using sound magnetically recorded on the film itself, as contrasted with the technology of the time, which used magnetic tracks on a separate celluloid base film (later commonly known as mag stock). The result of this development was the CinemaScope/Todd-AO motion picture sound system,[11] which was first used in movies such as The Robe (1953) in 35mm and Oklahoma (1955) in 70mm (and also in 35mm). In 1960, the Academy of Motion Picture Arts and Sciences awarded Ampex an Oscar for technical achievement as a result of this development.

Les Paul, a friend of Crosby and a regular guest on his shows, had already been experimenting with overdubbed recordings on disc. He received an early portable Ampex Model 300 from Crosby. Using this machine, Les Paul invented "Sound on Sound" recording technology. He placed an additional playback head, located before the conventional erase/record/playback heads. This allowed Paul to play along with a previously recorded track, both of which were mixed together on to a new track. This was a destructive process because the original recording was recorded over.[12]

Professional 8-track recorders

See main article: History of multitrack recording. Ampex built a handful of multitrack machines during the late 1950s that could record as many as eight tracks on 1inches tape. The project was overseen by Ross Snyder, Ampex manager of special products. To make the multitrack recorder work, Snyder invented the Sel-Sync process, which used some tracks on the head for playback and other tracks on the head for recording. This made the newly recorded material be in sync with the existing recorded tracks.[13] The first of these machines cost $10,000 and was installed in Les Paul's home recording studio by David Sarser.[14] [15]

In 1967, Ampex responded to demand by stepping up production of their 8-track machines with the production model MM 1000. Like earlier 8-track machines of this era, it used 1-inch tape.

16 and 24-track recorders

In 1966, Ampex built their first 16-track recorder, the model AG-1000, at the request of Mirasound Studios in New York City. In 1967, Ampex introduced a 16-track version of the MM 1000 which was the world's first 16-track professional tape recorder put into mass-production. Both used a 2inches tape transport design adapted from the video recording division. The 16-track MM-1000 quickly became legendary for its tremendous flexibility, reliability and outstanding sound quality. This brought about the "golden age" of large format analog multitrack recorders which would last into the mid-1990s. MCI built the first 24-track recorder (using 2-inch tape) in 1968 which was installed at TTG Studios in Los Angeles. Later machines built by Ampex starting in 1969 would have as many as 24 tracks on 2 inch tape. In addition to this, the introduction of SMPTE time code allowed studios to run multiple machines in perfect synchronization, making the number of available tracks virtually unlimited.

By the 1970s, Ampex faced tough competition from the Swiss company Studer and Japanese manufacturers such as Otari and Sony (who also purchased the MCI brand in 1982). In 1979, Ampex introduced their most advanced 24-track recorder, the model ATR-124. The ATR-124 was ruggedly constructed and had audio specifications that nearly rivaled the first digital recording machines. However, sales of the ATR-124 were slow due to the machine's high price tag. Ampex sold only about 50 or 60 ATR-124 machines and withdrew from the professional audio tape recorder market entirely in 1983.

The 1990s

By the 1990s Ampex focused more on video recorders, instrumentation recorders, and data recorders. In 1991, Ampex sold their professional audio recorder line to Sprague Magnetics.[16] The Ampex Recording Media Corporation spun off in 1995 as Quantegy Inc.; that company has ceased producing recording tape.

Video technology

Video processing

See main article: Video Processing. While AMPEX are well recognized for their contribution to magnetic tape recording, they also had a huge impact on developments the whole video signal chain.They did rebadge some specialist low-volume OEM products to complete the package, but their in-house teams developed industry leading products in the following categories:

Digital optics

ADO Ampex Digital Optics provided comprehensive frame manipulation in 2 and 3 dimensions. Adjusting the aspect, size, and rotation of the image was performed continuously in real-time. An optional digital 'combiner' was available to perform the foreground layering and priority switching – to reduce the burden on the vision mixer with multi-channel effects.

Video switching and effects

AVC – The AVC range of vision mixers ranged from small, single buss devices up to the high-end Century Series, with multiple Mix/Effect busses, infinite re-entry and powerful keying and control software.

