The Marantz SD9000 was a top-of-the-range stereo cassette deck introduced in 1982. Known as the Compudeck, it combined a two-speed, three-head recording system with microprocessor-controlled programme selection, electronic timing functions and a dual-motor transport. Its unusually broad control set placed it among the most technically elaborate domestic cassette decks offered by Marantz during this period.
Unlike conventional cassette decks restricted to the standard speed of 4.75cm/s, the Marantz SD9000 could also operate at 9.5cm/s. Doubling the tape speed increased the amount of tape used for a recording but allowed the machine to exploit a wider frequency response and reduce some of the limitations associated with the compact cassette format. A prominent speed selector on the front panel allowed operation at either speed, making the Marantz SD9000 suitable for conventional cassette compatibility or higher-speed recording.
The three-head arrangement used separate record, playback and erase heads. This configuration allowed the recorded signal to be monitored from the tape immediately after it had passed the record head. The front-panel monitor selector provided switching between the incoming source and the recorded tape, enabling direct comparison while recording. Separate heads also allowed the recording and playback circuits to be optimised for their individual functions rather than sharing a combined record and playback head.
Tape movement was handled by two DC servo motors, with separate motor functions used within the transport system. The transport was controlled by solenoid-operated, feather-touch logic keys rather than mechanically linked piano-style controls. Electronic control allowed the transport to interact with the deck’s microprocessor, timer and programme-selection systems while also reducing the physical effort required to change operating modes.
A major feature of the Marantz SD9000 was its computer-controlled programme system. The Compudeck circuitry could identify recorded selections by detecting the silent spaces between them and could be programmed to locate and play selected tracks in a chosen sequence. The programme section included numbered selection keys, a programme display and controls for entering, checking and clearing the programmed order.
The programme-selection system extended beyond simple track skipping. The Marantz SD9000 could search through the cassette, locate programmed selections and control the transport according to the entered sequence. This gave cassette playback a degree of automated access that was unusual before digital disc formats made direct track selection commonplace.
The front panel also incorporated an electronic timer with a digital display. This system supported timed recording and playback, with settings entered through dedicated hour and minute controls. Timer memory and cancellation functions were provided, while a sleep function allowed the deck to be incorporated into a timed listening arrangement. The timer could operate with the transport controls to begin a recording or playback operation at a selected time.
A four-digit electronic tape counter replaced the simpler mechanical counters used on many contemporary decks. The counter could be reset and used with memory functions to assist with locating recorded positions. Counter and programme information were presented through illuminated numerical displays positioned across the central control section.
Recording controls included independent left and right microphone input levels, a master recording-level control and separate output adjustment. The microphone and line inputs could be mixed, allowing microphone signals to be combined with a connected line-level source during recording. Two front-mounted microphone inputs were provided, together with a headphone connection for private monitoring.
The Marantz SD9000 supported standard ferric, ferrichrome, chromium dioxide and Metal cassette formulations. Separate tape selectors allowed the recording and equalisation circuits to be configured for the chosen tape type. A continuously adjustable bias fine control provided additional optimisation within the selected tape position, although the machine did not provide the complete multi-stage calibration systems later used on some cassette decks.
Noise reduction was provided by Dolby B. The Dolby circuit could be selected independently for recording and playback as required, reducing audible tape hiss when used with recordings encoded through the same system. Some versions of the Marantz SD9000 were also offered with dbx noise reduction, but this was a distinct regional or model variation and was not fitted to every Marantz SD9000.
The metering system used two large illuminated analogue meters for monitoring the left and right channels. These displayed recording and playback levels, with additional peak indicators positioned above the meters. The combination of analogue indication and peak warning lamps helped the operator establish appropriate recording levels while monitoring short-duration signal peaks.
Additional transport facilities included automatic tape-slack removal, automatic stop protection and full logic control of play, record, pause, fast-forward and rewind. Reel movement was monitored electronically as part of the transport-control system. When rotation ceased at the end of the tape, the control circuitry stopped the mechanism rather than allowing the transport to remain engaged.
The Marantz SD9000 used the wide, low-profile styling associated with Marantz components of the period. Its brushed-metal front panel was divided into distinct operational areas for the cassette transport, programme controls, timer, metering and recording adjustments. The large number of illuminated buttons and displays reflected the extent to which its transport and operating functions were controlled electronically.
The internal design incorporated dedicated playback equalisation, recording-current, recording-compensation, bias-oscillator and erase-oscillator circuits. Separate circuit assemblies were used for the preamplifier, programme selector, control logic and timer functions. This made the Marantz SD9000 considerably more complex than a conventional manually controlled cassette deck.
The Marantz SD9000 represented an attempt to expand the compact cassette beyond straightforward sequential recording and playback. Its two-speed transport addressed the format’s performance limitations, while its computerised search, programme and timer functions anticipated features that later became familiar on digital audio equipment. Its combination of three heads, dual-speed operation and extensive electronic control made it one of the most distinctive cassette decks in the Marantz range.
Features
- Two-speed cassette transport operating at 4.75cm/s and 9.5cm/s
- Separate record, playback and erase heads
- Two DC servo motors
- Solenoid-operated feather-touch logic transport controls
- Microprocessor-controlled Compudeck programme-selection system
- Programmable playback sequence
- Automatic search for recorded selections
- Electronic timer for automatic recording and playback
- Timer memory and sleep functions
- Electronic four-digit tape counter
- Source and tape monitoring
- Independent left and right microphone-level controls
- Microphone and line-source mixing
- Master recording-level control
- Bias fine adjustment
- Support for ferric, ferrichrome, chromium dioxide and Metal tapes
- Dolby B noise reduction
- Illuminated analogue level meters with peak indicators
- Automatic tape-slack removal
- Electronic end-of-tape detection and automatic stop
- Front-panel headphone and microphone connections