Technics SE-A7
¥ 80,000 (released in October 1981)
Commentary
1U stereo / mono DC power amplifier equipped with new class A system and linear feedback circuit.
In addition to a synchronous bias circuit that eliminates switching distortion and crossover distortion, it is equipped with a linear feedback circuit that realizes theoretical distortion = 0 and output impedance = 0.
Monaural driving is possible by switching the switch on the rear panel.
The tap of the high power transformer is switched according to the load impedance, and the rated output is 60W + 60W at 4 Ω load in the same manner as at 8 Ω load. This greatly reduces the amount of heat generated and reduces the radiator capacity to 70% of conventional capacity.
Two ultra-thin transformers are used. The two transformers are arranged to cancel electromagnetic radiation to each other and prevent external induction.
By adopting a high-efficiency radiator using a heat pipe, the heat generated by the output transistor is dispersed laterally.
The power meter uses an FL display tube of 12-segment logarithmic compression display.
The meter range is a 2-step switching system of x1 and x0. 01.
It is equipped with a pure electronic protection circuit using a relay to protect the amplifier circuit against short circuit of the speaker terminal and to protect the speaker against abnormal operation of the amplifier.
In addition, it is equipped with a heat detection and protection circuit. When the internal temperature of the amplifier rises abnormally, the gain is automatically lowered and stable operation is achieved.
Model Rating
Type | Stereo / mono DC power amplifier |
Effective output (20 Hz to 20 kHz) | Stereo : 60W + 60W (8 Ω, 0.003%) Mono : 120W (8 ohm, 0.007%) |
Total harmonic distortion factor (20 Hz to 20 kHz, 8 Ω) |
Stereo : 0.003% (at rated output) 0.0015% (at rated output -3dB) Mono : 0.007% (at rated output) |
TIM | Unmeasurable |
Frequency characteristic | 20 Hz ~ 20 kHz + 0 -0.1 dB 0.7 Hz ~ 200 kHz + 0 -3dB |
Signal-to-noise ratio (IHF-A) | 115dB |
Residual noise | 0.2mV |
Damping factor | 100 (8 Ω) |
Output meter reading range | 0.001W ~ 1W 0.1W ~ 100W |
Input Sensitivity / Impedance | 1V/47k Ω |
Load impedance | Main or remote (stereo) : 4 Ω ~ 16 Ω Main and remote (stereo) : 8 Ω ~ 16 Ω Main and remote (mono) : 8 Ω ~ 16 Ω |
Pwer | 100 VAC, 50Hz/60Hz |
Power consumption | 145W |
External dimensions | Width 430x Height 53x Depth 365 mm |
Weight | 9.5kg |