Editing controllers

The product line evolved quickly from manual editing on the actual VTRs themselves to incorporate SMPTE timecode providing advanced timeline control.The RA-4000 and EDM-1 were fully functional early products, but soon evolved to the extremely powerful ACE family to compete with CMX and other edit controller brands.

Quadruplex two-inch tape

See main article: Quadruplex videotape. Starting in the early 1950s, RCA, Bing Crosby and others tried to record analog video on very fast-moving magnetic tape. As early as 1952, Ampex developed prototype video tape recorders that used a spinning head and relatively slow-moving tape. In early 1956, a team produced the first videotape recorder.[17] A young, 19-year-old engineer Ray Dolby was also part of the team.[3] Ampex demonstrated the VR-1000, which was the first of Ampex's line of 2-inch Quadruplex videotape recorders on April 14, 1956, at the National Association of Radio and Television Broadcasters in Chicago. The first magnetically recorded time-delayed television network program using the new Ampex Quadruplex recording system was CBS's Douglas Edwards and the News on November 30, 1956.

The "Quad" head assembly rotates at 14,400 rpm (NTSC). The four head pieces (quad) are switched successively so that recorded stripes cross the video portion (most of the tape middle, audio is on one edge, control track is on the other) so that head to tape write speed is well in excess of the 15in/s physical motion. They wrote the video vertically across the width of a tape that was wide and ran at 15inches per second. This allowed hour-long television programs to be recorded on one reel of tape. In 1956, one reel of tape cost $300; and Ampex advertised the cost of the recorder as $45,000.[18] A 7.5in/s version was released later, and this required a new, narrower headwheel. This vertical writing facilitated mechanical editing, once the control track was developed to display the pulse that indicates where a frame ends and the next one begins. Later, Ampex developed electronic editing.

The National Academy of Television Arts and Sciences awarded Ampex its first Emmy in 1957 for this development. Ampex received a total of 12 Emmys for its technical video achievements.

In 1959, Richard Nixon, then Vice President, and Nikita Khrushchev held discussions at the Moscow Trade Fair, which became known as the "Kitchen Debate" because they were mostly held in the kitchen of a suburban model house. These discussions were recorded on an Ampex color videotape recorder,[19] and during the debate Nixon pointed this out as one of the many American technological advances.

In 1967, Ampex introduced the Ampex VR-3000 portable broadcast video recorder, which revolutionized the recording of broadcast quality television in the field without the need for long cables and large support vehicles. Broadcast quality images could now be shot anywhere, including from airplanes, helicopters and boats.

The Quadruplex format dominated the broadcast industry for a quarter of a century. The format was licensed to RCA for use in their "television tape recorders." Ampex's invention revolutionized the television production industry by eliminating the kinescope process of time-shifting television programs, which required the use of motion picture film. For archival purposes, the kinescope method continued to be used for some years; film was still preferred by archivists. The Ampex broadcast video tape recorder facilitated time-zone broadcast delay so that networks could air programming at the same hour in various time zones. Ampex had trademarked the name "video tape", so competitor RCA called the medium "TV tape" or "television tape". The terms eventually became genericized, and "videotape" is commonly used today.

While the quadruplex recording system per se is no longer in use, the principle evolved into the helical scanning technique used in virtually all video tape machines, such as those using the consumer formats of VHS, Sony Betamax and Video 2000. Sony Betacam was successful as a professional format but operated with a different recording system and faster tape speed than Betamax.

One of the key engineers in the development of the Quadruplex video recorder for Ampex was Ray Dolby, who worked under Charlie Ginsburg and went on to form Dolby Laboratories, a pioneer in audio noise reduction systems. Dolby's contribution to the videotape system was limited to the mathematics behind the reactance tube FM modulator, as videotape then used FM modulation for the video portion. Another contributor designed the FM modulator itself. Dolby left Ampex to seek a PhD in physics in England, which is where Dolby Labs was later founded, before moving back to San Francisco. Dolby's brother Dale was also an engineer at Ampex.

