Tape cassette: description, photo, dimensions, purpose and principle of operation

2024 Author: Priscilla Miln | [email protected]. Last modified: 2024-01-01 17:06

With the advent of digital audio recording, the tape recorder, like its relatives (floppy disks with vinyl records), soon turned into stylish pictures, having lost its original meaning. Let's not write it off and find out what it was made of and how it works. And also consider what can be done from old cassettes that have become obsolete.

What is a tape cassette and "what does it eat with"

In Soviet stores, this miracle of technology was called MK. Many domestic consumers were ironic about the primitiveness of the name. After all, it was deciphered as "tape cassette". In fact, the MK was honestly torn off from the original English Music Cassette.

By the way, the phrase "tape cassette" familiar to us is not entirely correct. This storage medium (used to record sound) was widely used not only in tape recorders, but also in voice recorders,answering machines, and computers. Therefore, the official name of the device is "compact cassette" (Compact Cassette). The term "audio cassette" is less commonly used.

At one time, this medium was a breakthrough in the field of audio recording. After all, MKs were small and easy to handle, while records and reels took up a lot of space and easily failed.

In the period from the 70s to the 90s of the twentieth century. It was cassettes that were the most popular medium for recording and listening to music all over the world. Thanks to them, the size of the players has significantly decreased, and they have become portable. It is also to them that we should be grateful for the appearance of personal music players.

Description of tape cassette

At the peak of MK's popularity, more than a hundred companies were involved in its production. Despite this, they all adhered to the same standard. This guaranteed the versatility of the use of the compact cassette. Buying it in Japan, you could be sure that it would work on German, Soviet, and American tape recorders or players.

Let's look at what a typical MC was made of.

All of its parts were enclosed in a protective plastic case. Its dimensions are just the typical size of a tape cassette. It is equal to: 100.4 x 63.8 x 12 mm.

In cheap MK, this part was solid. This did not allow it to be repaired and disassembled. For more expensive ones, it consisted of halves twisted with tiny screws (4 or 5 pcs.).

As for the color of the case, it was originally colored. Later, MK began to be made from less durable transparent plastic. This was due not only to its cheaper cost, but also to the fact that it allowed you to see what was happening inside the cassette.

Inside the Music Cassette there are 2 miniature bobbins with a diameter of 2-2.2 cm each. The ends of the magnetic tape are fixed on them. Each middle of such a core has a hole with 6 teeth. They are what allow the player's drive shafts to drive the cassette.

If the tape is fully wound on one of the spools, the diameter of the circle is 5.2 cm.

In both lower corners, the MK is located along a tiny guide roller. When the tape moves, it is they who set its position strictly along the axis of the body.

At the bottom center there is a magnetic screen and a pressure spring with a pad of felt. It is needed so that the tape is pressed against the magnetic head as tightly as possible, but at the same time it is not injured. It also cleans the film of possible dust.

On the case of the MK there are several technical holes, which include elements of the tape drive mechanism of the reproducing device. For example, these are 2 symmetrical round holes at the bottom, not far from the clamping spring. Or the two rectangular slots surrounding it for the erase head (in case of overwriting a cassette).

In addition, later MK models had special slots on top that "helped" the tape recorder "detect" the type of tape being used automatically.

Features of the film inMK

The heart of any cassette and at the same time its memory is a magnetic tape. All information is recorded or rewritten on it. For this, 2 tracks (mono) or 4 (stereo) are used.

Standard film speed is 4.76cm/s. In later two-cassette tape recorders, it became possible to transfer from one MK to another in an accelerated mode: 9.53 cm / s.

As with reels, the cassette tape is based on a polymer film coated with a layer of powder of magnetic metals or their oxides.

In the first cassettes they were covered with Fe₂O₃. However, the quality of recording and playback of this type of MK was significantly inferior to the film based on CrO_{2. Subsequently, SONY developed a technology for the production of a two-layer tape with oxides of both chromium and iron. It conveyed better what was recorded, but it was more capricious film coated with metal powder.}

Each of the above types of coating had its own color and scope.

• Brown is Type I based on Fe₂O_3.
• Black - the so-called Metal Type IV.
• Dark Blue based on CrO_{2 - Type II.}
• Type III - mixed film. Brown on one side and dark blue on the other.
• There is also a white tape in cassettes. This is a leader. That is, a film that does not contain a ferromagnetic coating, and hence records. In addition to white, the leader can be transparent or with red hitchhiking marks.

Despite the difference in coating, the MK tape has the same width - 3, 81mm.

