Nakamichi 700ZXL

Commentary

This is a cassette deck with high performance and improved operability with a variety of functions.

Equipped with an A. B. L. E. (Azimuth, Bias, Level, Equalizer) auto-calibration processor that allows you to set the azimuth, bias, level, and equalizer to suit your tape.
For automatic adjustment of the A. B. L. E., set the tape selector for normal (EX), chrome (SX) and metal tape (ZX) and the playback equalizer for 120 μ s (normal) and 70 μ s (chrome and metal) according to the tape to be used. The automatic adjustment is performed according to the flow of the flowchart when the adjustment instruction is given by the operation button.
In automatic adjustment, the recording playback level and the recording head azimuth are adjusted by recording and playback of a 400 Hz test tone, then 400 Hz and 15 kHz test tones are recorded and played back at -20dB, and the bias current is increased or decreased so that the output levels are equal. This operation is repeated again, then 7 kHz test tone is recorded and played back, and the recording equalizer is adjusted according to the output level. When the adjustment is finished, the tape is automatically rewound to the position of the tape counter 0000.
During adjustment, the display panel flashes and lights when the adjustment is completed. When the adjustment range is out of range, all characters flash.

You can store all the data of the conditions except for the azimuth adjusted by A. B. L. E., including the position of the tape selector, as well as the playback equalizer position (70 μ s/120 μ s) and whether the Dolby NR in/out or external noise reduction is used.
Save can be stored in any position on the A/B/C/D of the Tape Memory button at the end of adjustment.

It is equipped with RAMM (Random Access Music Memory), an automatic music selection system of up to 30 songs using code memory.
The RAMM records track order addresses encoded by a microcomputer during recording, then reads these code signals during playback and plays them according to the programmed track order. The code signals can be recorded either automatically by blanking between tracks or manually at the desired position. Up to 15 points can be encoded and up to 30 songs can be played in memory (repeat) mode.
It also records the playback equalizer position (70 μ s/120 μ s) set at the time of recording, and whether the built-in Dolby B Type NR in/out or external connection noise reduction is used. This eliminates the need to operate the equalizer switch or Dolby NR switch when playing back tapes containing RAMM M code.
Since the code signal uses a low frequency of 5 ± 0.1 Hz in opposite L/R phase, it does not affect the playback sound.

When recording a code signal by automatic operation of the RAMM function, if there is a silent part (blank) of 2 seconds or more, it is detected, and address code signals of 1 to 15 are recorded automatically.
In addition, when recording a code signal manually, it is possible to record a code signal between songs or at a desired position in a song, so that only one part of a song can be repeated.
You can also record manually during recording with automatic operation.

The head part uses Nakamichi's unique discrete three head configuration, and the recording head, reproducing head, and erasing head are completely separated from each other in structure, enabling accurate azimuth adjustment.
A read head and a recording head are placed in the center window of the cassette, and an erase head is placed in the left side small window. Both are placed between the double capstan, and the stable tape tension ensures head touch with no spacing loss.

A P-8L-type playhead is used as the playhead.
This head uses a laminated crystalline core and is compact. In addition, the narrow gap of 0.6 microns eliminates many losses during playback, enabling ultra-high-frequency playback. In addition, the shape eliminates low-frequency waviness (contour effect), enabling ultra-low-frequency flat playback.
In addition, it adopts a special shape that eliminates the phenomenon of unbalanced core, ensuring a long life of more than 10,000 hours (Nakamichi experimental value).

The recording head uses an R-8L catalogue sound head.
As with the reproducing head, it uses a laminated core made of crystalline material with a gap of 3.5 microns. This gives high coercivity and sharp critical zones when using high-density tapes. In addition, even when a large bias current is applied, there is no magnetostriction or saturation, making it possible to record high MOL (maximum output level) from low to high range.
This head also uses a special shape to ensure a lifetime of more than one man-hour, just like the read head.

E-8L-type erase head is used for the erase head.
This head is a double-gap type with Sendust with high magnetic flux density in the front and ferrite core with excellent high-frequency characteristics in the other parts.

The mechanism section incorporates Nakamichi's know-how, such as a frequency-distributed double capstan and a resonance braking chassis.

