Luxman C-900u ultimate

Planet Audio
Planet Audio
Planet Audio
Planet Audio

Luxman top model, new for 2015. The C-900u is a fully balanced design. Three single-ended, plus one dedicated external processor {Home Theater Bypass} and three balanced inputs. Two single-ended and two balanced outputs. A fully balanced design with tone controls is extremely difficult to implement but the Luxman engineers have achieved this to allow music lovers to enjoy all of their music collection. Luxman’s latest compact version of the LECUA 1000-WM volume control (LUXMAN Electric Controlled Ultimate Attenuator with Weighting Matrix Technology).  as well as the electronic input selector.  Luxman’s most advanced ODNF circuit is employed, release 4.0. delivers state-of-the art musical performance.

 

■ Simple circuit configuration

 

LECUA 1000WM unifies the amplifier,  volume control functions and power supply in a three dimensional module, resulting in a circuit that is electrically very simple. Long-term reliability is excellent, with performance and sound quality that will remain unchanged also after prolonged use.

 

■ LECUA 1000WM uses analog processing

The LECUA 1000WM circuit converts the music signal from a voltage into a current, switches gain by means of switching on the attentuaes, and then reconverts the current into a voltage. The entire process is carried out in the analog domain.

 

■ Same ergonomic feel as a conventional high-quality volume control

 

The counter balanced volume control knob position is detected by a dedicated CPU which in turn selects the current switches for LECUA 1000WM operation. Operating the knob therefore feels exactly the same as with a conventional control, and operation via the remote control is also possible.

 

■ Mute and Balance control are also implemented by LECUA 1000WM

The functions of the attenuator and the left/right balance control are covered by the LECUA 1000WM circuit as well, eliminating the need for additional circuit stages. Keeping the configuration simple helps to maintain high performance and sonic purity.

 

LECUA 1000WM is a radically different volume control principle that eliminates all variable resistors from the signal path and provides top-notch performance and sound quality. Because the music signal is not affected by changes in impedance, high signal-to-noise ratio and low distortion are maintained at any volume control setting.

 

■LECUA 1000WM ensures high S/N ratio and uniform frequency response

Unlike conventional volume controls, LECUA 1000WM does not introduce a change in impedance at any volume setting. Consequently, there is no deterioration of S/N ratio and frequency response remains totally uniform. The benefits are especially apparent at settings that correspond to normal listening levels, because the sound remains perfectly transparent and the tonal quality is not altered in any way.

 

■ No more left/right tracking differences or crosstalk

 

Because LECUA 1000WM is an electronic circuit employing fixed-value resistors, there is virtually no left/right tracking error also at low volume levels. Since channels can be kept separate, crosstalk also does not present a problem

 

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Volume Control 

The integrated amplifiers also benefit from the C1000f in that they use a variation of the LECUA 1000 volume control. At any single volume setting only a few resistors are in circuit per channel. The less devices in the signal path, the purer the sound, the cleaner the music.

At low listening levels, potentiometers have trouble keeping both channels in balance,  so one channel might easily be 3dB louder than the other. With the volume control made of discrete parts, this is no longer an issue.

 

ODNF
 
Luxman holds many patents for audio engineering, amongst them is the application of Global Negative Feedback to the output stage, which while widely used throughout the audio industry, they no longer use themselves. 

Luxman nowadays use a distortion reduction circuit called Only Distortion Negative Feedback (ODNF). This system works by isolating noise & distortion at the output from the music signal and sparingly applying negative feedback to suppress them. Conventional negative feedback systems can have an adverse effect on the music, introducing phase distortion. “The circuit features such an ultra-wide range, ultra- high slew rate and ultra low distortion that it does not use phase compensation for the music signal amplifying circuits.” This new technology also ensures that need for a DC servo circuit is alleviated, again improving sound quality.

 

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Tone Controls 

The tone controls might seem like an anachronism in this day and age of minimalism, but they can be remarkably effective in bring to life a less than perfect music collection. We all have music gems in our collection that are sonicly challenging. A lot of the 1980’s CDs are quite harsh sounding and the digital glare can be quite fatiguing. Reduce the treble slightly and while the harsh CD is not going to suddenly sound like a reference recording, at least it will now be perfectly listenable. Sit back relax, enjoy the music & forgot about the HiFi. When you want to bypass the tone controls, just engage the Line Straight switch, either from the remote control or from the front panel.

 

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Simplicity allows for ease of use, while still maintaining fully control of this extremely flexible control amplifier.

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At a touch of the button (Zoom) on the remote control; you can increase the display size.

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Luxman have designed their own EI transformers for over fifty years.

 

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Gold Plated, Peel Coat Circuit Boards

Printed Circuit Boards normally have a green coat (dye) that can be printed upon, so the manufacturer knows where to place the copper traces and where to insert the resistors & capacitors. LUXMAN’s designers don’t like the sound of the green dye, in their extensive research they found that it smears the sound, so instead they print onto a plastic peel coat and remove it once the traces and mounting holes are in place. Then the copper traces are gold plated to reduce resistance across the circuit, as well as eliminate copper’s corrosion over time..

In the photo above you will notice that Peel Coat circuit boards are an off-white color, and that the traces are gold plated. It’s this fanatical attention to detail that delivers such superior sound quality.

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A feature new to Luxman’s preamp is the “Pre In” or a Home Theater Bypass for connection to an external Processor.

Inputs Unbalanced 3 system, balanced 3 system
Outputs Unbalanced 2 system, balanced 2 system
Input Sensitivity/Impedance unbalanced 255mV / 43kΩ, balanced 255mV / 86kΩ
Output Voltage / Impedance unbalanced rated 1v/90Ω Maximum 11V
balance rated 1V/180V Maximum 22.5v
Harmonic Distortion 0.009% (20Hz – 20kHz), balanced 0.005% (20Hz-20kHz)
Frequency Response 20Hz – 20kHz (+0, -0.1dB), 5Hz – 120kHz (+0, -3.0dB)
Signal-to-noise ratio Unbalanced 123dB, balanced 126dB
Power Consumption 42W, 2.2 (at standby)
Dimensions (W x H x D) 440 x 130 x 430mm
Weight 20 kg