The Yamaha K-2000 was a high-performance stereo cassette deck released in 1982, combining a direct-drive two-motor transport, three-head configuration, automatic recording calibration, dbx and Dolby B noise reduction, electronic tape-position counter and extensive automated transport functions. Yamaha designed the K-2000 around its Linear EM Transduction system, which was intended to reduce distortion within the recording path and preserve a more linear relationship between the incoming electrical signal and the magnetic signal recorded onto tape.
At the centre of the Yamaha K-2000 was Yamaha’s Linear EM, or Electro-Magnetic, Transduction system. A conventional cassette deck could introduce distortion through the inductive and capacitive characteristics of its recording circuit, including the record-head winding and bias-trap circuitry. Yamaha’s approach removed the conventional bias trap from the signal path and isolated the bias oscillator’s circuitry from the recorded audio signal.
The recording amplifier used a dual-differential FET-input direct-coupled design connected directly to the recording head. This arrangement was intended to improve linearity and reduce intermodulation distortion throughout the recording process. Yamaha extended this approach by using a high bias frequency of 200kHz to reduce the possibility of interference between the bias oscillator and the recorded audio signal.
The Yamaha K-2000 used a two-motor direct-drive transport. The capstan was driven directly by a pulse-servo brushless direct-drive motor developed specifically for the application. Directly coupling the motor shaft to the capstan removed the need for belts within the capstan drive and reduced the speed variation that could result from belt movement, ageing or mechanical irregularities.
A separate flat-torque DC motor drove the reel system. By separating the reel and capstan functions, changes in reel rotation and tape supply could not directly affect capstan speed. This arrangement helped the transport maintain stable tape movement throughout recording and playback.
The deck’s wow and flutter was specified at less than 0.02% WRMS and less than ±0.08% weighted peak under DIN 45507 measurement. Fast-forward or rewind time for a C-60 cassette was specified at approximately 75 seconds.
The Yamaha K-2000 incorporated a three-head system with a three-laminate-core, low-impedance Sendust recording and playback head. The laminated construction was intended to reduce eddy-current losses and improve high-frequency performance. Sendust was selected for its magnetic properties and resistance to wear.
Separate recording and playback elements allowed the recorded signal to be reproduced immediately after it had been placed onto the tape. This permitted direct comparison between the source signal and the recorded result during recording, rather than requiring the cassette to be rewound before the result could be checked.
The erase system used double-gap Sendust main and sub erase heads. These formed part of the K-2000’s monitoring erase function, which allowed unwanted recorded material to be erased while the operator monitored the tape. The additional erase arrangement distinguished the K-2000 from the related K-1000, which used a conventional erase head.
Recording calibration was handled by Yamaha’s α-ORBiT system, with ORBiT standing for Optimum Record Bias Tuning. Magnetic tapes of the same basic formulation could vary between manufacturers and even between different tape models from the same manufacturer. These variations could affect the ideal recording bias and level settings required for accurate performance.
The α-ORBiT system automatically calibrated the deck each time a new cassette was loaded and the Record/Pause control was selected. The process took approximately two seconds and did not leave a calibration tone on the tape. The system adjusted the recording conditions to suit the characteristics of the cassette before recording began.
The calibration sequence included determining the tape formulation through the cassette shell identification openings, erasing a short test section, recording test signals and reading the results through the playback head. The microprocessor then adjusted the required recording conditions before returning the transport to the selected recording position.
The Yamaha K-2000 supported normal, chromium dioxide and Metal tape formulations. Its automatic tape-detection system recognised the cassette shell identification openings and selected the appropriate basic operating category before α-ORBiT completed the finer calibration process.
The deck was fitted with both dbx and Dolby B noise reduction. Yamaha used separate processing systems so that a recording encoded with one system could be monitored through the appropriate playback decoding circuit during recording.
Dolby B noise reduction was specified to provide a signal-to-noise ratio better than 68dB. With noise reduction bypassed, the specified signal-to-noise ratio was better than 59dB. With dbx engaged, the specified signal-to-noise ratio increased to better than 108dB.
The dbx system compressed the programme’s dynamic range during recording so that low-level material remained above the tape’s inherent background noise. During playback, the signal was expanded by a corresponding amount, restoring the original dynamic relationship while reducing the audible contribution of tape noise.
The combination of dbx encoding and decoding gave the Yamaha K-2000 a specified dynamic range exceeding 100dB. Dolby B remained available for compatibility with recordings made using the more widely adopted Dolby system.