The capstan uses a frequency-distributed double capstan system to achieve stable tape travel and uniform head touch. The two capstan diameters are 3 mm on the supply side and 2.5 mm on the take-up side. By changing the diameters of the flywheels, the overlap of flutter cycles is avoided, rotational unevenness is reduced, and modulation noise is improved.
In addition, it is equipped with a tape pad lifter to prevent adverse effects due to uneven pad pressure and slight vibration of pad spring material.

The chassis uses a resonance damping type chassis.
This chassis is made of aluminum alloy, which has a larger damping property than iron, and resin is out-plated to absorb microvibration and prevent resonance.

A tape control by C-MOS logic is adopted for the mechanical control, and the cam is driven by a motor.
Compared with the plunger-driven type, this type has a very small sound at the time of operation. Moreover, damage to the tape and the tape transport is reduced because it can contact the tape softly. It also has features such as low temperature rise inside and low power consumption.

A PLL servo motor is used as the main motor.
This motor detects rotational speed fluctuations and controls the rotational speed to an accurate value by comparing the phase with the reference signal, enabling high-precision rotation.

The playback amplifier is directly connected between the playback head and the first stage amplifier, and the equalizer circuit uses a double NF circuit to stabilize DC and reduce distortion.

In the recording equalizer amplifier, the final stage amplifier is directly connected to the recording head, and a double NF circuit is used to reduce distortion during recording. The recording input can be mixed with a 3-point microphone input of L/R / Blend (center) and a line input. A subsonic or MPX filter can be used.

It has a built-in Dolby B type noise reduction system.

Equipped with an extra terminal, a separately sold noise reduction system can be connected.
To use external noise reduction, switch the NR switch on the ceiling panel.

Equipped with LED peak level meter.
The level range of the Conometer is 50 dB (-40db to + 10 dB), and the peak level and peak hold can be displayed simultaneously using a bar graph with 30 segments on one channel. The peak hold is displayed for approximately 6-7 seconds and then reset.

Equipped with a 4-digit digital tape counter.
This counter can count from 0000 to 9999 in the positive direction and to -999 in the negative direction. Memory playback / stop can be performed in conjunction with the memory switch.
The count is directly connected to the reel axis to perform precise pulse detection, minimizing errors.

It is equipped with a display to confirm information such as A. B. L. E., noise reduction status, RAMM, etc.

It is equipped with queuing mechanism which can change speed in 2 stages.

Equipped with a RecMute mechanism that can make a silent recording part.

Built-in 400 hz test tone.

Timer recording / playback is available.

Equipped with a high-output headphone port.

There was a remote control unit sold separately.
The RM-300 can handle all tape operations, including RAMM operations, and has a 4-digit digital display tape counter.
RM-200 allows for remote control of normal tape operations except RAMM operations.

Model Rating

Type	Cassette deck
Truck type	4-track, 2-channel stereo system
Heads	3 heads (1 erase, 1 record, 1 play)
Motor (for tape drive)	For Capstan : 1 PLL servo motor For Reel : 1 DC Motor
Tape speed	4.8 cm / sec
Wow and flutter	0.04% or less Wrms 0.08% or less Wpeak
Frequency characteristics (using A. B. L. E)	20 Hz to 20 kHz ± 1.5 dB (18 Hz to 24 kHz ± 3 dB) (Nakamichi EX, EX II, SX, ZX tape, recording level -20dB)
Overall S/N ratio (70 μ s, ZX Tape, IHF-A, rms)	Dolby B NR in : 66 dB or more (400 Hz, 3% THD) Dolby C NR in : 72 dB or more (400 Hz, 3% THD, NR-100 used)
Total Distortion Factor (400 Hz, 0 dB)	0.8% or Less (ZX Tape) 1.0% or Less (SX, EX II tape)
Erasure rate	60 dB or More (100 Hz)
Channel separation	37 dB or More (1 kHz, 0 dB)
Bias frequency	105kHz
Input	Line : 50mV/50k Ω Mic : 0.2mV/10k Ω NR : 100mV/50k Ω
Output	Line : 1 V (400 Hz, 0 dB, maximum output level) Headset : 45 mW (400 Hz, 0 dB, maximum output level) NR : 100mV/2.2k Ω
Pwer	100 V, 50/60Hz
Power consumption	50W max.
External dimensions	Width 500x Height 262x Depth 250 mm
Weight	Approximately 14 kg
Sold Separately	Remote Control Unit RM-200 (¥ 6,000) Remote Control Unit RM-300 (¥ 28,000) Dolby CNR Unit NR-100 (¥ 29,800)