Audio Database

AU - α 607 mr

MR series pre-main amplifier with New Hyper α -X balanced circuit.

New Hyper α -X balanced circuit is adopted in order to reduce the generation of electrical noise generated inside the circuit to 0 for operation.
This circuit is composed of a Hyper α -X balanced circuit and an advanced Wilson current mirror type vertically symmetrical balanced constant current circuit developed by further developing the Wilson current mirror high CMRR type constant current circuit which realizes a theoretical improvement effect of 140 dB in CMRR.
As a result, we have succeeded in making the driver stage into a closed loop with separate windings, adjusting the current dispersion due to DC offset caused by the asymmetry of elements in the circuit, and improving the stability of the operation of the circuit itself.
In addition, the main power supply section of the output stage, in which transformers and electrolytic capacitors are concentrated, is also a closed loop with separate windings. Through the entire system from the sound inlet to the sound outlet, an optimum operating environment for a balanced amplifier is constructed.
In addition, it uses the NM-LAPT dedicated audio device.

In order to improve response to instantaneous signals, a new diamond differential circuit is adopted in the drive stage. Since - output can be taken out without phase inversion, current supply capability for input signals that change rapidly is high and excellent characteristics are realized.
In addition to the cascade connection of the first stage FET, the driver power supply section is vertically symmetric and balanced, making the circuit wide range and high speed, and making the operating characteristics of the New α -X balanced amplifier more excellent.
It is also effective in preventing sound quality degradation when connecting to external devices with different impedances.

New α -X balanced power supply is used for the power supply part.
The output stage is a balanced closed type and the driver stage is a vertically symmetric balanced constant current power supply. The closed loop configuration is completely independent from the earth. This prevents the adverse effect of unbalanced power supply current, which causes the deterioration of sound quality, on sound quality.
In addition, we have achieved stable high current supply capability by carefully selecting original parts such as large power transformers with special structures, electrolytic capacitors for power supplies, and fast recovery diodes.

Vibration from power supply system and vibration system is controlled by reinforced twin monaural construction and opposed mechanical feedback.

High-quality parts such as resistors and capacitors with gold-plated leads and insulators with a special structure that disperses and absorbs vibrations from the outside are used.

By connecting to the power amplifier / direct input terminal, each source can pass through the circuit at the shortest distance, and it can be directly connected to the power amplifier.
It is also equipped with a source power direct function.

A 6-row detent volume is used.

Model Rating
Type Integrated amplifier
Power Amplifier Unit
Effective output (10 Hz to 20 kHz
Simultaneous operation of both channels)
105W + 105W (6 Ω)
90W + 90W (8 Ω)
Total harmonic distortion factor (at effective output) 0.003% or Less (8 Ω)
Cross modulation distortion factor 0.003% or Less (8 Ω)
Damping factor 150 (8 Ω)
Frequency Response (1W) DC ~ 300 khz + 0 -3dB
Input Sensitivity / Impedance (1 kHz) 1V/5k Ω
Signal-to-noise ratio (A network) 120 dB or more
Dynamic Power 280W (2 Ω)
220W (4 Ω)
155W (6 Ω)
TIM Sawtooth Measurement limit value or less
Slew rate 180 V / μ sec
Rise time 0.6 μ sec
Preamplifier Section
Input Sensitivity / Impedance (1 kHz) Phono MM : 2.5mV/47k Ω
Phono MC : 300 μ V/100 Ω
CD, Tuner, Line, Tape/DAT1, 2 : 150mV/20k Ω
Phono maximum allowable input MM:210mV(THD 0.01%)
MC:21mV(THD 0.1%)
Frequency Response (1W) Phono MM : 20 Hz to 20 kHz ± 0.2 dB
CD, Tuner, Line, Tape/DAT1, 2 : DC ~ 200 khz + 0 -3dB
Signal-to-noise ratio (A network) Phono MM : 88 dB or more
Phono MC : 70 dB or more
CD, Tuner, Line, Tape/DAT1, 2 : 110 dB or more
Tone control Maximum variation of Bass : ± 6 dB (50 Hz)
Maximum variation of Treble : ± 6 dB (15 kHz)
Subsonic filter 16 Hz (-3dB), 6dB/oct.
Loudness + 6 dB (50 Hz), + 4 dB (10 kHz)
Rated power consumption 250W
External dimensions Width 430x Height 162x Depth 452 mm
Weight 18.0kg
Sold Separately Real Side Wood SW-AU4 (1 set, ¥ 14,000)