Stereocheck Reviews:

Luxman C-900u: A classic preamplifier with clear, smooth and neutral sound

The previous top-of-the-line preamplifier, the C-800F, was released back in 2007 and pioneered the use of the LECUA1000 precision attenuator for volume control. To increase durability and eliminate...

Luxman C-900u
Luxman C-900u

The previous top-of-the-line preamplifier, the C-800F, was released back in 2007 and pioneered the use of the LECUA1000 precision attenuator for volume control. To increase durability and eliminate dielectric effects in audio circuits, the conductors on the board are coated with a 100 micron thick layer of gold. The preamplifier circuit contains only selected resistors and capacitors corresponding to high-tech products. Preamp gain increased to 12 dB (C-800F had 9.5 dB). A new material is used for the input and output RCA connectors – a copper alloy, combining the hardness of brass and the conductivity of copper. The body, weighing almost 20 kg, sits on massive gradient mounts that protect the electronics from unwanted vibrations.

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The Luxman C-900u uses a fully balanced circuit topology based on discrete elements. The amplification circuits include four balanced modules that provide precise channel separation while also minimizing various noise and interference. To suppress high-frequency distortion, the latest generation ODNF feedback loop (version 4.0) is used, which is coupled with a Darlington circuit that increases the current gain. The power supply contains a powerful transformer and four electrolytic capacitors with a capacity of 3300 μF. Of particular note is the improved version of the LECUA 1000 high-precision attenuator, which features 88-step volume control ranging from 0 to 87 dB. Moreover, the high signal-to-noise ratio and low level of distortion are maintained at any volume level. Luxman uses its own efficient technology to produce circuit boards with thick gold-plated copper foil traces.

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The Luxman C-900u preamplifier has a solid all-metal body with smooth corners and anti-vibration cast iron feet. The front panel has a FL display with built-in LED operating mode indicators and clear symbols, the size of which can be increased using the Zoom button on the aluminum remote control. To the right of the display is a balance control, a button to switch between balanced and normal outputs, a pass-through activation key for an external AV processor/preamp, and a volume knob. On the left are the HF and LF tone adjustment knobs, the Line Straight button, which bypasses the tone block, an input selector and a key for switching to standby mode.

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The rear panel of the Luxman C-900u has the following inputs: 3 balanced (XLR), 3 unbalanced (RCA) and an RCA pass-through for connecting an external AV processor/preamplifier. Outputs: two RCA and two XLR, allowing bi-amping connection. There is also a power switch and two sockets for controlling components connected to the preamplifier.

The Luxman C-900u is in the big league with exceptionally clear, smooth, transparent and neutral sound, precision volume control and carefully selected premium components. The device combines perfectly with the branded M-900u terminal.

Luxman C-900u Specifications

Input Sensitivity/Input Impedance 255 mV/43 kΩ (RCA), 255 mV/86 kΩ (XLR)
Output Voltage/Output Impedance 1 V (Max: 11 V)/90 Ω (RCA), 1 V ( maximum: 22.5 V)/180 ohms (XLR)
Frequency response 20 Hz – 20 kHz (+ 0, – 0.1 dB), 5 Hz – 120 kHz (+ 0, – 3 dB)
Harmonic distortion 0.009% (RCA , 20 Hz – 20 kHz), 0.005% (XLR, 20 Hz – 20 kHz)
Signal-to-noise ratio 123 dB (RCA), 126 dB (XLR)
Tone control range Bass: ± 8 dB (100 Hz), Treble: ± 8 dB (10 kHz)
Inputs 3 line RCA, one RCA pass-through for external AV processor/preamp, 3 balanced XLR
Outputs 2 line RCA, 2 balanced XLR
Other switching 2 sockets for controlling connected components, ground terminal
Remote control RA-20
Network cord with OFC copper conductors available
Power consumption 42 W; 2.2 W in standby mode
Dimensions (WxHxD) 440x130x430 mm
Weight 19.7 kg