LUXMAN C-8f

Commentary

As a power amplifier driver, it is a control amplifier that uses ODNF circuit and 4-row Altimemate volume.

A flat amplifier with the same circuit configuration as the power amplifier M-8f is equipped with a control amplifier that increases the acoustic energy to the level that drives the power amplifier.

With sliding volume as the theme, we pursued the problem of volume control from every point of view and adopted the developed ultimate volume.
The ultimate volume with 4-row brass machined parts for a fully balanced circuit configuration has achieved high precision and low distortion with a maximum attenuation of -120dB and an interlocking error of ± 0.5 dB or less (0 ~ -90dB).

The ODNF circuit is used to achieve a fast initial slew rate that captures the instant the sound rises and to unify the tone quality of the entire band from low to wide range. This circuit consists of a main amplifier, which is a non-NFB amplifier, and a sub amplifier, which amplifies only the difference between the input and output waveforms. The distortion component for cancellation amplified by the sub amplifier is sent to the main amplifier.
For the C-8f, we have developed an ultra-wide-band, high-slew rate, low-distortion circuit that does not require phase correction for the amplification circuit part of the music signal, eliminating the phase correction that cannot be avoided with the conventional negative feedback circuit (NFB). We also focused on the nature of NFB, feeding back only the distortion component from the output to the final stage of the amplification circuit, removing only the distortion component from the output waveform, and separating the NFB method from the music signal. By separating the NFB method from the music signal, we have achieved a high initial slew rate and ultra-wide bandwidth.
In addition, the NFB circuit eliminates the DC servo amplifier for ultra-low frequency control, which causes unnatural coloring in the low frequency range, and the tone color of all bands is unified.

The C-8f uses a fully balanced amplifier configuration and the power supply system of the S. T. A. R. circuit that clarifies high-grade parts and the amplification reference point to bring out the true value of the balanced amplifier.

High-inertia power supply is used for the power supply section.
By installing a special electrolytic capacitor with excellent instantaneous discharge characteristics, we have created an environment in which we can always pool a wide range of power sources, minimizing delay control, and enabling dynamic power supply which is important for amplifier circuits.

To prevent unwanted vibration and noise, the chassis uses a box isolation structure.
Based on a 5-point FRP chassis base with excellent vibration absorption mode, parts are firmly fixed in a thick chassis to suppress vibration.
In addition, the power transformer, electrolytic capacitor, and amplifier block are laid out so that they do not interfere linearly with each other. In addition, each block is shielded by a shield plate, and the internal filter is strengthened to eliminate interference from flux and noise.
In addition, the power supply section is separated by a partition structure and connected to the main body chassis by semi-floating processing using an independent power supply room power supply room system, the power supply section is isolated both electromagnetically and mechanically to prevent leakage flux.

Custom-made parts exclusively for Luxman are used for each part.
The resistor is based on an acoustically excellent carbon film resistor, and has been studied in a wide range of fields, including selection of alumina as a body porcelain, etching, carbonization, terminal material, terminal shape, and press-fitting method.
In addition, the power transformer, electrolytic capacitor, copper Styrofoam capacitor, copper bus bar, and high-purity cable are all custom parts.

A new "gain-1" position has been established for the main volume in consideration of combination with multi-channel audio equipment such as home theater processors.
You can supply the audio level of each channel set by the processor, etc. without losing balance.

The input terminals are equipped with a coaxial Line 5 and two balanced systems, and the outputs are equipped with two coaxial systems and two balanced systems. Both balanced and unbalanced connections are also possible for bi-amplifier drive.
There are also two input / output terminals for the sound recorder.
When the balance input is normal, pin 3 is positive, pin 2 is negative, and pin 1 is ground.

Equipped with a line phase sensor that senses the polarity of the AC power supply.

Model Rating

Type	Control amplifier
Input Sensitivity / Input Impedance	CD/DVD-A, CD/SACD, Line1, 2, 3 : 250mV/50k Ω Balance Line1, 2 : 250mV/100k Ω
Output / Output impedance	Coaxial : 1V/300 Ω, 7.5 V maximum (rating) Balance : 1V/600 Ω, Maximum 7.5 V (Rating)
Total harmonic distortion factor	0.005% or less (rated)
Frequency characteristic	20 Hz ~ 20000 Hz + 0 -0.1 dB 10 Hz to 100000 Hz + 0 -2.2 dB
Signal-to-noise ratio	119 dB or more (IHF-A)
Tone control	Treble : Turn over 3 kHz Max ± 8 dB (10 kHz ± 6 dB) Bass : Turn over 300 Hz Max ± 8 dB (100 kHz ± 6 dB)
Accessory function	Tape dubbing : 2 systems (1 → 2, 2 → 1) REC OFF Straight Switch Output Selector Output phase selector switch Stereo / mono selector switch Remote (Power) output Line phase sensor
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	23W (regulated by Electrical Appliance and Material Control Law)
External dimensions	Width 467x Height 187x Depth 475 mm
Weight	22.5kg