Audio Database


Exclusive M5a
500,000yen(one set, the 1988 release)

Unreturned Class-A monophonic power amplifier.

At M5a, the full-time staff has finished the component partses for which a special order was given to the special purpose which reaches about 90 percent of an overall by an one-set one-set handmade.
The circuit tester of careful quality control one-set one-set exclusive duty of an in-use cage and all the products does a listening comprehension test, and also aging which reaches also in 72 hours (for three days) by an actual music signal is performed.
Furthermore, two sets of the products chosen from the finished product for every lot at random are sent to the development staff's origin, thorough audition, analyzation, and study are added, and the quality is recorded on the history card called a severe checking and chart.

It returned to the origin of the amplifier of "amplifying an input signal faithfully and reproducing as an output signal", and the new super linear circuit where the property which was excellent without applying NFB is acquired is developed and introduced.
Thereby, the dynamic distortion of TIM distortion etc. was lost fundamentally, and the stability in a wide area is secured.

Switching distortion and crossover distortion serve as Class-A operation amplifier which is not generated theoretically.
In order to supply high power with allowance despite a Class-A operation, an exclusive power source is prepared in Class-A biases, and play sound is pulled out efficiently.
Moreover, since the power-source efficiency ratio is raised, there is no exothermic of a transient made into the difficulty of Class-A amplifier, and the necessity for a cooling fan has been lost.

The mass toroidal transformer in which low leakage flux and the stable regulation are obtained is adopted as a power transformer.
While having adopted the oxygen-free-high-conductivity-copper line of a polyesters coat with the twice [ usual ] as many cross section as this as a coil and improving a regulation much more, the coil temperature rise is also suppressed to one half.
Furthermore, the fast workshop of S/N is attained by adopting a toroidal scheme effective for a falloff of leakage flux.
Moreover, in the transformer case, distortion and a noise are suppressed using the resin which are the body not conducting current and non-magnetic material as a style of double Mie, such as being filled up with the silicon carbide powder which furthermore, is a radio-wave absorber.

In order for - quantity region to riot and to prevent a resonance while measuring the improvement in a RF property, and originating in the structure of a film capacitor, the film capacitor for pure audios is adopted.
The material of the film has prevented the resonance by the polycarbonate with small dielectric loss and the degree of insulation using the compound structure of the polypropylene which was highly excellent in the RF property, winding this up firmly with a low speed and a high tension, losing wrinkles and stress, and making full use of a still more nearly special volume core and a heat-shrink resin.
Moreover, in order to prevent the influence of an external electric field, the double shielding is given with the electric conduction resin case and the electric conduction resin tube.

4 core power cord for audios which added and developed the study from the origin of the power cord is equipped.
By using high oxygen free high conductivity copper of a conductometric for a conductor, the loss in the wire rod was reduced and the nonlinear extensive distorted modification is achieved.
Moreover the cross interferencee of two power transformers was suppressed, and the improvement in source impedance is also finished, and a polyethylene with a low dielectric constant is adopted as an insulator, and a loss is reduced. The conductor oscillation is prevented.

The glass epoxy group board is adopted as the printed circuit board.
By adopting oxygen free high conductivity copper of 99.99% of a purity as a conductor, opening in old 35micro moreover, and using it as 280micro thick copper, while achieving a nonlinear extensive modification, conductor resistance is stopped to one eighth and stable signal transmission without a loss is made possible.
Moreover, since this substrate is excellent in the wetproof property, it suppressed the transition of the electrostatic capacity in a Copper foil to the relative minimum, has brought about the preventing of the leakage in a circuitry, and has improved the crosstalk during an input/output, S/N, and every distorted property.

Aluminum excellent in nonmagnetic was used for the structure material of a chassis, and a magnetic distortion which becomes the origin of a noise is eliminated.
Moreover, adoption of the radiation fin of a vibration distributed, floating mounting of the transformer through a rubber damper, etc. have adopted the thorough vibration proof structure.

The fuse for audios which performed the examination study is adopted as a material so that a fuse may not have an ill effect on a tone quality.
The mouthpiece quality of the material was changed into the pure copper from the conventional brass, and while suppressing conductor resistance to about 1/3, the nonlinearity is improved sharply.
Moreover, it changed to nickel plating which is the magnetic substance, the tin plating which is non-magnetic material was adopted, and a magnetic distortion is banished.

An exclusive propagation circuit is prepared not only in an imbalanced input but in the hot and cold side, and the balance input which negates a noise component in inputting the signal of negative phase, respectively is also carried.

The large-sized speaker terminal of the vice sticking-by-pressure type which plated with gold at the contact surface is carried so that the speaker cable of a very thick can connect comfortably.

Input Output
Audio Power
Glass Die
The Polar

Rating of a mode
Form Class-A unreturned monophonic power amplifier
Effective output 300W (8 ohm, 20Hz - 20kHz)
Input sensitivity Unbalance: 1.5V
Balance: 1.5V
Input impedance Unbalance: 50kohm
Balance: 600ohm
Power window Peak level meter
Power consumption (Electrical Appliance and Material Control Law) 400W
Dimensions Width 438x height 203x depth of 417mm
Weight 26.3kg