Glossary

ALC: Automatic Level Control. This device adjusts the signal level that goes onto the tape during recording to prevent overloading it and causing distortion. As well as making the recorder easier to use, it saves the manufacturer having to fit a level indicator and control, both of which are bulky items. Miniature recorders such as the WM-R707 and simple low cost models, like the TC-12 use ALC, though it is not considered suitable for professional recorders, for example the WM-D6C, as it tends to “flatten” the dynamic range of music. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
AMS: Automatic Music Sensor or Automatic Music Search. This is an arrangement fitted to some Walkman cassette players, such as the WM-EX618, and all Discman compact disc players which allows music tracks to be skipped through automatically. Cassette players use the gaps between the tracks to recognise where each track starts and finishes, and in all but the most sophisticated models can only repeat the current track or skip to the next one. Compact disc players use the digital information on the disc to find the tracks and can skip to any one instantly. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Anti-Rolling: This term has no specific meaning, but describes a tape mechanism that includes measures to reduce the speed changes that can occur when the machine is moved or carried. Sony Walkmans tend to use counter-rotating flywheels for this purpose. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Auto Reverse: This is a mechanical refinement of cassette player design that allows the machine to play both sides of the tape without the listener having to turn it over. In a compact machine like a Walkman, this is done using a special four-track head. Auto reverse greatly increases to complexity of a cassette player so it is usually found only on more expensive models, such as the WM-7. However, the inclusion of auto reverse does lead to some compromises having to be made in the design of the rest of the machine and precludes really accurate adjustment to the deck, so it is not found on serious professional machines such as the TC-D5, WM-D6 or WM-DC2. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
AVLS: Automatic Volume Limiter System. This restricts the maximum sound level that the listener hears through the headphones. It was introduced to counter the claims that personal stereos could damage the listener’s hearing if played too loudly for extended periods. AVLS is a limiter, and retards the volume only if the signal level is excessive. It first appeared on the WM-3000, which was intended for children. Later on it became common across the range, in models such as the WM-EX110. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
BL Skip: Blank Skip. A feature of some Walkmans that makes the mechanism automatically fast forward past blank sections of tape. This feature is an extension of AMS, and is only included on a few well specified models, for example the WM-EX618. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Chrome Tape (IEC type II): Chrome tape is a higher grade than normal ferric tape, and is capable of better high frequency response and lower background noise. It is recorded in a slightly different way to normal tape, so to be played correctly the player must be set for this. Chrome and Metal tapes are played in the same way so some Walkmans have the switch labelled with just one of them, normally Metal. Chrome tape requires more energy to record on, so simple recorders, such as the WM-BF67, cannot use it for recording. Chrome cassettes have extra slots in the back which some players can recognise and adjust themselves automatically, for example the WM-F75. Not all “Chrome” tapes actually use Chromium Dioxide as the recording medium, TDK “SA”, the most popular Japanese brand, uses modified cobalt, though it has similar characteristics to “true” Chrome types such as BASF CR EII. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
CRT: Cathode Ray Tube. A display device used in television sets. Though normally confined to large domestic receivers, skilful engineering allowed Sony to use a CRT in their Watchman televisions, for example the FD-210BE, which gave a superior picture to other pocket sized sets as a result. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Cue/Review: A cassette mechanism that allows fast forward or rewind to be temporarily engaged during playback so the sound can be heard at a much higher speed and at a reduced volume. This is useful for finding a particular passage in a speech programme, and it often found on Walkmans whose mechanical parts were initially designed for use in dictating machines, for example the TPS-L2. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
DBB: Dynamic Bass Boost. See Mega Bass.
