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  • Analog

    The recording and playing of sounds in real time. The flow of information is continuous


    Certain frequency and amplitude considerations necessitate that output signals from records, tapes and microphones be processed to deliver a signal to deliver a signal to the amplifier that will accurately reproduce the original sound. This item performs this processing.


    Increasing and subsequent decreasing of certain frequency and amplitude ranges.


    A magnet created by the induction of an electrical flow through iron.

    Print Through

    Adjacent layers of spooled magnetic tape, if too thin, may have the magnetic imprint of one layer transferred to the adjacent layer, called this.

    Pre-Groove Echo

    If one groove on a record lies too close to an adjacent groove, the phono stylus may receive a portion of the signal from the adjacent groove.

    Tape Head

    A magnet across which the magnetic tape is pulled. Three functions are performed by tape heads: 1) erasing previous magnetic imprints, 2) recording, and 3) playing back.

    Erase Head

    The tape head that precedes the record head to remove any signal previously recorded on the magnetic tape. This is done by high frequency alternating current that randomizes the magnetic patterns on the tape.

    Tape Noise

    White noise created by the magnetized, randomized, iron oxide particles on magnetic tape. Full tape erasure cannot be obtained because as the tape passes the head at any given moment, some randomized magnetized particles are in alignment with the playback head. The random voltage fluctuation produced by these particles passing the tape head produce noise. This noise limits how small a signal's amplitude may be recorded.

    Playback Head

    The tape head that sends a signal to the amplifier by varying its magnetic field in accordance with a recorded signal that is passed across its gap on tape.

    Record Head

    The tape head that receives a signal from an amplifier and produces variations in its magnetic field, thus magnetizing a portion of the oxide coating on the recording tape as it passes across its gap.


    The path that is recorded on magnetic tape.

    Quarter track head

    Tape heads that produce four separate tracks. In most machines with these, tracks 1 and 3 are played while the tape runs forward, and when the tape's direction is reversed, tracks 2 and 4 may be played. However, a machine may be configured so that all four tracks are used in the same direction simultaneously.

    Signal-to-noise ratio

    The amount of amplitude difference between the level of noise on a tape, and the recorded signal. The greater, the better.


    The standard that is used for circuitry in tape machines to increase and subsequently decrease the amplitude of certain frequencies in order to restore inherent frequency losses in tape recording.

    Bias Current

    Inaudible ultra high frequencies introduced to the tape recordings process to improve the fidelity of problematic audible frequencies and amplitudes usually masked by tape noise, an inherent condition of magnetic recording tape.

    Automatic Gain Control

    Circuitry added to smaller tape recorders that automatically boosts an audio signal if it is below a certain pre-specified level, or automatically lowers it if the signal is too high.

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