The C-700u control amplifier is our new middle range model that inherits some of our magnificent innovations, seen in our high end model, the C-900u, including our latest ODNF version 4.0 circuit, with significantly improved distortion characteristics and signal to noise performance and our new LECUA 1000, a computerized attenuator directly connected to the amplifier circuit, which enables smooth volume changes without any deterioration of sound quality. This unit is also multifunctional, the loudness function interacting with the volume and tone controls, external pre-input connectivity and a fluorescent display with zoom and dimmer controls.
The C-700u features the new LECUA 1000 high precision electronically controlled attenuator in an unbalanced configuration. An accurate volume adjustment mechanism is fundamental to the operation of a control amplifier. The LECUA* system is extremely resistant to external vibration and changes in sound quality over the volume control range, as well as being extremely durable. The LECUA circuit uses stepped fixed resistance and increasing the number of steps from 72 to 88 allows more delicate volume control adjustments from 0dB to 87dB with no deterioration of sound quality. This circuit also accurately handles any left and right balance adjustments. Our latest negative feedback circuit, ODNF** version 4.0, achieves even higher performance by being quadruple paralleled in the first main amplifier stage, triple paralleled in the first error detection stage and featuring a Darlington connected second stage. Only the distorted components of the audio signal are fed back to the amplification circuit to optimize the negative feedback effect. Increased primary slew rate and ultra-wide bandwidth contribute to an extremely low level of distortion, especially in the high frequency range. An improved signal to noise ratio allows the full expression of delicate musical pieces. *LECUA stands for "LUXMAN Electrically Controlled Ultimate Attenuator".** ODNF stands for "Only Distortion Negative Feedback".
In order to embody the philosophy of "Power Amplifier Driver", meaning a component which powerfully drives a power amplifier connected in the next stage, the C-700u has a large capacity power supply featuring an OI-type power transformer and is regulated by two 3,300μF blocking capacitors. This circuit creates a firm power base to support the sound quality of the C-700u.
The highly visible fluorescent display is equipped with a dimmer and has a four level zoom mode, adjusted via the remote control. The two part display usually displays the input source and volume level and is also eye-friendly and clearly visible from the listening position.
The C-700u is equipped with unbalanced external pre-amp input terminals to which an external pre-amplifier in your AV system may be connected. The balanced inputs have the option of phase switching which can be adjusteded and memorized for each balanced input.
The new LECUA 1000 system uses a 3D component layout to both minimize the signal route and improve it's efficiency. The ultimate solution for a high class control amplifier is realized by the direct connection between the attenuator circuit and the amplification circuit, eliminating the concept of independent, individual circuit blocks.
A loopless chassis structure has been used for the enclosure to eliminate increased ground impedance and the effects generated by electrical or magnetic fields. Cast-iron isolator legs prevent resonance thanks to the characteristics of their metallic structure, the density gradient decreases from the center to the periphery of each leg. The legs eliminate adverse effects caused by vibration and effects from the power transformer or the supporting surface.
|Input sensitivity/Input impedance||Unbalanced 250mV/46kΩ
|Output/Input impedance||Unbalanced rating 1V/90Ω, max. 11V
Balanced rating 1V/600Ω, max. 11.5V
|Frequency response||20Hz to 20kHz (+0, -0.1dB)
5Hz to 120kHz (+0, -3.0dB)
|Total harmonic distortion||Unbalanced 0.007% (20Hz to 20kHz)
Balanced 0.010% (20Hz to 20kHz)
|S/N ratio (IHF-A)||Unbalanced 125dB
|Negative feedback circuit||ODNF 4.0|
|Max. tone control range||BASS: ±8dB at 100Hz
TREBLE: ±8dB at 10kHz
|Remote control functions||・Operation・Dimmer・ Input selector
・Output mode・Balanced phase selection
・Record output・External pre-input
・Line straight・Loudness・Volume up/down
2.0W (in standby mode)
|External dimensions||440(W) x 130(H) x 430(D) mm
(including 17mm front panel knob and 14 mm rear panel speaker terminals)
|Net weight||14.6 kg|