Technics SE-A5MK2
¥ 150,000 (released in 1983)
Commentary
This is a stereo power amplifier developed with Technics's original technology as a power amplifier for the digital audio age.
The output stage is a 3-stage Darlington configuration using high-voltage transistors of Pc150W connected by two pins, and a total of 1.2 kW Pc has been obtained. The power supply circuit uses a large transformer of 390 VA and a large capacitor of 80 V / 8200 μ Fx4, and is designed independently on the left and right sides to eliminate interference between channels.
It is equipped with a power linear circuit unique to Technics.
This is a development of linear feedback circuit technology. This effect is brought to the output stage of the amplifier, and linearity is dramatically improved, and distortion caused by low impedance load of the speaker at every moment is suppressed.
It is equipped with a unique computer drive circuit and by introducing a computer to the bias control of the signal system, the output transistor, which repeats rapid temperature changes in response to changes in the music signal, is always driven at the optimum idle current (ICQ), eliminating transient crossover distortion.
Equipped with a linear feedback circuit (LFB), which is an independent feedback circuit in the NFB loop that enables infinite amplification. It realizes theoretical distortion = 0. It achieves an excellent distortion reduction effect of almost infinite at the lower limit of the range of audibility and more than 40 dB at the upper limit of 20 kHz.
It is equipped with a synchronous bias circuit, and by supplying a constant bias in synchronization with the idle cycle of the output transistor, the output stage is always in the active state to eliminate switching distortion. Moreover, by making the signal system and bias current circuit independent, crossover distortion is minimized, and clear sound quality of class A operation is achieved with high efficiency.
It uses a concentrated power block, and the output stage and power supply part are integrated with an ingenious structure, eliminating the adverse effects of electromagnetic fields that cause high frequency distortion.
Equipped with a purely electronic protection circuit controlled by a computer.
It is equipped with a large power meter that can directly read from 0.0001W micro output to 300W without range switching.
Model Rating
Type | Stereo DC power amplifier |
Effective power | 150W + 150W (8 ω, 20 Hz-20 kHz, 0.002%) |
Total harmonic distortion factor | 0.002% (20 Hz to 20 kHz at Rated Output) |
TIM | Unmeasurable |
Output bandwidth | 5 Hz ~ 100 kHz (THD 0.01%) |
Frequency characteristic | DC ~ 20 khz + 0 -0.1 db DC ~ 200 khz + 0 -3dB |
Signal-to-noise ratio (IHF-A) | 123dB |
Residual noise | 0.11mV |
Damping factor | 100 (8 Ω) |
Load impedance | Main or remote : 4 Ω ~ 16 Ω Main + remote : 8 Ω ~ 16 Ω |
Input Sensitivity / Impedance | 1V/47k Ω |
Output meter reading range | -60dB to + 5 dB 0.0001W ~ 1 kW (8 Ω) |
Meter indication accuracy | ± 3 dB (less than -50dB, 20 Hz to 20 kHz) ± 2 dB (-50dB or more, 20 Hz to 20 kHz) |
Pwer | 100 VAC, 50Hz/60Hz |
Power consumption | 300W |
External dimensions | Width 430x Height 178x Depth 416 mm |
Weight | 18.4kg |