Audio Database

The

Nakamichi 682ZX
228,000yen(around the 1981 time)

Description
@
The stereo cassette deck developed as a second generation of 680ZX as a single speed machine of only standard speed.
The Dolby NR processor which became independent, respectively was adopted as the sound-recording system and the play system, and the merit of a discrete and 3 head stream compositions is employed efficiently.

The frequency-dispersion type double capstan scheme is adopted as a mechanism part,Since two capstan diameters and a fly-wheel diameter were changed while realizing the stable tapes run and the uniform head touch, it was avoided that the periodicity of a flutter overlaps and it has achieved the reduction of rotation unevenness, and the modification of the modulation noise. Moreover, the ill effect by fine oscillation of the pressure ununiformity of a pad or pad spring material is prevented by equipping a tapes pad lifter.
Furthermore, if the oscillation produced from the body of revolution of a motor or others gets across to a tapes, it will become a cause which makes a flutter increase. In order to reduce this, compared with iron, the big aluminum alloy of a damping characteristics is used as a chassis material, by carrying out the outsert of the resin to this, the fine oscillation was absorbed and the occurrence of the vibration is prevented.

If a control is pushed, a logic circuitry will work, and the operation of a mechanism has the structure of operating mechanism ‚Ç by a control motor.
Not using a solenoid plunger, the scheme which drives a cam by a motor has realized reduction of operation sound, reduction of a tapes or the damage to transport, fall of a temperature rise, and low power-ization.
In order to adopt the PLL servo motor as the main motor, to detect a rotational frequency variation, to compare the signal and phase of a reference-signal oscillator and to control to an exact rotational frequency, the highly precise rotation is realized.

The recording head, the reproducing head, and the erase head have adopted as a head the discrete 3 head scheme completely separated on the structure.
The P-8L type is adopted as the reproducing head. The loss which takes place by the narrow gap of 0.6 micron by adopting the lamination core of Krista Roy at the time of a play was prevented, and the frequency characteristic extended to 22kHz is realized. Furthermore, the form which loses a low-pass surge (contour effect) is taken, and the play [ flat / to super-low-pass one ] is realized. Moreover, the endurance of 10,000 hours or more is realized by adopting the special form which abolishes the •ÐŒ¸‚è event of a core.
The R-8L type is adopted as the recording head. The reproducing head serves as the same a 3.5-micron gap with the lamination core of Krista Roy. Moreover, special form was adopted also as this head and the endurance of 10,000 hours or more is secured like the reproducing head.
The E-8L type is adopted as the erase head. They are the ferrite core which was excellent in the RF property, and a double gap type which uses a sendust core with high flux density at a leading end.

The double NF circuitry which applies the negative feed back to an electrolytic capacitor is adopted as a sound-recording equalizer circuitry, a playback-equalizer circuitry, and an output line amplifier circuitry. The direct-current stabilization is attained at the same time it suppresses low distortion which this generates by a capacitor.
Moreover, a sound-recording equalizer, the recording head and the reproducing head, and a play equalizer amplifier are linked directly, respectively, a coupling capacitor is eliminated, and a modification of a property, such as preventing a phase shift the distorted modification at the time of a play and low-pass, is aimed at at the time of a sound recording.

The auto calibration functionality is carried and azimuth adjustment and a coordination of a sound-recording regeneration level can carry out that it is simultaneous and automatically by one calibration operation.
Azimuth adjustment starts a coordination by pushing the Auto Cal button and the Play button from a sound-recording pause. By a 400Hz testing tone being recorded and played first, detecting the phase difference of a right-and-left channel, and the signal being sent to operational amplifier, and controlling a motor, the lever connected with the belt through the gear is moved, and the tilt angle of the recording head is adjusted. If an azimuth gap is lost, the phase difference will also be lost, a motor stops, and a coordination is completed.
A start-up of azimuth adjustment will also start level adjustment simultaneously. The signal with which the 400Hz testing tone was reproduced is detected through buffer amplifier, and is added to a comparator. It is compared with a reference signal by the comparator, and a motor rotates according to the voltage difference, the connected slide volume for calibrations is operated, and the signal current (recording level) of the recording head is changed. When a play Output voltage changes by this and it becomes equal to reference level, a motor stops and a coordination is a completion.
Coordination time is about 6 seconds also including azimuth adjustment, and the error serves as a span of }0.5dB. Moreover, an adjustable range is }2.5dB from a base value, and the usual tapes for musics is covered enough.

