M-700u, a power amplifier, is a new mid-range model that inherits our powerful drive circuit including the latest version, ODNF 4.0 circuit whose distortion characteristics and S/N performance have been significantly improved and also including 4-parallel push-pull structure with 3-stage Darlington to pursue Luxman's development philosophy for power amplifiers, "satisfying both high drivability and sound quality of high density". The output from 120 W/8Ω to up to 840 W/1Ω instantaneously exploits the full potential of speaker characteristics. M-700u is a new-generation stereo power amplifier that combines richly expressive sound and high power without losing the music dynamism.
A powerful drive circuit is necessary to amplify sound signals from a control amplifier with high fidelity and to exploit the performance of various speakers. M-700u has achieved the output of up to 840 W + 840 W (1Ω) instantaneously from the rated output of 120 W + 120 W (8Ω) and 210 W + 210 W (4Ω). Moreover, the BLT mode allows the user to use the unit as a monaural amplifier with the rated output of 420 W(8Ω). A 4-parallel push-pull structure with 3-stage Darlington is used in this circuit to acquire such high power. The latest version, ODNF 4.0 circuit, that has achieved primary slew rate speed indicating the startup performance by feeding back only distortion components, ultra-wide bandwidth, and low level of distortion is adopted for the amplifier circuit. Precise reproduction of a small sound signal has enhanced the elaborate sound expression. Setting up to 6 W with which sound range can be practically and sufficiently acquired to the Class A operation range, it has made its high power consistent with sound expression of high density.
* ODNF is an abbreviation for "Only Distortion Negative Feedback".
M-700u is equipped with high-performance EI type power transformer whose rated capacity is as much as 550 VA with a reputation for its tone quality full of dynamism including bass range perseverance to support overwhelmingly powerful power supply unit.
In order to transmit the powerful drive force generated by the large-scale output circuit without any loss, super-thick wires for major current systems and large-capacity speaker relays with low resistance in which 4 contacts are connected in parallel are equipped. Transmission of thoroughly low impedance has been achieved, and 350 of the damping factor has been accomplished.
The combination of block capacitor with high-capacity of 80,000μF (10,000μF x 8) whose right and left channels are independent and a power transformer configures high-inertia power supply that offers both instantaneous force and a sense of stability.
The beeline construction is adopted, which makes the internal configuration of the power amplifier reasonable and also makes the wiring route shortest. The traditional wiring pattern of the substrate with use of copper foil of approx. 100μm in thickness allows highly pure signal transmission to be achieved.
A large-scale needle-type meter is adopted to provide not only audible but also physical sensation for the lively feeling of the music. This meter can be switched in 3 steps with use of the switch on the front panel as follows: Operation ON/Light ON → Operation ON/Light OFF → Operation OFF/Light OFF.
A loopless chassis structure is used for the cabinet to eliminate increased ground impedance and the effect of generated magnetic field. Gradation cast-iron insulator legs are attached to prevent resonance thanks to its characteristics of that the metallic structure becomes smaller from the center to the periphery of the leg.
M-700u consists of original custom parts, considering the sound quality as the first priority, such as resistances, capacitors, even all wires, which have contributed to realizerich tone that Luxman has pursued.
|Output||120W + 120W (8Ω)/at stereo
210W + 210W (4Ω)/at stereo
420W (8Ω)/at monaural
|Instantaneous max. output||840W + 840W (1Ω)/at stereo
1,680W (2Ω)/at monaural
|Input sensitivity||1.1V/120W (8Ω)
|Input impedance||Unbalanced 51kΩ
|Frequency response||20Hz to 20kHz (+0, –0.1dB)
1Hz to 130kHz (+0, –3.0 dB)
|Total harmonic distortion rate||0.009% or less (1kHz/8Ω)
0.1% or less (20Hz to 20kHz/8Ω)
|S/N ratio (IHF-A)||115dB|
|Amplification circuit||ODNF 4.0|
|Output||Bipolar 4-parallel push-pull|
|Power transformer||EI type 550VA|
110W (under no signal)
0.4W (at standby)
|External dimensions||440(W) x 190(H) x 427(D) mm
front side knob of 2mm and rear side
terminal of 38 mm included in depth
|Accessories||Dedicated remote cable
|Speaker terminal Supported Y-lug terminal dimension||Width of part a: 14mm or less
Width of part b: 7mm or more
* Connection may not be performed
depending on the shape of the