LUXMAN M-7f

Commentary

This is the third generation M-7 series stereo power amplifier equipped with ODNF circuit.

It can be used not only as a normal stereo power amplifier, but also as a high-power monaural power amplifier with a BTL connection.

It is equipped with a ODNF (Only Distortion Negative Feedback) circuit created by reexamining the relationship between music signal and distortion.
In order to realize this circuit, LUXMAN first developed an ultrawide-band, high-slew rate, low-distortion circuit that does not require phase correction for the amplification circuit of the music signal, eliminating the phase correction that cannot be avoided with conventional negative feedback circuits (NFB).
We have also reconsidered the NFB. By detecting only the distortion component from the output and feeding it back to the final stage of the amplifier circuit, only the distortion component is removed from the output waveform. This separates the NFB circuit from the music signal, and achieves a high initial slew rate and ultra-wide bandwidth that rise instantaneously.
In addition, the DC servo amplifier for ultra-low frequency control, which had been the cause of unnatural coloring in the low frequency range in the NFB circuit, has been eliminated to unify the tone color of all bands.

A unique high-inertia power supply is used for the power supply.
This circuit is equipped with a special electrolytic capacitor with excellent instantaneous discharge characteristics to minimize delay control by always keeping sufficient energy in the power supply.
The power transformer is equipped with a 530 VA large-capacity toroidal core power transformer and two 22,000 μ Fx large electrolytic capacitors.

A highly rigid box isolation structure has been adopted to reduce unnecessary vibration and noise.
The M-7f uses an FRP chassis base with excellent vibration absorption mode as the base, and the parts are firmly fixed to the thick chassis to realize a housing structure that avoids vibration noise.
The layout is designed so that the power transformer, electrolytic capacitor, and amplifier block do not directly interfere with each other. Each block is shielded by a shield plate and internal filters are strengthened to prevent interference from flux and noise.

Uses custom-made parts exclusively for Luxman.
The resistor is based on an acoustically excellent carbon film resistor, and has been studied in a wide range of areas including selection of alumina, etching, carbonization, terminal material, terminal shape, and press-fitting method to improve the amount of information transmitted.
We also use custom parts such as power transformers, block capacitors, electrolytic capacitors, copper-styrene capacitors, copper bus bars, and high-purity cables.

Equipped with a large 120x100mm power meter.
This meter uses a logarithmic display system that makes it easy to read movement. In addition, the exterior is made of 10 mm thick acrylic resin, and attention is paid to the color of the light emitted and the illumination effect of the brand logo, making it a high-quality item.
It is equipped with functions to turn on / off meter operation and lighting.

The input terminals are equipped with balanced and unbalanced terminals.
Both models are equipped with independent left and right attenuators with 6-contact fixed resistance switching system. In addition, a reference position W output at 1 V input for ease of use when combined with other models.

The speaker terminal uses an independently developed large terminal that can be used with banana terminals.

Equipped with a line phase sensor that senses the polarity of the AC power supply, setting can be done with the correct polarity.

There was a glossy wooden cabinet sold separately.

Model Rating

Type	Stereo power amplifier
Continuous effective output	When using stereo : When using monaural : 300W + 300W (4 Ω) 200W + 200W (8 Ω) 600W (8 Ω)
Input sensitivity	1V/200W (8 Ω)
Input impedance	Coaxial : 33k Ω Balance : 66k Ω
Total harmonic distortion factor	0.004% or Less (1 kHz, 8 Ω) 0.08% or Less (20 Hz ~ 20 kHz, 8 Ω)
Frequency characteristic	20 Hz ~ 20 kHz + 0 -0.1 dB 10 Hz ~ 100 kHz + 0 -1.0 dB
Signal-to-noise ratio	118 dB (1 kHz, IFF-A)
Input terminal	Coaxial(RCA) L/R Balance L/R
Output terminal	Speaker terminal for banana plug
Attachment	Large power meter Power meter ON/OFF switch Standby indicator Muting indicator Attenuator / input selector switch BTL switch Remote terminal Remote switch Line phase sensor
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	428W (Electrical Appliance and Material Control Law)
Maximum external dimensions	Width 467x Height 212x Depth 440 mm
Weight	28.0kg
Sold Separately	Wood Cabinet OP-M7W (¥ 38,000)