RCA Snap-Load tape cartridge history

Summary

In Sept 2019 I acquired a late-1960's RCA cartridge player and restored it to opearation, as reported on the linked Web page. Why? Well, in July 2019 I obtained a SDS MAGPAK tape cartridge. SDS is Scientific Data Systems; the MAGPAK data cartridge was used on the SDS 900 series of minicomputers. Details of that tape cartridge are on another Web page. The cartridge form-factor, turned out to be based on the RCA "Sound Tape Cartridge" or "Snap-Load Cartridge" format. I purchased some RCA carts as well, and then the recorder, in order to play the SDS tapes and to try to recover the data. - Herb Johnson

RCA "Snap-Load" Sound Tape cartridge

Wikipedia's entry on the RCA cartridge includes the following. My remarks are added in []'s.

"The RCA [Sound Tape brand] tape cartridge is a magnetic tape audio format that was designed to offer stereo quarter-inch reel-to-reel tape recording quality in a convenient format for the consumer market. It was introduced in 1958, following four years of development. This timing coincided with the launch of the stereophonic phonograph record. It was introduced to the market by RCA in 1958."

Wikipedia says the 1/4-inch tape runs at 3.75 inches/second and has four discrete sound-tracks; two per side as with open-reel 1/4-inch stereo tapes. The recorders also support 1.875 IPS. The RCA cartridge measures 5 X 7-1/4 inches has a hub-braking mechanism, and a knock-out on the top edge of the cassette for write-protect. Plastic windows into the cartridge show the amount of tape on each spool. In many ways, these features match those on the later Phillips audio tape cassette.

RCA 1YB-11 Tape Cartridge player/recorder

In Sept 2019 I acquired a nonworking RCA cartridge player, a model 1YB-11 mono player, a serial number in the 2000's. It's a vacuum tube model. A view of the tape heads shows a stereo head with two black bars representing the two magnetic pickups. There's an A/B switch on the player's deck to select one of these for the one-channel "monophonic" amplifier and speaker. I completed repairs of the player in late Sept 2019, as described on the linked Web page.

Inside a RCA recorder

Here's a schematic published in 1961, from one of RCA's service books, of the RCA Victor model 1YB29 "Flightline" recorder/player. This is not for the model 1YB-11 I've repaired, but it's very similar. It's a vacuum-tube system, not transistor. Note there's only one amplifier "channel" (not two for stereo) and an "A/B" switch to choose which of the stereo channels to play or record. Stereo models also had an A/B switch and I believe a stereo/mono switch. The 1YB-29 has a "magic eye" 6FG6 tube to display volume; my 1YB-11 has a neon lamp.

The tape signals are analog, not digital; the same technology as used on 1/4-inch "open reel" tape recorders of the day by RCA and others. RCA improved audio quality of those tapes, for more fidelity at lower tape speeds. In play, the amplifier gets tape signals from the read/write head and drives the speaker. In record, the amplifier gets signals from the microphone or other sources, and drives the read/write head to put magnetic signals on the tape. Also in record, a stage of the amplifier becomes an oscillator (71 kilocycles) which puts an AC "bias" on the audio signal to the tape. An erase head, contacting the tape before the read/write head, demagnetizes the tape in record mode before it's recorded upon.

RCA Victor tape cartridges and recorder/players

I'm studying the history of RCA's tape cartridge. I'll add and refine information as acquired. My opinions on RCA's markets are of course casual observations on my part. - Herb

RCA product history

Sometime in 1956, RCA began to investigate and consider various designs and products of audio magnetic tape and vinyl records, with the goals of consumer convenience in use and to produce stereophonic audio products with two channels of sound. RCA determined a particular audio tape cartridge physical format with two channels of stereo sound or playable/recordable each channel. They announced a tape cartridge product in 1959 - the one described on this Web page - and a number of player/recorder models. Tapes were offered as unrecorded, or pre-recorded with various works of music. Production began in about 1959 into the mid-1960's, when the product line and tapes were taken out of promotion. (There's some evidence RCA produced blank tapes for some time.)

RCA and a few other companies produced pre-recorded cartridge tapes and blank tapes. The RCA "Living Stereo" label used for open-reel recordings was also used for the cartridge product. I've seen RCA branded carts with copyrights from 1958 to 1964. "Bel Canto" distributed under the "Mercury", "Dot" and "Liberty" labels.

So what happened to this product? In the same period, RCA introduced stereophonic vinyl records and consumer audio equipment, which were compatible with monophonic vinyl records in production; the stereo records became a common format. Also: the records were cheaper (possibly $3 in 1960) than the prerecorded cartridges ($8 in 1959). It's plausible the market preferred vinyl records playable on any "record player", to RCA's cartridges dedicated only to RCA's players.

RCA Engineer: magnetic cartridge

The Aug-Sept 1959 edition of RCA Engineer magazine has a series of articles on the new tape cartridge product. Technical discussion of frequency response, production of prerecorded tapes, and design of the stereo tape head. In the same issue (not included with my PDF) is technical discussion of RCA's stereophonic LP (vinyl record), also a new product of RCA.

