Luxman M-900u: Another masterpiece from Japanese engineers

Luxman M-900u is characterized by openness, purity, rich natural highs and mids, deep dense bass and a wide voluminous...

Luxman M-900u
Luxman M-900u

The Luxman M-900u stereo power amplifier is another masterpiece from Japanese engineers at Luxman. The design of the model is made in the style of minimalism: clear and smooth lines, an understandable control system and massive gradient supports that protect the device from unwanted vibration – this is what you can notice at first glance at the model.

Aesthetically, the Luxman M-900u power amplifier is made in a laconic retro style. The model boasts impressive power ratings, as well as the ability to work with any acoustic systems.

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The Luxman M-900u amplifier has a massive 48-kilogram case with a front aluminum panel, which has two arrow level indicators with original white LED backlighting. On the facade there is a power/standby button with an indication of operating modes, an input selection button with two LEDs, a backlight off button and an LED diode indicating the activation of the BTL bridge mode. The amplifier chassis does not use a ground loop, which can introduce parasitic interference and noise. The case has excellent damping and rests on gradient cast-iron legs that effectively dampen resonances and vibrations. The

Luxman M-900u power supply is equipped with four capacitors with a capacity of 20,000 μF and a powerful transformer (1250 VA), the windings of which are made using wires with a rectangular cross-section. A thick busbar made of purified OFC oxygen-free copper runs from the power supply to the output stages. The device develops a power of 150 W per channel at 8 Ohm, 2 x 300 W at 4 Ohm and can operate in the BLT bridge mode, delivering 600 W (8 Ohm). Up to 12 W, the Luxman M-900u operates in class A. The Luxman M-900u amplifier has a damping factor of 710 units and is not afraid of load impedance drop down to 1 Ohm.

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Each channel of the amplifier has one block with four parallel push-pull amplification circuits. Darlington circuits and proprietary ODNF negative feedback technology (version 4.0), developed specifically to suppress distortion, are used. Premium-class components are used in the circuits.

There are two inputs on the rear part of the amplifier – balanced and unbalanced. One of the connectors of each input can be used to connect the Luxman M-900u in monoblock mode (bridge), for switching to which the corresponding “slider” is used. For balanced connectors, there is a switch that inverts the phase. There is a port for connection via the system bus and a ground terminal. For connecting the speaker system, the power amplifier is equipped with two pairs of massive screw terminals.

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The amplifier’s sound is characterized by openness, exceptional purity, naturalness, rich natural highs and mids, deep dense bass and a wide voluminous stage. The model will be an excellent companion for working in tandem with the Luxman C-900u preamplifier.

Luxman M-900u Specifications

Nominal output power 2 x 150 W (8 Ohm); 2 x 300 W (4 Ohm); 600 W (8 Ohm) in bridged mode (mono)
Peak output power 2 x 1200 W (1 Ohm); 2400 W (2 ohms) in bridged mode (mono)
Input voltage 1.24 V (180 W, 8 ohms)
Gain 29 dB
Input impedance 34 kOhm (XLR), 51 kOhm (RCA)
Frequency response 20 Hz – 20 kHz (+ 0, – 0.1 dB), 1 Hz – 130 kHz (0, – 3 dB)
Total harmonic distortion less than 0.008% (1 kHz, 8 ohms), less than 0.1% (20 Hz – 20 kHz, 8 ohms)
Signal-to-noise ratio 117 dB
Damping factor 710
Inputs balanced XLR (with phase switch), unbalanced RCA
Other switching system bus socket, ground terminal Speaker
output 2 pairs of screw terminals
Power supply EI transformer (1250 VA), 4 capacitors each 20000 μF
Power consumption 540 W; 280 W without signal; 1 W in standby mode
Dimensions (WxHxD) 440x224x485 mm
Weight 48 kg

Francis Adamiak
Author: Francis Adamiak

Francis Adamiak is a passionate audiophile and expert in high-fidelity audio equipment, with a focus on amplifiers and speakers. Drawing on years of experience and a deep love for sound quality, he shares in-depth reviews and insights on the latest audio technology.