Specifications of LUXMAN M-7 Luxman

LUXMAN M-7
¥ 350,000 (released in January 1996)

Commentary

A stereo power amplifier developed by inheriting the development concept of the B-10.

The CSSC (Complimentaly Single Stagger Circuit) circuit is adopted to reproduce the sound rise more vividly.
All stages of the CSSC circuit are directly connected to each other. The first stage consists of a dual-FET complimentary service and a cascode-connected transistor complimentary service circuit. The second stage uses a common-base type current transmission circuit. The cut-off frequency is sufficiently high and the amplifier bandwidth can be secured only by the phase rotation of the first stage. As a result, natural signal amplification that does not require sufficient phase correction is achieved.
The current amplification stage is a three stage Darlington complimentary service circuit with high amplification factor, and the last stage is a push-pull configuration using six single channels of a large multi-emitter bipolar transistor (Pc150W) to ensure excellent drive capability.

A unique OD β (Optimized Dual NFB) circuit is used to match the tone of all bands.
In general NFB, DC and AC feedback are separately used. In this case, AC affects the sound quality in the middle and high range and DC affects the sound quality in the low range. However, in order to control the low range, a servo amplifier is inserted only in the DC range to give a large amount of NFB. This creates a sense of inconsistency in the sound quality between the middle and low range.
In the OD β circuit adopted in the M-7, DC stability is ensured while eliminating the DC servo amplifier by refining the bare characteristics of the circuit to a high degree, and a natural sense of unity of tone is obtained.

A unique high-inertia power supply is used for the power supply.
The M-7 uses a toroidal power transformer with enhanced regulation, and uses a large-capacity block capacitor to improve its bare characteristics, such as increasing its instantaneous power supply capability. By changing the small voltage fluctuations generated by music signals into loose fluctuations, the M-7 realizes a natural power supply in the sense of hearing.

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

High rigidity construction is adopted to reduce unnecessary vibration and noise.
The M-7 uses a large-mass FRP chassis base of 5-point grounding type with excellent vibration absorption mode. Moreover, the weight balance is maintained by the symmetrical structure. In addition to the consideration to prevent temperature difference inside the casing, the M-7 also takes measures including the material, arrangement and shape, such as setting a unique shape to suppress the noise of the heat sink.
As a countermeasure against noise, we have adopted a box isolation structure. In order to eliminate mutual interference between each circuit, each circuit is isolated by a shield plate. Furthermore, each stage is segmented rationally to cut off high-frequency noise and flux.

The power supply units such as transformers, rectifier diodes, and block capacitors are separated from the signal path by an independent power supply room system with a partition structure, reducing the influence of various interference noise and unnecessary vibration.
In addition, the constant voltage circuit is laid out on the amplifier side to eliminate the influence of control time delay and interference noise.

An L/R-independent attenuator with a 6-contact independent fixed resistance switching system is used as the level control mechanism. By using the attenuator type, there is no stray current inside the printed resistor, which is seen in slide-type resistors, thus reducing sound quality degradation.
This attenuator has six selectable positions : - ∞, 30 dB, -20dB, -12dB, -6dB and 0.

It is equipped with two input terminals, a balance terminal and an RCA terminal. The output terminal is equipped with an originally developed banana terminal and an original speaker terminal for Y-lag, as well as a Speakon terminal used in acoustic fields.

We use custom parts such as non-magnetic resistors, electrolytic capacitors, and copper-styrene capacitors that are also used in the B-10.
In addition, copper bus bars are used to reduce impedance fluctuations.

It is equipped with's own line phase sensor, it can unify the polarity of the system.

It is equipped with a remote control terminal. When a control amplifier with remote control output is connected, the power ON / OFF can be linked.

The power cable is a custom-made dedicated cable.
An AC inlet type is used for the power connector.

The power meter uses a large 120x100mm power display meter.
This meter is equipped with an illumination that projects the brand logo three dimensionally.

Aluminum panel and wooden cabinet with unique surface processing are adopted.

There was an upgrade service to M-7i (improved model).