VR-5000 and VR-8000

In 1961, Ampex introduced the first 1-inch helical scan video recorders, the Ampex 2-inch helical VTRs, which recorded video using helical scan recording technology on tape.

Ampex 2-inch helical VTR

See main article: Ampex 2 inch helical VTR. Ampex 2 inch helical VTRs were manufactured from 1963 to 1970. Model VR-1500 for home. The VR-660 for Broadcast television systems, industrial companies, educational institutions, and a few for In-flight entertainment. The VR-1500 and VR-660 found service at educational institutions especially due to their relatively low cost vs. 2inches quadruplex VTRs. These machines were simple to operate, reliable, small in size—and produced, for their time, very good video without the complexity of the larger and much more complex 2" Quad machines.

HS-100 and HS-200 "slo-mo" disc recorder

In March 1967, Ampex introduced the HS-100 video disc recorder. The system was developed by Ampex at the request of the American Broadcasting Company (ABC) for a variety of sports broadcast uses. It was first demonstrated on the air on March 18, 1967, when ABC's Wide World of Sports televised the "World Series of Skiing" from Vail, Colorado.[20] The video was recorded on analog magnetic disc. The disc weighed and rotated at 60 rps, 3600 rpm (50 rps in PAL). One NTSC unit could record 30 seconds of video, PAL units 36 seconds. The video could then be played back in slow motion, stop action to freeze frame.[21]

A more deluxe version, the HS-200, was introduced in April 1968,[22] and provided a large control console with variable speed playback. This made it ideal for instant replay for sports events and precise timing control in post-production service. CBS-TV was the first to use the technique during live sportscasts, though it was quickly adopted by all American TV networks. The HS-200, which was an HS-100 connected to a control console, had greater precise frame and timing control capability, lending itself to post-production applications like special effects and titles. The HS-200 had a frame accurate timing computer that enabled frame-accurate cuts and dissolve transitions by way of a two-input video switcher. Slow-motion sequences could likewise be programmed and could be "triggered" to begin via an external control pulse such as might come from an external VTR editor like the Ampex VR-2000 VTR with Editec. The HS-200 was the first system capable of single-frame video animation recording, using magnetic discs as opposed to videotape. The HS-200 also provided a readout with specific frame numbers showing from the 900 frames available (NTSC version). Sequences could be triggered to start from any of these 900 frames with frame-accurate repeatability for creative fine tuning of sequence start and end points.

Type A

See main article: 1 inch type A videotape. 1 inch type A videotape (designated Type A by the Society of Motion Picture and Television Engineers, SMPTE) was an open-reel helical scan videotape format developed by Ampex in 1965, one of the first standardized open-reel videotape formats in the width; most others of that size at that time were proprietary.

Type C

See main article: 1 inch type C videotape. 1 inch type C videotape (designated Type C by SMPTE) was a professional open-reel videotape format co-developed and introduced by Ampex and Sony in 1976. It became the replacement in the professional video and television broadcast industries for the then-incumbent Quadruplex.

D2

See main article: D2 (video format). D2 is a digital video tape format created by Ampex and other manufacturers (through a standards group of SMPTE) and introduced at the 1988 NAB (National Association of Broadcasters) convention as a lower-cost alternative to the D-1 format. Like D-1, D-2 video is uncompressed; however, it saves bandwidth and other costs by sampling a fully encoded NTSC or PAL composite video signal, and storing it directly to magnetic tape, rather than sampling component video. This is known as digital composite.

DCT and DST

See main article: Digital Component Technology. Digital Component Technology (DCT) and Data Storage Technology (DST) are VTR and data storage devices respectively, created by Ampex in 1992. Both were similar to the D1 and D2 VTR formats, using a 19adj=onNaNadj=on width, with the DCT format using DCT (discrete cosine transform) video compression, also its namesake.

The DCT and DST formats yielded relatively high capacity and speed for data and video. Double-density DST data storage was introduced in 1996. The final generation of these products were quad density, introduced in 2000, resulting in a large cartridge holding 660GB of data.