The bias regulating function which can adjust a bias current to a value suitable for a using tapes is carried.
This coordination is adjusted looking at the indicated value which appeared in the level meter by sound-recording play of a 15Hz (-20dB) testing tone. At this time, the indicated value of a level meter is expanded by 20dB so that it may be easy to adjust.
The volume for a coordination is prepared a tapes selector exception and according to the right-and-left channel, and the adjustable range has become EX position (normal system)}4.5dB, SX position (CrO2 system)}3dB, and ZX position (metal tape)}6dB.

In addition to the Dolbey B type NR, the Dolbey C type NR with the higher noise reduction effect is carried as noise reduction.
It has the same principle of operation as B type fundamentally, and the Dolbey C type NR is making two noise reduction processors of a high-level stage and row level stage take charge of 10dB at a time, it is total and has realized a noise reduction of a maximum of 20dB.
Moreover, by C type, the slide band scheme which carries out variable to frequency which starts operation input level according to a frequency component is adopted, and the bleeding event called "a noise breathes" is suppressed.
By a Dolby NR switchpoint, a switchover of C type / B type / off is possible.

- Carry the wide-range peak level meter of function-logic-diagram display device which displays 40dB - +10dB by 24 segments.

The RAMM functionality which can select and pull out the head of one favorite music out of the music recorded by the tapes is carried.

If the easy queuing functionality is carried and a pause button is pushed into FF/Rew, speed can be downed to abbreviation 1/3, and the description of a sound recording can be heard. Furthermore, if it continues pushing a FF/Rew button, about 1/of speed falls to 5, and can pull out the head of music easily.

If the Rec mute functionality is carried and the Rec button is further pushed during a sound recording, only while continuing pushing, an input signal is omitted and a silent sound-recording part can be made.

The MPX filter is built in.

A timer sound-recording play is possible by using an audio timer.

An optional remote Control unit can be used and can be operated from the distant location.

Mechanism
Discrete
Sound-recording
Reproducing
Recording
Erase

Rating of a mode
Form Stereo cassette deck
Head Recording head: R-8L
Reproducing head :P -8L
Erase head: E-8L
Tape speed 4.8cm/s
Wow and flutter 0.04% or less Wtd rms
0.08% or less Wtd peak
Frequency characteristic (a recording level of 20dB) 20Hz-22kHz}3dB (ZX tapes)
20Hz-20kHz}3dB (SX, EXII tapes)
A comprehensive S/N ratio (IHF A-Wtd rms, 400Hz, 3%) Dolby C on: 72dB or more (70 microseconds, ZX tapes)
Dolby B on: 66dB or more (70 microseconds, ZX tapes)
A comprehensive distortion (400Hz, 0dB) 0.8% or less (ZX tapes)
1.0% or less (SX, EXII tapes)
Cancellation ratio 60dB or more (1kHz, 0dB)
Channel separation 37dB or more (1kHz, 0dB)
Crosstalk 60dB or more (1kHz, 0dB)
Bias frequency 105kHz
Input sensitivity/impedance 50mV / 50kohm
An Output voltage/impedance
(Output level maxima)
Line: 1V (400Hz, 0dB) / 2.2kohm
Headphone: 45mW (400Hz, 0dB)/8ohm load intensity
DC output only for a black-box series }10V or 125mA maxima
Power source AC100V, 50Hz/60Hz
Power consumption A maximum of 36W
Dimensions Width 482x height 143x depth of 340mm
Weight About 9kg
Option Wired remote control RM-200 (2,000yen)