For more information:

A half-hour video on the RCA tape cartridge by "RetroTech". Apparently by a popular techie who reviews old technology with video presentations. This one seems pretty comprehensive; and "anything explained with a British accent sounds authoratative in the USA". But the video is backed by period technical reportage. "Technology improves over time" is a common theme. The video even has corrections! ;) The video shows a tape produced with the "RCA" logo from 1968; pretty late!.

RCA and others prerecorded cartridges

RCA produced a limited number of prerecorded tapes. Here's one I attempted to acquire; at the last minute the seller failed to provide it, no explanation given. a 1958 performance of Van Cliburn, a prominant young pianist of the era. The front of the case shows the RCA "KCS-4028" product number and details of the Carnegie Hall performance. Another cart which I own, is titled "Love in the Afternoon" by The Three Suns, from RCA's Living Stereo productions.

On Oct 15th 2019, the post delivered my 1962 "Breakfast at Tiffany's" RCA cartridge. Recorded in 1960-61 in Hollywood, originally composed by and conducted for this recording by Henry Mancini. I detail my results from this cartridge, and a sample digital recording, on my RCA cartridge player repair Web page.

2019 prices for cartridge tapes As I monitored a certain auction Web site in October 2019 for pre-recorded RCA cartridges; I came to the conclusion that these tapes are uncommon but available as used, with patience, for a few tens of dollars each. Many such tapes are of musical or comedy artists popular in the 1960's. Tapes of a more-popular-today artist, say Elvis, will cost more and get bought quickly.

Scientific Data Systems and the RCA cartridge

My interest in the RCA tape cartridge began in July 2019, when i obtained a SDS MAGPAK tape cartridge. SDS is Scientific Data Systems; the MAGPAK data cartridge was used on the SDS 900 series of minicomputers. Details of that tape cartridge, and decoding its data, are on another Web page. I initially played the SDS tape on an open-reel 1/4-inch tape recorder; then I played the SDS tape on the RCA player I obtained and repaired.

Patents

Text molded into the SDS cart contains two patent numbers. Patent 2,711,901 is described as R. A. von Behren in June 28 1955 "Magnetic recording tape and method of making same". Filed May 21 1952. It describes the B-H hysteresis curve for magnetic media, a frequency response, and a mechanical method for passing recording tape over a read/write device. It was assigned to 3M Company of St. Paul MN.

Patent 2,654,681 is described as Laurence B Lueck, assignor to 3M, Application Jan 27 1950, patented Oct 6 1953, "Magnetic Recording Tape". It describes "magnetic recording sheet material, particularly in the form of narrow tape for the storage of signals as magnetic impulses". Various materials and substances are mentioned and various issues are cited.

Ritter Company, Audiac, Dr. Gardner and Dr. Licklider

The Ritter Company of Rochester, NY, produced the "Audiac" product, which apparently used the RCA tape cartridge format. Ritter was and is today, a manufacturer of dental equipment. The Audiac was part of a dentist's working cabinet which also contained a cartridge player. The tapes were played for the patient, for audio - music or white noise - to distract them from dental procedures. Ritter sold blank and prerecorded cartridge tapes under their Ritter Audiac lable. Ritter Dental Manufacturing was established in 1887 and merged with other companies in the mid-1960's and decades since. Apparently it re-emerged as "Ritter Dental USA" as a dental equipment manufacturer in Germany with a Texas facility.

There's an article in the Aug 1960 Popular Science magazine "Who's afraid of the Dentist?" (Albert Q Maisel) which explains "audio-analgesia" development in 1958 by MIT acoustics expert and psychologist Dr. Joseph Licklider and dentist Dr. Wallace Gardner. Gardner apparently was the primary developer of the Audiac product. Other publications in or about the era, document the history of fatalities due to early 20th-century medical anesthesia. So the introduction of a safe but effective alternative was a noteworthy and popular development. Dr Gardner appeared in LOOK magazine in May 24 1960 as "Denistry went Hi-Fi". Interest in the method declined after several years. The arc of the Audiac is described in a Nov 2 2017 article in Oxford American magazine, "Outskirts of the Southern Canon" by Will Stephenson (Gardner's grandson).

Dr. Licklider was involved with early Internet developments, starting with his 1960's paper "Man-Computer Symbiosis". He worked at or with MIT (research and a director) and BBN (as a vice-president). Both organizations were developers of the ARPAnet which preceeded "the Internet". Biographies and awards credit him as a major figure - "a Johnny Appleseed" - in the development of late-20th century interactive personal computing and widespread computing networking.

I have no information about an association between Audiac and RCA; however the cartridges appear to be physically the same as the RCA product. The trademark "Audiac" was registered by Audiac Inc. in Dec 21 1965 for quote "MAKING RECORDINGS OF WEDDING CEREMONIES, AND THE LIKE". The trademark expired as of 1987. Unrelated, is a 2010's era German music performing group also called Audiac.

Herb Johnson
New Jersey, USA
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