LUXMAN M-12

Commentary

Stereo power amplifier with thin design.

Parallel push-pull connection is used for the output stage.
Since the parallel push-pull method can set the current per transistor to be small, excellent wide-area characteristics can be obtained, and linearity against current can be improved. In addition, Pc can be taken large. The M-12 uses carefully selected transistors with particularly fast switching speed in the output stage, and implements circuit devices such as AB class operation to eliminate notch distortion in the high-frequency range.

DC amplifier configuration is adopted.
In the conventional circuit method, a large amount of NFB is applied in order to eliminate harmonic distortion. However, due to the influence of the large-capacity capacitor included in the NFB loop, a time lag occurs, and not only can the cancellation effect be obtained as desired, but the time lag causes transient distortion.
Taking this point into consideration, we made a DC amplifier configuration in which a large capacitor is removed from the NFB loop.

DML-IC is used for the power amplifier circuit.
In addition to the emitter-follower circuit with constant-current drive to improve the high-frequency load condition of the pre-drive stage, the emitter-follower circuit with constant-current drive is provided to insulate the pre-drive stage for A-class operation from the influence of the pure complimentary service stage for A-class operation.

The power supply consists of two large power transformers and two electrolytic capacitors with improved sound quality (10,000 μ Fx2) for the positive and negative power supplies. In addition, the constant-voltage power supply for the pre-drive stage is separated from the left and right, making it a completely independent power supply for the left and right channels.
This eliminates interference between the left and right channels in the power supply.

All parts such as resistors, semi-fixed resistors, capacitors, etc. are carefully selected.

Model Rating

Type	Stereo power amplifier
Effective power	80W + 80W (8 Ω, both channel operation, 20 Hz to 20 kHz)
Total harmonic distortion factor	0.006% or Less (8 Ω, 80W, 20 Hz to 20 kHz)
Cross modulation distortion factor	0.006% or Less (8 Ω, 80W, 60 hz : 7 khz = 4 : 1)
Output bandwidth	5 Hz to 100 kHz -3dB (8 Ω, 0.1%)
Frequency characteristic	DC ~ 100 kHz -1dB or less
Input sensitivity	600mV
Input impedance	20k Ω
SN ratio (IHF-A correction, input short)	110 dB or more
Separation	80 dB or More (20 Hz to 20 kHz)
Damping factor	150 or More (8 Ω, 1 kHz)
Protection circuit	Speaker protection circuit with DC drift detection Overcurrent protection circuit
Attachment	Input capacitor IN-OUT switching Left and right independent attenuator
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	200W (Electrical Appliance and Material Control Law)
External dimensions	Width 436x Height 95x Depth 328 mm
Weight	14.5kg