Frequency response with normal tape was specified at 20Hz to 18kHz within ±3dB and 20Hz to 19kHz within ±6dB. With chromium dioxide tape, response extended from 20Hz to 20kHz within ±3dB and from 20Hz to 21kHz within ±6dB.
Metal tape frequency response was specified at 20Hz to 20kHz within ±3dB and 20Hz to 21kHz within ±6dB. Maximum recording level for normal, chromium dioxide and Metal tape was specified at +8dB, while overall distortion was rated at less than 0.8%.
The front panel included a 4-digit linear real-time counter with minus indication. Rather than providing only a relative mechanical indication, the counter used microprocessor control to calculate the amount of tape passing through the transport.
The counter could continue below zero and display negative values when the tape was moved beyond the selected reference point. The system measured reel rotation and compensated for the changing winding diameter of the cassette reels, allowing a more consistent indication of tape position than a conventional mechanically driven counter.
Automatic and memory functions were integrated with the counter and transport. Dedicated controls were provided for reset and memory operation, while the transport included electronically controlled play, record and pause, rewind, fast-forward, stop, mute and monitor functions.
The Yamaha K-2000 also included automatic repeat, timer recording and timer playback facilities. These functions allowed the machine to perform unattended operations when used with suitable external timing equipment.
Recording level was adjusted through a horizontal sliding control marked from 0 to 10. A separate record-balance control allowed the relative level of the left and right channels to be adjusted, while the fluorescent display provided independent indication of both channels.
The peak-level display used a calibrated scale extending from low signal levels through 0dB and into the positive recording range. Separate left and right indications allowed channel balance and peak recording levels to be observed during setup and recording.
A pitch control provided adjustment of playback speed, while an MPX filter was included for recording FM broadcasts containing multiplex pilot components. The filter could be switched out when it was not required.
Front-panel monitoring controls permitted selection of source or tape signals. The three-head arrangement allowed the operator to monitor the recording directly from the tape, making it possible to assess the results of the α-ORBiT calibration and recording-level adjustments while recording was in progress.
A front-panel headphone socket was provided with its own adjustable level control. The specified headphone output was 170mV into 8 ohms, while the line output was specified at 500mV with an impedance of 30k ohms.
Line input sensitivity was specified at 50mV, with a maximum allowable input of 6V and an input impedance of 50k ohms. The K-2000 was designed to match the supply voltage and mains frequency of the region in which it was sold.
The Yamaha K-2000’s front panel reflected the electronically controlled nature of the deck. The cassette compartment occupied the left side, while the digital counter, calibration indicators, noise-reduction selectors, transport controls and fluorescent meters were grouped across the centre and right-hand sections.
Its black finish, recessed control areas and horizontally arranged buttons gave the K-2000 a restrained appearance despite the number of functions available. Much of the operating system was controlled through rectangular electronic keys rather than large mechanical levers or rotary controls.
The Yamaha K-2000 combined mechanical stability, automatic calibration and extensive electronic control within a single cassette deck. Its pulse-servo direct-drive capstan motor, separate reel motor, laminated Sendust head assembly, α-ORBiT calibration, monitoring erase system, double dbx and double Dolby B processing and linear real-time counter placed it among Yamaha’s most advanced cassette recorders of the early 1980s.
Features
- Yamaha Linear EM Transduction recording system
- Dual-differential FET-input direct-coupled recording amplifier
- 200kHz bias oscillator frequency
- Three-head recording and monitoring configuration
- Three-laminate-core low-impedance Sendust recording and playback head
- Double-gap Sendust main and sub erase heads
- Monitoring erase function
- Pulse-servo brushless direct-drive capstan motor
- Separate flat-torque DC reel motor
- α-ORBiT automatic recording bias and level calibration
- Automatic tape-formulation detection
- Support for normal, chromium dioxide and Metal tapes
- Double dbx noise-reduction processing
- Double Dolby B noise-reduction processing
- Four-digit linear real-time tape counter
- Minus counter display
- Microprocessor-controlled tape-position calculation
- Source and off-tape monitoring
- Electronic transport controls
- Record mute function
- Automatic and memory transport functions
- Timer recording and playback operation
- Automatic repeat function
- Fluorescent left and right peak-level display
- Sliding recording-level control
- Separate recording-balance control
- Playback pitch adjustment
- Switchable MPX filter
- Front-panel headphone socket with level control