LUXMAN C-9

Commentary

A control amplifier that inherits development concept, circuit technology, construction and finish from Top Endomo Dell C-10.

It uses the Ultimate volume that was developed as a sister model of the Super Ultimate Attenuator adopted in the C-10.
In the Ultimate Volume, by improving the sound quality and accuracy of the sliding continuous variable resistor, we have obtained high performance such as an interlocking error within ± 0.5 dB (0 ~ -90dB) and a maximum attenuation of -120dB or less.
For this volume, we have developed and adopted a new carbon composite that enables high-density distributed coupling as a material for resistors that determine sound quality. This material has an extremely low specific resistance component of the material itself and provides a uniform carbon layer, thus realizing an ideal resistor plate that does not contain any irregular R components other than resistors.
In addition, in the conventional volume, when observed at the micro level, there were irregularities and gaps in part of the distribution of carbon particles, and unstable contact resistance was generated in this area, causing distortion and noise such as the third harmonic wave. This problem becomes more pronounced in the contact resistance between the resistor and the brush. Therefore, in the C-9 Ultimate Volume, the surface of the resistor plate is mirror-finished, making contact conditions with the brush more advantageous. This finish is not dependent on polishing treatment, and a special treatment is used to ensure mirror-finished surfaces, and a light surface finish achieves extremely high-quality contact surfaces.
In addition, 80 0.1 φ multi-wire brushes are used to make contact with the resistor plate. These brushes are laid out linearly along the entire width of the resistor. The contact point with appropriate contact pressure and gold-plated tip enables pure signal processing without current distortion.
In order to cope with mechanical vibration, which tends to be a particularly harmful factor in the case of sliding type, it has a robust structure from the structure such as the shield case made by scraping from solid brass to the mechanical part such as the 8 φ brass shaft rotating shaft made of the same material. Especially, oil-containing metal is used for the bearing part composed of 2 point support, and high accuracy without clear balance and backlash is achieved. In addition, the problem of magnetostriction is relieved by the adoption of non-magnetic brass material.

A fully balanced CSSC circuit is used for the flat amplifier section.
The CSSC circuit is a single-staggered circuit with pure complimentary service configuration directly connected to all stages. Since it is a circuit with excellent phase characteristics, stable operation is realized with minimum compensation.
In the C-9, this circuit is placed on the hot / cold line and the two amplifiers are driven under the same condition. This eliminates the problem of potential difference and time phase difference caused by the amplification reference point. In addition, a buffer amplifier of the complimentary service configuration is inserted at the input to the CSSC circuit to feed the signal to the fully balanced CSSC circuit at high speed while maintaining high input impedance.

It is equipped with an OD β circuit to unify all bands with natural sound quality.
The C-9 uses a CSSC circuit to dramatically improve DC stability. Moreover, by refining the bare characteristics of the circuit to a high degree, it is possible to eliminate the DC servo amplifier. In the NFB of all bands, the optimum feedback amount is set for each circuit, and by controlling the energy balance of all music bands, natural musical expression power is obtained.

A unique high-inertia power supply is used for the power supply.
In a typical power supply circuit, stabilization was achieved by NFB. However, the power supply voltage was constantly fluctuating due to the time difference between the real time of music and the feedback until the control was activated. Moreover, at a point slightly away from the feedback point on the time axis, the fluctuation became large, which had a significant effect on the music signal.
In the high-inertia power supply, the concept itself of stabilizing the power supply by NFB control of the conventional voltage is changed. The power supply energy is saved by a unique large-capacity custom electrolytic capacitor with excellent instantaneous discharge capability, and a sufficient margin is provided for it, so that constant energy is always maintained without depending on NFB control.

The power supply section uses a custom capacitor developed for the high-inertia power supply.
The ideal high-inertia power supply is not only capable of storing a large amount of electric charge, but also excellent in instantaneous response performance, with as low output impedance as possible in all frequency ranges, and with little influence of the character of the part itself on sound quality.
In LUXMAN, we have succeeded in tuning a special instantaneous charge / discharge capacitor for audio equipment through joint development with a capacitor manufacturer. By satisfying the conflicting requirements of large capacity and high response, we have achieved a high-inertia power supply.

An independent power supply room system is adopted. By storing power transformers, rectifier diodes, block capacitors, etc. in a power supply room independent of the chassis structure, it not only blocks leakage flux, but also isolates mechanical vibration from the main chassis with vibration-proof material. This structure cuts off electromagnetic and mechanical noise sources and eliminates external influences.

The chassis structure is a high rigidity construction with a large mass FRP base.
Weight class 5-point installation By mounting each part with the bottom structure of the FRP base and the thick and hard chassis material, the influence of unnecessary vibration and resonance is shielded.

High-quality custom parts are used abundantly, and small capacity condenser, copper foil Styrofoam condenser with copper shield, and sealed gold-plated contact relay used for switching signal system are custom-made products of LUX special specification.

It is equipped with a coaxial Route 6 and two balanced systems for input, and two coaxial and two balanced systems for output. Either coaxial or balanced can be selected for bi-amplifier drive.
It is equipped with two tape input / output systems, and the balance / unbalance conversion amplifier for recording output uses a newly developed hybrid IC chip to achieve high-precision conversion.
In addition, metal type XLR terminals are used for the balance connection terminal, and materials with high reliability and durability are used.

Equipped with an inverted switch for switching between hot and cold at the balanced input.

Equipped with a reverse mode switch for exchanging L/R for output.

Equipped with NF type tone control.

It is equipped with a line straight switch that bypasses the tone control and balance circuit.

It uses an aluminum machined extra-thick front panel with a special pearskin surface finish.

The version upgrade service from C-9 to C-9II was provided, and the version upgrade of the flat amplifier board was possible.

Model Rating

Type	Control amplifier
Input Sensitivity / Impedance	Tuner, CD, Line1-4 : 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	110 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 475 mm
Weight	22.0kg
Sold Separately	Upgrade to C-9II (¥ 200,000)