SONY TC-KA7ES

Commentary

As a reference model of the New ES series, this is a cassette deck with a thoroughly refined circuit, configuration and device.

The capstan motor adopts a direct drive system using a 3-phase BSL motor with less uneven rotation.
In addition, we have reduced wow and flutter by adopting a closed-loop dual capstan system in which the tape is sandwiched between two sets of capstan and pinch rollers to suppress modulation noise.

The Lapis (sapphire capstan base) system, which uses sapphire with high hardness and low friction coefficient for the bearing of the capstan motor, maintains stable running accuracy over a long period of time.
Especially in the TC-KA7ES, it is used not only for the take-up side but also for the supply side capstan.

Equipped with Dolby S NR as a noise reduction system. With the introduction of Dolby SR technology used in professional equipment and precise signal processing, tape noise is reduced to approximately 1/16.
In addition, the breathing phenomenon characteristic of NR is suppressed by finely controlling the pitch and pitch of sound.

The TC-KA7ES uses an R-core transformer for the power supply. The TC-KA7ES uses an independent R-core transformer for the control system and the audio system. In addition, the shielding case is filled with resin to suppress magnetic flux leakage and vibration.

The layout of the audio circuit follows the signal flow as much as possible, and the recording amplifier and the reproducing amplifier are integrated on independent boards to prevent interference.

The FB chassis is used for the chassis structure. Metal material with sufficient strength and thickness is used. The frame surrounding the outer circumference and beams passed in front and back are used to firmly fix the whole chassis as one box. Moreover, by combining members of different shapes and sizes, natural vibrations are mutually cancelled, and vibration of the chassis as a whole is greatly reduced.
In addition, TC-KA7ES is plated with copper to suppress electromagnetic noise.

High quality and pure transmission are achieved by using single-crystal oxygen-free copper ESC-OCC wire with a purity of 99.997% or more throughout the circuit.

It uses an eccentric insulator with the mounting hole to the chassis offset from the center. External signals are mutually cancelled, making it difficult for them to be transmitted to the chassis. The position and diameter of the hole are also examined through trial production and trial listening. The hole is tuned so as to be effective in attenuating mid - and high-frequency vibration components that affect audibility.
In particular, TC-KA7ES uses an eccentric insulator made of cast iron with superior vibration resistance.

We have adopted a 6N wound laser amorphous head that uses 6N material with 99.9999% purity for the winding of the laser amorphous head.
In addition, the shield case is gold-plated in order to eliminate the weak vibration that the head receives.

The cassette half is equipped with pads for pressing the tape against the head, but the closed-loop dual capstan system has a problem that this extra pressure increases modulation noise.
In order to solve this problem, we have adopted a pad pressure reduction mechanism that releases the pressure of the pad by providing a slight convex projection above and below the head gap.

TC-KA7ES reduces beat noise and intermodulation distortion by increasing the bias frequency up to 210 kHz.

By mounting a buffer amplifier to lower the output impedance just before the output terminal, it is difficult to be affected by the superiority of the pin cord used for connection with the amplifier.

It uses a midship drive system with a heavy power transformer and mechanical deck in the center of the chassis and a control circuit and audio circuit on the left and right sides. It is stable and resistant to external vibration because the weight is balanced on 4 feet.

A rigid half-hold mechanism is adopted to prevent vibration and sound pressure directly applied to the cassette half.
In addition to the cassette holder made of fine ceramic composite material with high vibration resistance and the cassette stabilizer made of sorbocein with excellent vibration resistance, the cassette holder has been changed to a dual lock that locks the cassette holder from one side to both sides. In addition, to ensure the effectiveness of the cassette stabilizer, the tape is fixed more securely by the delayed-action stabilizer mechanism, in which the stabilizer is pressed against the half after the cassette lid is closed.

Equipped with Dolby HX-PRO.
By controlling the bias current in units of one thousandth of a second according to the frequency and level of the signal, linearity in the high-frequency range is maintained.

A 3-point REC calibration function with a built-in oscillator is installed to realize recording that takes advantage of the capabilities of tape.
The adjustment by the internal oscillator, which used to be 2 points, has been expanded to 3 points of 400Hz/3kHz/15kHz, making it possible to more precisely match the characteristics of the tape.

Equipped with FL linear counter with subtraction function.

It has an auto monitor function that automatically switches the monitor sound from source to tape when you press the play button.
Manual switching is also possible.

It is equipped with a multi-AMS function that can start up 30 tracks before and after the track being played.

There are 2 color variations, gold and black.

Wireless remote control is included.

Model Rating

Type	Cassette deck
Format	4-track 2-channel
Heads	Erase : 1 Recording : 1 Play : 1
Motor	Linear Torque BSL D. D. Motor : 1 DC Motor : 2
Signal-to-noise ratio	57 dB (EIAJ, Dolby NR off, Metal Tape) 80 dB (Dolby NRS, Peak Level, Metal Tape, Acoustic Compensation)
Frequency characteristic	15 Hz ~ 22 kHz ± 3 db (EIAJ, -20dB recording, metal tape) 15 Hz ~ 16 kHz ± 3 db (-4dB recording, metal tape)
Wow and flutter (EIAJ)	± 0.04% Wpeak 0.022%WRMS
Distortion Factor (EIAJ)	1.3% (3rd harmonic distortion rate, reference recording level of 250nWb/m, 315 Hz sine wave, metal tape)
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	27W
External dimensions	Width 430x Height 135x Depth 380 mm
Weight	Approx. 12 kg
Attachment	Wireless Remote Control RM-J701