Milestones

Sticky-shed syndrome

Some master tapes and other recordings predominantly from the 1970s and 1980s have degraded due to the so-called sticky-shed syndrome. When sticky-shed syndrome occurs, the binding agent deteriorates, resulting in the magnetic coating coming off the base and either sticking to the backing of the tape layer wound on top of it (resulting in dropout), or being scraped off and deposited on the tape heads while lifting the head off the tape, degrading the treble.

The problem has been reported on a number of makes of tape (usually back-coated tapes), including Ampex tapes.

Ampex filed [24] for a baking process ("A typical temperature used is 54°C and a typical time is 16 hours") to attempt to recover such tapes, allowing them to be played once more and the recordings transferred to new media. The problems have been reported on tapes of type 406/407, 456/457, 2020/373.

Branding

Record labels

Ampex Records was started in 1970. Its biggest hit was "We Gotta Get You A Woman" by Todd Rundgren (as "Runt"), reaching No. 20 on the Billboard Hot 100 chart in 1970. Ampex also originated three subsidiary labels: Bearsville, Big Tree, and Lizard. Ampex Records ceased operations around 1973; Bearsville and Big Tree switched distribution respectively to Warner Bros. Records and Bell Records, and Lizard became an independent entity. Later on, Big Tree was picked up by Atlantic Records.

Legal history

In 2005, iNEXTV, a wholly owned subsidiary of respondent Ampex Corporation, brought a defamation lawsuit against a poster on an Internet message board who posted messages critical of them (Ampex Corp. v. Cargle (2005), Cal.App.4th). The poster, a former employee, responded with an anti-SLAPP suit and eventually recovered his attorney fees. The case was unique in that it involved the legality of speech in an electronic public forum.[26]

Present Day -- Since 2014

After becoming part of Delta Information Systems in 2014, two former subsidiaries of Ampex Corporation continued business as part of the Ampex legacy. Ampex Data Systems Corporation (ADSC) headquartered in Silicon Valley, and its subsidiary, Ampex Japan Ltd. are the only two Ampex businesses that still trade as more than "in name only" entities.

Ampex Data Systems operates out of main three locations in the USA: the headquarters in Hayward, CA (about a dozen miles from the Redwood City location in Silicon Valley), a program office in Colorado Springs, CO and an engineering center in Las Cruces, NM, as well as from the main Delta HQ in Horsham, PA. Ampex continues to produce rugged data storage products used by government, military and commercial customers world-wide.

Since joining Delta, Ampex has grown in revenue and headcount, employing significantly more people in 2023 than were employed under the previous management structure.

Legacy and Archives

The Ampex video system is obsolete, but many thousands of quadruplex videotape recordings remain. Machines that survive are used to transfer archival recordings to modern digital video formats.

Ampex Corporation supported the Ampex Museum of Magnetic Recording, started by Peter Hammar in 1982.[27]

The contents of that museum were donated to Stanford in 2001.[28] [29] A project is underway to curate Ampex artifacts in physical and digital form. This project will find a permanent home in Redwood City for the Ampex Museum and digital artifacts will be curated at AmpexMuseum.org[30] This project is being funded by contributions from former Ampex employees.

