Technics SU-C7000

Commentary

A control amplifier that uses a battery-driven power supply.

It uses the newly developed battery drive bi-class AA Advanced System.
In this method, the AC power supply and signal circuit are completely separated by using battery power, eliminating noise loops between devices through the power supply and switching noise of the power supply circuit.
One package contains a large-capacity small sealed lead-acid battery, which is used as a backup power source for the main arithmetic unit of a large computer. The battery can be fully charged for approximately four hours. When the remaining battery capacity is low, it is detected and automatically switched to the rectified AC mode. At the same time, the battery starts charging. When charging is completed, it is switched back to battery power.

Newly developed resistor rotating volume is used for the volume.
This volume is based on the inverse concept of the conventional volume. It has a structure in which the brush is fixed and the resistor is rotated. This reduces the number of dissimilar metal joints that cause sound quality degradation by half. In addition, fine particles of carbon are specially blended in the resistor, which greatly affects sound quality. Free electrons flow smoothly through the carbon particles, greatly reducing distortion.
Furthermore, in order to reduce external vibration transmitted to the brush, the brush is placed in a gold-plated case made by die-casting zinc with a high specific gravity thoroughly improve sound quality.

The chassis structure uses a multi-layer Technics Hybrid Construction Base (THCB).
In this structure, the hard rubber base is sandwiched between the bottom chassis of the copper-plated steel plate and the chassis of the steel plate, and the top chassis of the copper-plated steel plate is stacked on top of the hard rubber base to achieve excellent vibration damping characteristics.
In addition, it uses a 2.8 mm thick top plate and bulk mold compound with consideration for electromagnetic radiation, a φ 60 mm large insulator with wool felt attached, and a side wood with a real wood mirror finish to prevent vibration from the outside.

In order to eliminate the leakage flux generated by the conventional rectangular core transformer, we have adopted an R-core transformer with a circular cross section structure. In this transformer, since the coil is tightly wound around the circular core, uniform magnetic flux is formed and leakage flux and loss can be reduced.

Each input / output terminal is equipped with one balanced type.
This terminal uses a balanced transformer system with a DL-type permalloy core and reduced unbalance. It is carefully shielded so that it is not affected by external magnetism and provides stable transmission.

The newly developed MASTER series high-quality large aluminum electrolytic capacitor is used.
In this capacitor, aluminum oxide formed on the surface of aluminum foil is used as an insulating layer, and electric charge is extracted not by electronic conduction but by ionic conduction of electrolytic solution, and mechanical properties are also improved by using newly developed special damping aluminum for the case.

Equipped with a balance volume with an ON/OFF switch.

Equipped with an AC/DC operation changeover switch.

Equipped with a battery voltmeter with AC/DC/Charge display.

The relay uses a gold-clad contact relay sealed with nitrogen gas.

Uses a very thick PC-OCC power cord with polarity display.

Six NOFC wires are used for internal wiring.

The printed circuit board is a glass-epoxy gold-plated board.

Model Rating

Type	Control amplifier
Total harmonic distortion rate (20 Hz to 20 kHz)	Phono MM (Rec out, EIAJ) : 0.001% Line1/2, CD, tape1/2 : 0.001%
Signal-to-noise ratio	Phono MM:86dB(EIAJ) 88dB(IHF'66) Line1/2, CD, tape1/2 : 97 dB (EIAJ) 104dB(IHF'66)
Frequency characteristic	Line1/2, CD, tape1/2 : 20 Hz to 20 kHz + 0 -0.1 dB) 0.5 Hz ~ 125 kHz (+ 0 dB, -3dB) Balance : 30 Hz to 20 kHz ± 0.3 dB Phono RIAA deviation : 20 Hz to 20 kHz ± 0.2 dB
Rated output	Pre out : 1 V (20 Hz to 20 kHz, 0.001%)
Maximum allowable input	MM:100mV
Pwer	100 VAC, 50Hz/60Hz
Power consumption	32W
External dimensions	Width 483x Height 134x Depth 375 mm
Weight	17.5 kg (including battery power supply)
Sold Separately	Replacement Battery Drive Power Supply LC-R2212X2AU (2x12V, 2.2Ah/20HR) (Repair parts, production to order, ¥ 19,800)