The film thickness standard is 18 µm and 27 µm. In the first case, the tape is designed for 90 minutes of operation. In the second - for an hour. These varieties were the most used. Although at different times MK appeared both at 10 minutes and at 240. However, films over 90 minutes were too thin and unreliable.

Compact cassette for voice recorder

As mentioned above, the classic MK has parameters of 100, 4 x 63, 8 x 12 mm. Especially for voice recorders and answering machines, the so-called microcassette (MMK) was developed. Its dimensions are twice as modest as those of a traditional MK: 50 x 33 x 7 mm.

Although the principle of operation of a tape cassette and MMK is similar, the internal structure differs not only in size.

• The voice recorder has a double set of springs and felt pads.
• The length of the tape is not 90 minutes, but half an hour or an hour.
• Film speed: 2.38 cm/s.
• To save space, MMK may not have a leader.
• Unlike conventional cassettes, these do not have a through channel, and the placement of the pressure roller and heads is somewhat non-standard.

Despite the lesser popularity and narrow application specifics, microcassettes were more expensive than conventional ones.

MS operation principle

Having de alt with the MK device, it is worth finding out how it functions. At the heart of everything is the principle of magnetic recording.

The film in the cassette is coated with a ferromagnetic compound (based on Fe₂O₃ or CrO_{2). When it is pulled in front of an electromagnet (which is powered by reinforcedcurrents generated by the microphone) changes in magnetization occur in the metal particles (corresponding to the current fluctuations that were caused by the sound). Thus, data is entered on the tape, that is, recording occurs. Theoretically, this can be not only sound, but also video and other information.}

Its playback occurs by pulling the tape through a similar magnet in a tape recorder or player. Only this time he "reads" the "pattern" formed by the particles and transforms it into sound. And through the amplifier and loudspeaker it feeds to the speakers.

As you can see, everything ingenious is simple. However, the cassette had to go through a lot of transformations to get there.

A Brief History of MK

The "mother" of tape cassettes (photo below) can be considered reels of magnetic tape, and the "grandmother" - records. The purpose of the invention of all these devices was the desire of mankind to preserve music or other sounds in eternity. However, gramophone records (appeared as early as the 19th century) could not make a long recording. The bobbins were bulky and required constant rearrangement.

In the early 30s. 20th century the idea arose to combine the feed and receive reels of a tape recorder in one case. The first experiments of this kind were carried out in pre-war Germany. Already in 1935-1936. The first compact cassette was designed. True, she worked on the wire. The outbreak of World War II put a stop to the development of this technology.

After the war, in the early 50s, Loewe Optaphon produced the world's first tape recorder using the cassette format in which the film was looped. This invention gave impetus to the development of this technology. Several variations of the compact cassette were released throughout the decade.

A new milestone in the history of MK is the cassette of the American company RCA. She was most similar to the carrier known today. The main difference was the dimensions: 197 × 127 × 13 mm. Despite this, it allowed only an hour of audio recording and playback (30 minutes per side) at 9.53 cm/s.

In the next few years, based on this development, a four-track format arose, and later eight. Such MKs were widely used only in the USA before the advent of the compact cassette.

1963 became a landmark year. It was then that the Dutch company Philips created the world's first full-fledged tape cassette. Due to its modest size, it was called the Compact Cassette, which was assigned to this product.

Fearing that the company's competitors will slightly improve their invention and force it out of the market, Philips management did not patent the technology and allowed everyone to use it. Soon cassettes a la "Philips" began to be produced by other companies around the world. They quickly supplanted all other developments in this area.

By the way, the production technology of a tape cassette in the USSR was also "borrowed" from the Dutch. True, with a lot of shortcomings. According to eyewitnesses, in an effort to ensureneeds of all the inhabitants of the country, MK were made of worse quality than their foreign counterparts. It got to the point that in production they did not even have time to tighten all the bolts on the cassette. In addition, the materials from which the film was made were of the lowest quality, which is why tape recorders often chewed it up. And after a few rewrites, it completely failed. Therefore, despite the fact that tape cassettes (photo in the article) from manufacturers such as Sony, Philips, TDK, Denon, Agfa, BASF cost 2 times more (compared to Soviet ones), buyers tried to use them.

The next stage in the evolution of MK was the invention of a magnetic tape for them based on CrO_{2. As a result, the recording quality has improved. Now compact cassettes have been able to force reels out of the market (which continued to be used mainly for studio recording).}

The incredible availability and ease of handling of these media has led to the birth and development of piracy against musicians' copyrights. Buying blank MK and copying from others was much cheaper than buying ready-made tape cassettes with recordings of performers. In the USSR (where there was no copyright), this problem did not appear. But the appearance of these devices stimulated the development of rock music, which was not very welcomed by the official censorship.