See also

Further reading

External links

Notes and References

  1. Book: Nmungwun, Aaron Foisi . Video Recording Technology: Its Impact on Media and Home Entertainment . November 12, 2012 . Routledge . 9781136466045.
  2. Abramson,The History of television, 1942 to 2000 – McFarland, 2003 –, page 286, Chapter 2, footnote 34 "1944 he founded Ampex (the name was created from his initials, AMP, plus "ex" for excellence)"
  3. http://history.sandiego.edu/GEN/recording/magnetic4.html The History of Magnetic Recording by Steven Schoenherr, University of San Diego, November 5, 2002
  4. Book: Kenney, Martin . Understanding Silicon Valley: The Anatomy of an Entrepreneurial Region . 2000 . Stanford University Press . 9780804737340.
  5. Web site: Pictures. 22 November 2016.
  6. Careless, James. The Ever-Evolving Role of Airchecks. Radio World. May 22, 2019 . 43. 13. 18.
  7. Web site: History of The Early Days of Ampex Corporation As recalled by JOHN LESLIE and ROSS SNYDER, AES Historical Paper, Dec 17, 2010. April 5, 2023.
  8. http://history.sandiego.edu/GEN/recording/notes.html Recording Technology History: Tape Recording Comes to America
  9. Tinkham, Russell J. "Stereophonic Tape Recording Equipment." Journal of the SMPTE, January 1954, 71. (Based on Ampex's presentations to the SMPTE in 1953, as noted in this journal article.)
  10. Tinkham, Russell J. "Stereophonic Tape Recording Equipment." Journal of the SMPTE, January 1954, 71.
  11. The 1952 divestiture of Western Electric Company's motion picture sound unit from the Bell System prevented it from completing this project, which Ampex took over, considerably simplified it for manufacturability and lower cost, and for improved magnetic head lifetime, and brought it to market in high volume, in some cases with a market penetration exceeding 90 percent.
  12. Web site: Sel-sync and the "Octopus": How Came to be the First Recorder to Minimize Successive Copying in Overdubs . ARSC Journal . August 11, 2019.
  13. Web site: Ampex Sel-Sync, 1955. https://web.archive.org/web/20100131104600/http://mixonline.com/mag/audio_ampex_selsync/. dead. January 31, 2010.
  14. Web site: Studio 3; A Place Of Recording History. 22 November 2016.
  15. Web site: ARSC Journal, Sel-sync and the "Octopus": How Came to be the First Recorder to Minimize Successive Copying in Overdubs. August 13, 2009. May 19, 2011. https://web.archive.org/web/20110519105331/http://www.aes.org/aeshc/docs/sel-sync/snyder_sel-sync.pdf. dead.
  16. Web site: About Us. Spague Magnetics. https://web.archive.org/web/20110716122208/http://www.sprague-magnetics.com/about.htm. 16 July 2011. dead. 22 November 2016.
  17. Web site: Peninsula Electronics. https://web.archive.org/web/20100301090227/http://www.siliconvalleyhistorical.org/home/peninsula_electronics. dead. March 1, 2010.
  18. "How Much Should a Tape Recorder Cost? [Ampex ad]" Broadcasting-Telecasting, 15 October 1956, 220. http://americanradiohistory.com/Archive-BC/BC-1956/1956-10-15-Quarter-Century-BC.pdf
  19. http://www.aes.org/aeshc/docs/recording.technology.history/magnetic4.html Audio Engineering Society;  The History of Magnetic Recording by Steven Schoenherr, University of San Diego, Nov. 5, 2002
  20. http://www.digitrakcom.com/literature/HS-100%20Press.pdf HS100 Press
  21. http://www.vtoldboys.com/slomo_3.htm HS100
  22. Web site: Ampex Products Chronology.
  23. Wingo . Dennis R. . Cowing . Keith L. . March 23, 2009 . RECOVERING HIGH RESOLUTION LUNAR ORBITER IMAGES FROM ANALOG TAPE . 40th Lunar and Planetary Science Conference (2009) . Lunar and Planetary Institute . Houston, TX . February 12, 2022.
  24. http://www.richardhess.net/restoration_notes/USP5236790.pdf Archived copy
  25. Web site: Quantegy Finally Goes Tapeless. https://archive.today/20120915101112/http://www.radioworld.com/article/1412. dead. 15 September 2012. RWO. 22 November 2016.
  26. FindLaw Ampex Corp v. Cargle (2005)
  27. "The Ampex Museum of Magnetic Recording" by curator Peter Hammar. "Electronic Servicing & Technology" magazine 1982 June.
  28. http://www.aes.org/aeshc/museums/apx.stanford/ampex_museum_status_report_2003-10-01.html "Ampex Museum Status Report 2003"
  29. Web site: "Ampex Virtual Museum" . January 29, 2008 . February 9, 2008 . https://web.archive.org/web/20080209075307/http://recordist.com/ampex/ . dead .
  30. http://AmpexMuseum.org/ "AmpexMuseum.org"