Cassette deck
A cassette deck is a type of tape machine for playing and recording audio cassettes that does not have a built-in power amplifier or speakers, and serves primarily as a transport. In the 1980s and early 1990s, tape decks were commonly used in vehicle stereo systems, portable cassette players, and home component systems. In the latter case, it is also called a component cassette deck or just a component deck.
History
Roots
The first consumer tape recorder to employ a tape reel permanently housed in a small removable cartridge was the RCA tape cartridge, which appeared in 1958 as a predecessor to the cassette format. At that time, reel-to-reel recorders and players were commonly used by enthusiasts but required large individual reels and tapes which had to be threaded by hand, making them less accessible to the casual consumer. Both RCA and Bell Sound attempted to commercialize the cartridge format, but a few factors stalled adoption, including lower-than-advertised availability of selections in the prerecorded media catalog, delays in production setup, and a stand-alone design that was not considered by audiophiles to be truly hi-fi.The compact cassette was introduced by the Philips Corporation at the Internationale Funkausstellung Berlin in 1963 and marketed as a device purely intended for portable speech-only dictation machines. The tape width was inch and tape speed was per second, giving a decidedly non-Hi-Fi frequency response and quite high noise levels.
Early cassette decks
Early recorders were intended for dictation and journalists and were typically hand-held battery-powered devices with built-in microphones and automatic gain control on recording. Tape recorder audio-quality had improved by the mid-1970s, and a cassette deck with manual level controls and VU meters became a standard component of home high-fidelity systems. Eventually the reel-to-reel recorder was completely displaced. There were usage constraints due to their large size, along with expense, and the inconvenience of threading and rewinding the tape reels. Cassettes are more portable and can be stopped and immediately removed in the middle of playback without rewinding. Cassettes became extremely popular for automotive and other portable music applications. Although pre-recorded cassettes were widely available, many users would combine songs from their vinyl records or other cassettes to make a new custom mixtape cassette.In 1970, the Advent Corporation combined Dolby B noise reduction system with chromium dioxide tape to create the Advent Model 200, the first high-fidelity cassette deck. Dolby B uses volume companding of high frequencies to boost low-level treble information by up to 9 dB, reducing them on playback. CrO2 used different bias and equalization settings to reduce the overall noise level and extend the high-frequency response. Together, these allowed a usefully flat frequency response beyond 15 kHz for the first time. This deck was based on a top-loading mechanism by Nakamichi. The follow-on Model 201 was based on a more reliable transport made by Wollensak. Both models featured an unusual single VU meter that could be switched between the two or for both channels together. The Model 200 featured piano key style transport controls, with the Model 201 using the distinctive combination of a separate lever for rewind and fast forward, and the large play and stop button as found on Wollensak commercial reel-to-reel machines of the era.
Most manufacturers adopted a standard top-loading format with piano key controls, dual VU meters, and slider level controls. There were then a variety of configurations leading to the next standard format in the late 1970s, which settled on front-loading with cassette well on one side, dual VU meters on the other, and later dual-cassette decks with meters in the middle. Mechanical controls were replaced with electronic push buttons controlling solenoid mechanical actuators, though low-cost models would retain mechanical controls. Some models could search for and count gaps between songs.
Widespread use
Cassette decks soon came into widespread use in applications such as home audio systems, mobile use in cars, as well as portable recorders. From the mid-1970s to the late 1990s, the cassette deck was the preferred music source for the automobile. Like an 8-track cartridge, it is relatively insensitive to vehicle motion, but has a smaller physical size and fast forward and rewind capability.A major boost to the cassette's popularity came with the release of the Sony Walkman personal cassette player in 1979, designed specifically as a headphone-only ultra-compact wearable music source. Although the vast majority of such players eventually sold were not Sony products, the name Walkman has become synonymous with this type of device.
Cassette decks were eventually manufactured by most of the well-known brands in home audio, and many in professional audio.
Performance improvements and additional features
Cassette decks reached their pinnacle of performance and complexity by the mid-1980s. Cassette decks from companies such as Nakamichi, Revox, and Tandberg incorporated advanced features such as multiple tape heads and dual-capstan drive with separate reel motors. Auto-reversing decks became popular and were standard on most factory-installed automobile players.Integrated noise reduction systems - Dolby B, C, and S
The Dolby B noise reduction system was key to realizing low noise performance on the, compared to reel-to-reel technology, relatively slow and narrow cassette tapes. It works by boosting the high frequencies on recording, especially low-level high-frequency sounds, with corresponding high-frequency reduction on playback. This lowers the high-frequency noise by approximately 9 dB. Enhanced versions included Dolby C and Dolby S types. Of the three, however, only Dolby B became common on automobile decks.Three heads for realtime monitoring of recordings and improved sound quality
Three-head technology uses separate heads for recording and playback, with the third of the three heads being the erase head. This allows different record and playback head gaps to be used. A narrower head gap is more optimal for playback than for recording, so the head gap width of any combined record/playback head must necessarily be a compromise. Separate record and playback heads also allow off-the-tape monitoring during recording, permitting immediate verification of the recording quality. Three-head systems were common on reel-to-reel decks, but were more difficult to implement for cassettes, which do not provide separate openings for record and play heads. Some models squeezed a monitor head into the capstan area, and others combined separate record and playback gaps into a single headshell.Auto reverse for automated sequential playback of both cassette sides
In later years, an auto-reverse feature appeared that allowed the deck to play on both sides of the cassette without the operator having to manually remove, flip, and re-insert the cassette. Most auto-reverse machines use a four-channel head, one pair for each direction, with only two channels connected to the electronics at a time. Auto-reverse decks employ a roller for each side. Since the second capstan and pinch roller use the same opening in the cassette shell normally used for the erase head, such decks must fit the erase head into the center opening in the shell along with the record and play head.Beginning in 1978, the auto reverse function may involve a standard two-track, quarter-width head assembly mounted on a small turntable which ducks down out of the tape path, mechanically rotates the head assembly 180 degrees, and quickly returns to the tape path so that the two head gaps access the other tracks of the tape as the reel and capstan motors reverse the tape direction. Sony introduced this solution in 1978, and JVC produced similar models in 1983. There is usually an azimuth adjustment screw for each head position. Nevertheless, due to the repeated movement, the alignment deviates with usage. Even in a machine with a four-channel head, slight asymmetries in the cassette shell make it difficult to align the head perfectly for both directions.
In one machine, the Dragon, Nakamichi addressed the issue with a motor-driven automatic head alignment mechanism. This proved effective but very expensive. Later Nakamichi auto-reverse models, the RX series, were essentially single-directional decks, but with an added mechanism that physically removed the cassette from the transport, flipped it over, and re-inserted it. Akai made a similar machine but with the mechanism and cassette laid out horizontally instead of upright. This permitted the convenience of auto-reverse with little compromise in record or playback quality.