DD: Disc Drive. This stands not for “direct drive” but “disc drive”. By the adoption of this special mechanism the wow and flutter performance of a cassette mechanism is dramatically improved, as is its immunity to movement and vibration. These improvements are particularly noticeable in small machines which can only accommodate lightweight, small diameter flywheels if conventional designs are used. A well designed and maintained DD Walkman can give speed stability performance that is difficult to distinguish audibly from CD or LP. A full description of the DD mechanism can be found on the TC-D5 page. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Dolby System: Dolby noise reduction is a proprietary electronic circuit that is used under license. Its function is to suppress the characteristic background hiss present in all tape recordings. It is a two-part process, recordings have to be “encoded” by the recorder and “decoded” by the player. Many better Walkman models, such as the WM-DD2 feature Dolby “B” type noise reduction, it is not fitted to the more basic ones as the parts and the license are both quite expensive. Later, an updated and incompatible system, Dolby “C” was introduced. This was not popular and only appeared on a few models, for example the WM-DC2 and the WM-D6C. The weakness of both systems is that the degree of decoding required is indicated only by the signal strength of the recording. To work properly, this requires that the recorder and player are of identical, standardised performance and kept closely in adjustment. This proved difficult to achieve for mass-produced items like Walkmans and the system does not always improve the overall sound quality of a tape. Often a dull and indistinct sound results if the compatibility is not perfect. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
DX/Local: These terms refer to two levels of radio sensitivity, the former receives all available stations, the latter only the strongest. This function is useful in areas where many broadcasts are receivable as it clears the tuning band somewhat, and for when the set is being used near a powerful transmitter with may otherwise overload it. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Graphic Equaliser: A system of multiple tone controls which each operate on a separate frequency band. The controls are always of the sliding type, and are arranged so that when set the sliders form a pattern that represents the frequency response characteristic of the system. This was a very popular device during the 1980’s and was initially offered for the Walkman user as an add-on unit. Later models offered built-in graphic equalisers, for example the WM-60. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Hot Line: This function allows a person to talk to a Walkman listener without disrupting the playback of to tape. A microphone in the cassette player is switched in by pressing the hot line button and the sound from this is mixed in with the music on the tape, which is faded down at the same time. The microphone signal is not recorded on the tape. The technical term for this is “foldback monitoring”. Only a few Walkman models included this feature, the TPS-L2, WM-3 and WM-R2. In practice, it turned out to be a complex gimmick of little practical use. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
LCD: Liquid Crystal Display. A type of display device that can be made very small and to consume only a small amount of power. They are used in Walkmans and Discmans to provide readouts for digital radio tuners, track time displays etc. Further development led to an LCD that could show a colour television picture, this was used in the GV-S50E Video Walkman. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Logic Controls: Tape transport controls that instead of acting on the mechanical parts directly are electronic switches that instruct a logic circuit, which then operates the motors and solenoids which power the cassette mechanism. This is a complex arrangement, but necessary if complex functions such as AMS or Blank Skip are to be implemented, or if remote control is needed. The first Walkman with logic controls was the WM-7. All Discman compact disc players have logic controls. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Loudness: A type of frequency correction applied in some amplifiers to correct for the non-linearity of human hearing and low volume levels. The first Walkman to offer this was the DD-100. The action of the loudness circuit was difficult to explain to the non-technical customer, so in later models it was given the name “Mega Bass”. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
See also: Mega Bass
Mega Bass: A loudness system that increased the bass sound that a Walkman could provide through small headphones. It worked completely electronically, and adjusted itself depending on the content of the music and the volume control setting. Confusingly, Sony used the same term to describe a similar system in their portable radio cassette models that worked using an extra “sub woofer” loudspeaker. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
See also: Loudness
Metal Tape (IEC type IV): This type of tape was the most expensive standard type and could record even more treble energy than Chrome, at the expense of a slightly higher level of hiss. Like Chrome tape, recordings on it are made in a slightly different way to normal ferric tape, so the playback machine has to be switched to the appropriate setting. Metal tape is very difficult to record on and the only Walkmans that can do it are the WM-D6 and the WM-D6C. Metal tape has the same identification slots as Chrome and so those Walkmans with automatic tape selectors can automatically and adapt themselves to it. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Normal Tape (IEC type I): This type of tape is the most basic and can be used by any tape recorder or player. It uses iron oxide as a recording medium and is often referred to as “ferric”. Pre-recorded cassettes tend to use ferric tape and all Walkmans can play it correctly. Recording on ferric tape requires only a moderate amount of energy and this is the type of tape that should be used in recording Walkmans. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
One Touch Recording: A recording mechanism that can be started by operating one control only, rather than two in combination (e.g. Record and Play). This arrangement makes it easier and quicker to start a recording, but increases the chances of erasing and existing recording by mistake. The WM-R707 offers one touch recording. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
PLL: Phase Locked Loop. A highly stable electronic circuit that can be used in radios to give accurate, drift-free tuning. Though it is not necessarily confined to radios with digital frequency readouts (like the SRF-M32), it has become synonymous with this type of set and is often used to refer simply to a radio with a digital tuning system. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Plug-In Power: A special type of microphone socket that can also be used to power an amplified microphone without the need for extra cables. In Sony equipment, such sockets are usually denoted by a red ring around the outside. The design of the socket means that ordinary microphones can be used as well. Such a socket can be found on many models, including the TC-D3. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Quartz Lock: A quartz crystal is a circuit element that can be used as a very accurate frequency reference. Walkmans use quartz crystals for accurate frequency indication in digitally tuned radios, for example in the WM-F605, and as a tape speed regulator in professional machines such as the WM-DC2. All Discman compact disc players use a quartz crystal as a timing reference too, but as this is universal it is never mentioned. Text copyright © Walkman Central. Unauthorised reproduction prohibited.

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