Technics SE-M100

Commentary

Digital straight amplifier using D. D. D. (Digital Direct Drive) system.

In the digital direct drive system, the output voltage of the DAC is raised to the required volume voltage, and is directly connected to a power amplifier with an amplification factor of 1 (0 dB) without any connection to the amplifier of the analog source. As a result, the output voltage of the DAC is equal to the voltage at the terminals of the speakers. This realizes playback taking advantage of the high S/N ratio of the digital source.
As an output voltage variable means for volume control, a high-voltage I/V converter is provided in the DAC output section to vary the output voltage by changing the exchange ratio.

An amplifier with a voltage amplification factor of 1 (0 dB) basically achieves excellent transmission characteristics including low noise level because it does not amplify the voltage. However, if the normal power amplifier that drives the speakers is simply set to amplification factor 1 with NFB, the operation becomes unstable. In order to develop this problem, a 0 dB power amplifier is realized by installing a classAA and a floating power source, which are high-quality sound technologies unique to Technics.
If you set the volume to minimum, you can maximize the speaker's power with a very low noise level of -140dB at 100W.

The D/A converter is equipped with a newly developed 4 dac linear 20-bit system. In this system, four D/A converters are installed for the positive and negative signals of Lch and Rch respectively. After each component is converted individually, only the parts with good linearity are combined to eliminate 0 cross distortion in principle. In addition, the high-resolution 20-bit high-resolution operation is always achieved regardless of the input signal level, combined with the high-precision 20-bit 8-times oversampling digital filter, and the reproducibility of minute signals is greatly improved.

The power amplifier section has a twin monaural configuration in which the left and right sides are separated, and is arranged separately in the left and right sides.
In addition, the T-type configuration with the preamp section and digital section tightly shielded minimizes L/R interference caused by electromagnetic waves from the large current of the power amplifier section.

The power supply section uses a large power transformer that is completely independent on the right and left sides.
Class 1 OFC wire is used for this transformer to achieve excellent regulation, and 1.6 mm thick rigid chassis and 5 mm thick insulator rubber at the bottom of the transformer to minimize magnetic radiation and mechanical vibration.
We have also adopted a high-speed EX electrolytic capacitor for the electrolytic capacitor of the power supply. By applying biotechnology, the purity of the electrolytic solution has been improved by more than two orders of magnitude, and the slight distortion caused by impurities attached to the electrode is eliminated. In addition, the A1 electrode foil has undergone various improvements such as low-magnification etching, uniform thickness, new film formation method, and electrodeposition coating on the surface.

The D. D. D. volume is adjusted by changing the conversion rate of the I/V conversion circuit. Therefore, the current flowing through the volume is larger than that of the general volume. Therefore, if the conventional volume is used as it is, the distortion becomes large.
The SE-M100 uses a newly developed low-distortion element to improve the distortion by more than 10 times.

High-purity OCC wire is carefully selected for internal wiring, power transformer winding, and lead wire of each part.

It is equipped with two optical digital inputs and one coaxial input / input / output terminal.

The analog input of the SE-M100 is equivalent to that of the pre-main amplifier.

Model Rating

Type	Digital straight amplifier
Effective power	100W + 100W (6 ω, 20 Hz-20 kHz, 0.007%) 90W + 90W (8 ω, 20 Hz-20 kHz, 0.005%)
Total harmonic distortion factor	0.003% (20 Hz to 20 kHz, Rated Output -3dB, 8 Ω)
Frequency characteristic	2 Hz to 20 kHz 0.3 dB
Signal-to-noise ratio	112dB(EIAJ) 83 dB (analog output)
Input Sensitivity / Impedance	150mV/33k Ω (Analog Input)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	235W
External dimensions	Width 430x Height 158x Depth 403 mm
Weight	15.5kg