The JVC DD-99 was introduced in Japan in 1981 and subsequently offered in export markets as a high-performance three-head stereo cassette deck. It combined a quartz-locked direct-drive capstan system, electronically controlled transport, microprocessor-based B/E/S tape tuning and separate recording and playback head elements. The JVC DD-99 was designed to optimise recording conditions for individual cassettes while maintaining stable tape movement and allowing the recorded signal to be monitored directly from the tape.
The transport is based around JVC’s double-servo quartz-locked direct-drive capstan motor. A Hall element developed by JVC is used for polarity switching, permitting a brushless motor construction without mechanical contacts. The motor is also coreless and slotless, reducing rotational irregularities and mechanical noise while allowing a compact drive system.
An FG servo system monitors capstan rotation using an integrated 204-pole, 102-pulse detector. The FG magnet is mounted coaxially with the capstan and magnetised after its centre position has been established, helping reduce detection errors caused by positional displacement. Quartz control is introduced after the transport has reached operating speed, allowing a controlled start before the higher-stability quartz-lock circuit takes over. A front-panel Quartz Lock indicator confirms when regulation has been established.
The capstan assembly of the JVC DD-99 uses a bridge-drive circuit intended to reduce the influence of component variation and temperature changes on rotational accuracy. Composite materials are employed within the flywheel structure to suppress vibration and modulation noise. JVC specified weighted RMS wow and flutter at 0.019 per cent, with a weighted peak figure of ±0.045 per cent.
Tape tension is controlled by an eddy-current loop system. A rotating disc associated with the take-up reel faces a flat magnetic disc connected to the supply side. Their opposing movement produces eddy-current braking, helping maintain consistent tape tension as the cassette moves from the beginning towards the end of its reel. The mechanism also removes the conventional tension pad used by some three-head transports, reducing friction within the tape path.
The cassette holder of the JVC DD-99 was engineered to minimise movement of the cassette shell while the deck is operating. The head slide base uses a four-point zinc die-cast construction intended to resist twisting and deformation. Together with the non-contact back-tension arrangement, this provides controlled tape contact with the head assembly and reduces changes in alignment over extended use.
The JVC DD-99 uses separate recording and playback head elements within a combined head assembly, together with a dedicated erase head. The recording element is a Sen-Alloy design, while playback is handled by an X-cut Sen-Alloy head. The playback head uses specially shaped Sendust material to reduce low-frequency contour effects while maintaining extended high-frequency response. A two-gap Sen-Alloy erase head completes the three-head system.
JVC’s Sen-Alloy construction bonds a Sen-Alloy chip to the tape-contacting surface of a laminated Permalloy core. This structure was intended to provide high magnetic saturation, accurate head gaps, resistance to wear and compatibility with metal tape. Different gap widths could therefore be used for recording and playback rather than requiring one head gap to perform both functions.
The three-head arrangement of the JVC DD-99 provides direct off-tape monitoring during recording. The user can compare the incoming source with the signal reproduced immediately from the cassette, making it possible to assess recording levels, noise-reduction operation and the results of the automatic tape-tuning process while recording is taking place.
A central feature of the JVC DD-99 is its B/E/S tuning system. B/E/S represents bias, equalisation and sensitivity, with a microcomputer controlling all three parameters to suit the cassette being used. Rather than applying a fixed adjustment for each general tape category, the system records and evaluates test signals to establish settings for the individual tape.
When the tuning process is started, the microcomputer searches through 16 bias steps and establishes an averaged setting. Equalisation is evaluated through 16 high-frequency steps at 12.5kHz and eight mid-frequency steps at 4kHz. High-frequency measurements are recorded repeatedly and averaged, with left and right channels adjusted independently. Recording sensitivity is also measured and compensated independently for each channel.
The complete B/E/S tuning cycle takes approximately 30 seconds. Once calibration has been completed, the tape rewinds automatically to the position at which the process began. The calibrated response is specified at 40Hz to 12.5kHz within ±1dB for metal, chrome-equivalent and normal tape formulations.
The amplifier sections use a DC configuration intended to reduce the number of coupling capacitors within the audio path. The head amplifier employs a directly coupled double-differential design, while the microphone amplifier, recording amplifier and noise-reduction circuits also use DC amplifier configurations with positive and negative power supplies. This approach was intended to reduce phase changes, distortion and noise associated with unnecessary capacitors.
Noise-reduction facilities include ANRS and Dolby B compatibility together with Dolby C. Dolby C uses a two-stage sliding-band system in which the operating frequency changes according to signal level. The wider operating band provides increased noise reduction across the middle and upper frequencies while also improving high-frequency recording linearity. An MPX filter is included for recording FM broadcasts containing a stereo pilot signal.
The JVC DD-99 uses full-logic transport controls, allowing operating modes to be selected electronically. The solenoid-controlled mechanism provides direct access to play, record, pause, stop, fast forward and rewind without requiring a fixed mechanical operating sequence. A C-60 cassette can be wound from one end to the other in approximately 90 seconds.
Recording and playback levels are shown by a two-colour fluorescent dot-matrix display with 18-segment indication. The display can be switched between peak and VU operating modes and includes a peak-hold facility for retaining maximum signal readings. Separate microphone and line input controls are provided, together with recording balance and output-level adjustment.
A four-digit fluorescent electronic counter derives its information from magnetic changes detected at the take-up reel. Two memory positions can be stored, allowing the transport to return automatically to selected locations and repeat a chosen section. The counter can also be switched for stopwatch-style time measurement.
Additional facilities include automatic cueing for locating recorded sections, memory-controlled automatic rewind and timer standby for unattended recording or timed playback when used with an external timer. A remote-control terminal accepts the optional JVC R-50 wired remote controller. Headphone level is linked to the playback output control.
The Japanese-market JVC DD-99 operated from a 100V AC supply and consumed 37W. Regional export versions were configured for their respective mains supplies. The deck’s substantial motor, transport and calibration systems were contained within a chassis measuring 435mm wide and weighing approximately 7.4kg.
Features
- Separate Sen-Alloy recording and X-cut Sen-Alloy playback heads
- Two-gap Sen-Alloy erase head
- Double-servo quartz-locked direct-drive capstan motor
- Eddy-current tape-tension stabilisation system
- Microprocessor-controlled bias, equalisation and sensitivity tuning
- Independent left and right channel tape calibration
- ANRS, Dolby B and Dolby C noise reduction
- Two-colour fluorescent peak and VU level display
- Four-digit electronic counter with two memory positions
- Full-logic electronic transport control