Compact cassettes reached their peak of popularity in 1985-1990. It was during this period that the largest number of them were produced and sold.

In the first five years of the 90s, MK continued to hold positions. However, since 1996 theirbegan to actively push CDs. Unlike cassettes, they held more information and did not require rewinding.

In the period 1996-2000. these carriers coexisted. Although cassettes were inferior to discs in many respects, not everyone still had devices for reading the latter. And the cost of their production was higher than that of MK.

With the advent of the new millennium and the digital age, cassette tapes were almost completely driven out of the market.

CD today

Although this media is obsolete, it continues to be produced. In most cases - for fans of retro. Although more often a surge of interest in MK is associated with fashion trends.

For example, in 2014 a movie from "Marvel" - "Guardians of the Galaxy" was released. One of the main characters, nostalgic about the past, listened to music on a Sony Walkman player. The desire of viewers to imitate him led to the fact that 10 million cassettes were bought in the same year, and the demand for them in the United States has continued to grow for many years.

It is noteworthy that in 2017 the long-awaited continuation of the film "Guardians of the Galaxy 2" was released, in which the father of the protagonist broke his rare player. Let's hope this doesn't hurt CD sales too much.

Scope of MK

From the very beginning, audio cassettes have been inferior to gramophone records and reels. Almost from the very moment of their appearance, they were positioned as a commodity for mass consumption. The point is that the qualityrecord playback for records and reels has always been significantly higher than for MK (as well as for modern digital discs). Because of this, professionals rarely worked with them.

So, where were these media used. In addition to tape recorders and players, MK was often listened to in cars instead of the usual radio. By the way, when the cassette technology was still in the process of being finalized, radio tape recorders were already being made for them.

If dictaphones were not very common in the USSR (compared to tape recorders), then in other developed countries they were used more than widely. Until the advent of the voice recorder format, almost half of all MKs produced were used in speech recording devices. They were used by secretaries, journalists, businessmen, writers and, of course, spies (where without them).

Considering the scope of MK, it is worth paying attention to one more device, familiar to most citizens of the USSR only from films. This is an answering machine. The same compact cassettes were used to record the message on it.

MK instead of floppy disk

At the dawn of personal computers, manufacturers faced the question: what to use as a carrier? Floppy disk technology was still crude, and punched cards were outdated. Tape cassettes were the solution. They (as well as drives for reading them) were much cheaper than floppy disks and their attributes.

Already by the end of the 70s. home PCs recorded data on cassettes. Initially, niches for MK were built into them. Later the technology was simplified. Now to the computera tape recorder was connected, which produced the recording / reading of the necessary data.

For immigrants from the USSR, this method of using cassettes became available only in the 80s. During this period, the Soviet industry pleased its citizens with the Kompanion PC. Its design and device was honestly stolen from the British counterpart ZX Spectrum.

To be fair, most families with a Companion used it not so much for work as for fun. And to this day, many old games on tape cassettes gather dust in chests of drawers. And in the late 80s and even early 90s for schoolchildren, they were the ultimate dream. Like a VCR or player.

Crafts from MK

Unlike European countries and the USA, there is no such general nostalgia for this carrier in the expanses of the former USSR. Vice versa. Those who still have old tape cassettes in their bins do not know what to do with this "happiness". Therefore, they come up with the most unimaginable ways to use them.

Wallets, handbags, lamps, furniture, paintings and even players are made from cases. Oddly enough, but one of the most popular crafts from old tape cassettes is caskets. Moreover, they are made not only from the cases of several MKs, but also knitted from the magnetic tape itself.

Such cassettes from old tape cassettes and crafts of a different kind are very popular. They are made not only for themselves, but also for sale. In almost any country in the world, on specialized sites, you can purchase both products from MK, and almost any tape cassette. Crafta.ua (Ukraine), "Fair of Masters" (RF), Amazon (USA), etc. - this is just a modest list of resources where such creations are sold.

So if you are the proud owner of several of these media in good condition, you can sell them or make something beautiful.

There is no single way to use tape cassettes to make sense of them, or at least recapture the money once spent on them. In any case, you should trust your own imagination. And she rarely fails. And if nothing comes to mind, you can put them back in the chest of drawers and wait for the popularity to come to this device and to us.