TEAC A-7400RX

Commentary

This is a 2-track 38 cm master recorder which inherits the A-7400 mechanism and amplifier circuit and is equipped with the dbx system Type-I developed for business use.

A dbx system (Decilinear noise reduction system) is installed as a noise reduction system.
In the dbx system, the dynamic range of the input signal is compressed to 1/2 in decibels for recording, and when it is played back, it is expanded to twice and restored to its original value. Thus, a dynamic range of more than 100 dB can be easily achieved with an ordinary tape recorder.

In order to improve the mounting accuracy of impedance rollers, tension arms, heads, etc. that play an important role in the tape running system, we have adopted a die-cast base that has undergone high-precision processing and does not change over time.

The impedance roller with excellent dynamic balance absorbs uneven tape travel and wow / flutter, resulting in smooth tape travel. In addition, the oil-dump-type tension arm provides constant, stable tension, smooth start-up, and prevents sound skipping.

By shortening the distance between the capstan and the head and between the heads, and by taking the optimum touch angle between the tape and the head, modulation noise is reduced.

The counter-roller combined with the tension arm that keeps the winding angle of the tape constant prevents uneven running of the tape.

A DC servo electronic commutator motor is used for the motor of the running system.
The DC servo electronic commutator motor is driven at 24 V and electronically controlled by a servo detection circuit to keep the rotational speed constant at all times. In addition, there is no mechanical contact at all, eliminating noise caused by friction and performance degradation caused by wear.

The operation of the mechanism is controlled by a logic circuit using an IC. Since there is no mechanical contact such as relay, highly reliable mode operation is possible.
In addition, the direct function method is adopted, and free operation such as direct PLAY from FF/REW is possible.
In addition, it is also possible to make a follow-up recording that enters the recording mode in the middle of playback.

Equipped with a peak level meter with a scale range of -40dB to + 5 dB. An electronic circuit with a response time of 10 ms is used to handle pulse sounds with short duration, enabling accurate indication.

Equipped with four microphone inputs, two microphones can be set for each L/R channel, and 2-channel mixing recording with four microphones is possible. Also equipped with two line inputs for each L/R channel, and line-to-line mixing recording is possible.
Mixing recording of 2 lines of microphone and line is also possible.

The power supply voltage of the microphone amplifier is as high as 45 v, and the voltage utilization factor is increased by the combination of PNP-NPN transistor and direct coupling and dynamic margin is greatly improved.

In order to prevent distortion of the microphone amplifier due to excessive input during on-microphone operation, an L/R independent microphone attenuator with 20 dB attenuation is used.

Equipped with a record master volume, all input levels can be controlled by a single volume.

Memory marker with Klix/Klukš top is mounted on input volume.
When you turn the volume to a preset position, you can check the position by clicking stop.

It has a queuing mechanism so that when you push the cue lever up in fast-forward mode, you can monitor the sound so you can see the beginning of a song or where you want to edit, or when you put it into a playback pose so that the tape touches the head so you can manually rotate the reel to check the exact edit position.

Equipped with an editing mechanism. When the switch is turned ON and a PLAY operation is performed, the take-up reel stops and the tape is sent out.

An opening and closing type head housing mechanism is adopted.

Equipped with pitch control, tape speed can be changed within ± 5% range.

It is equipped with a linear counter that can read the tape running amount with the terminal of minute second.
The accuracy of the counter is within ± 1.5%.

Uses a high hardness permalloy head.

Equipped with dbx encoded output terminal.

Equipped with dbx decode copy mechanism.

Equipped with MPX filter.

It is equipped with a 3-step tape selector independent of bias and equalizer.

Equipped with a real-time pause mechanism.

Equipped with a 4-track playback head.

Equipped with an output volume that click-stops at a precise reference level.

Equipped with a memory auto-stop mechanism that stops at the preset counter position when rewinding.

Timer recording / playback is possible by using the timer sold separately.

There was a full remote control mechanism sold separately.

Model Rating

Type	Tape deck
Track format	2 tracks, 2 channels 4-track, 2-channel playback
Heads	4-head
Reel	17 Type, 26 Type
Tape speed	38, 19 cm
Motor (3 motors)	For Capstan : Direct Drive / DC Servo Motor For Reel : Eddy Current Induction Motor
Wow and flutter	38cm:0.04% wrms 19cm:0.05% wrms
Frequency characteristic	38 cm : 25 Hz to 30 kHz 19 cm : 25 Hz to 28 kHz
Signal-to-noise ratio	60 dB (3% THD level, WTD) 100dB(dbx in)
Distortion factor	0.8% (reference level) 0.4%(dbx in)
Stereo separation	50dB 70dB(dbx in)
Input	Mic : 0.25mV/-72dB (Applicable Microphone : 600 Ω or More) Line : 0.1V/50k Ω
Output	Line : 0.3V/10k Ω or more Headphone : 8 Ω
External dimensions	Transport : 470 mm wide x 455 mm high x 300 mm deep Amplifier : 470 mm wide x 205 mm high x 310 mm deep
Weight	Transport : 27.5 kg Amp : 12.5 kg
Sold Separately	Remote Control Unit RC-170 (¥ 10,500) Timer Control Adapter RC-350 (¥ 9,500)