Nakamichi 700ZXE

Commentary

This is a cassette deck that has almost completely inherited the basic performance of the 700 ZXL while simplifying its functions.

Equipped with an auto-calibration function that automatically adjusts the recording head azimuth, bias current, and recording / playback level according to the tape to be used.
In the auto-calibration operation, first set the normal (EX), chrome (SX), and metal tape (ZX) tape selectors and the playback equalizer for 120 μ s (normal) and 70 μ s (chrome and metal) according to the type of tape to be used. From the recording standby state, press the Play button while holding down the auto-calibration button to perform the adjustment in the same flow as the flowchart.
The adjustment starts with recording and playback of a 400 Hz, 15kHz-20dB signal, and the bias adjustment adjusts the bias current so that the 15 kHz output is equal to the 400 Hz signal. The recording and playback level changes slightly by changing the bias current, so this process is repeated once again to complete the adjustment. When the adjustment is complete, the tape is rewound to the starting position of 0000 and stops.
During adjustment, the display panel will blink. When the adjustment is completed, it will go off. The EX, SX and ZX tape position lamps selected by the tape selector will light. When the adjustment range is exceeded, the tape stops running and the tape position lamp will blink.

The bias current and recording / playback level data adjusted by auto-calibration are stored in memory until the next adjustment operation is performed to prevent data from being lost when the power is turned off during timer recording.

Equipped with RAMM (Random Access Music Memory).
Unlike the 700 zxl RAMM, the 700 ZXE RAMM has a function of passing up to 9 songs and calling up and selecting the desired song. This is a method of detecting a blank between songs of 3 to 4 seconds.

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.

A double-NF circuit is used for the equalizer circuit of the reproduction amplifier to stabilize DC and reduce distortion.
(There is no direct connection between the playhead and the first stage amplifier as was done in the 700 zxl.)

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.

Equipped with a display to confirm information such as auto-tuning, 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.

Remote control unit RM-200 was sold separately.
With RM 200, you can perform tape operations, including automatic RAMM music selection, as well as Rec mute and queuing 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 characteristic (with auto-calibration)	20 Hz to 20 kHz ± 2 dB (18 Hz to 23 kHz ± 3 dB) (Nakamichi EX, EX II, SX, ZX tape, recording level -20dB)
Overall S/N ratio (70 μ s, ZX Tape, 3% THD, IHF-A, rms)	Dolby B NR in : 66 dB or more (400 Hz) Dolby C NR in : 72 dB or more (400 Hz, using NR-100)
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-300 (¥ 28,000) Dolby CNR Unit NR-100 (¥ 29,800)