LUXMAN C-7i

Commentary

A control amplifier with improved SN ratio to support the next generation format.

A fully balanced CSSC circuit is used for the circuit configuration.
In the CSSC circuit, a grounded base type current transmission stage is adopted in the second stage, and the cut-off frequency is set high enough to realize natural signal amplification without extra phase correction. In the C-7i, this CSSC has been developed into a fully balanced CSSC circuit configuration, and the performance of the balanced configuration circuit is brought out by taking advantage of the characteristics of the CSSC circuit with a clear amplification reference point.

Uses Luxman's original OD β circuit.
In general amplifier circuits, NFB can be divided into AC and DC regions. The DC region is relatively difficult to control and requires stronger correction than the AC region. For this reason, methods such as DC servo amplifiers have been used to improve correction. However, only in the low frequency region related to the DC region, colorization of sound quality occurs, resulting in inconsistency of sound quality with the middle and high frequency region.
In the OD β circuit, DC stability is ensured without using a DC servo amplifier by refining the bare characteristics of the circuit. By using the same correction method for all bands, uniform tone quality is obtained over all bands.

A unique high-inertia power supply is used for the power supply.
In this system, we have developed a large-capacity special electrolytic capacitor with extremely excellent instantaneous discharge characteristics to keep a loose power supply in the power supply section at all times and minimize delay control, which enables a natural power supply for the amplifier circuit.

Exclusive parts for Lux's custom-made audio are used.
In C7i, we have newly developed and adopted an ultra-low-noise custom-made audio resistor that improves reproducibility at the minute level by improving information density. This resistor is based on an acoustically excellent carbon film resistor. We have improved the amount of information transmitted by examining a wide range of matters including selection of alumina, which is a body porcelain, etching, carbonization, terminal material, terminal shape, and press-fitting method.

It uses a large mass FRP chassis base of 5-point grounding excellent in vibration absorption mode, and vibration noise is reduced by firmly fixing parts to a thick hard chassis.
In order to reduce internal and external interference noise, we have reviewed the internal structure and finished the layout so that it does not directly interfere with each other. In addition, each block is shielded by a shield plate and the internal filter is strengthened to eliminate interference of flux and noise.

An independent power supply room system has been adopted. The power supply section is separated by a partition structure, and semi-floating processing has been adopted for connection with the main body chassis. By this system, leakage flux can be completely shut off in the same case by isolating both electromagnetic and structural.

It is equipped with an internal filter to cut off noise from digital devices such as personal computers, power supply noise, radio waves, etc., reducing the influence of peripheral devices.

The input terminals are equipped with a coaxial Line 5 and two balance systems, the output terminals are equipped with two coaxial and two balance systems, and two tape input / output systems are also installed.

Model Rating

Type	Control amplifier
Input Sensitivity / Impedance	Tuner, CD, Line1-3 : 150mV/50k Ω Balance Line1/2 : 150mV/100k Ω
Output Level / Impedance	Co-axial : rated 1V/300 ohm 7.5 v max. Balance : Rated 1V/600 Ω 7.5 v max.
Total harmonic distortion factor	0.005% or less (rated)
Frequency characteristic	20 Hz ~ 20 kHz + 0 -0.1 dB
Signal-to-noise ratio	114 dB or more
Tone control	Treble : Turnover 3 kHz, max ± 8 dB, 10 kHz ± 6 dB Bass : turnover 300 Hz, max + / - 8 dB, 100 Hz + / - 6 dB
Attachment	Tape Dubbing 2 Systems (1 → 2, 2 → 1) Rec off Straight-through switch Output mode selector switch Remote (Power) output Line phase sensor Output phase selector switch
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	38W (Electrical Appliance and Material Control Law)
Maximum external dimensions	Width 467x Height 187x Depth 435 mm
Weight	18.0kg