Technics EAA-2010/SU-2010/SU-50A/Technics 50A
¥ 95,000 (released in June 1969)
¥ 95,000 (around 1970)
Commentary
This solid state pre-main amplifier was created by integrating the development technologies of the Technics 10A, 20A, 30A, and 40A tube type amplifiers.
The model number has been changed 3 times : EAA-2010, SU-2010 and SU-50A.
The main amplifier section uses a two stage differential amplifier circuit and an OCL circuit with a two power supply system. All stages are directly connected. The circuit configuration without an output capacitor improves low-frequency characteristics and improves stability and linearity.
The equalizer stage of the preamplifier amp section is composed of 3-stage direct connection NF type using low-noise PNP transistor, which solves the shortage of dynamic range and obtains high S/N.
The tone control circuit is based on Technics's original method using special double volume.
This system has a special structure that combines a silver conductor and a resistor. At the midpoint, both brushes touch the silver conductor, so that all capacitors are removed from the circuit to become a resistance-only circuit, resulting in a flat characteristic.
A protection circuit using four transistors and two diodes is mounted.
This circuit is equipped with an automatic control and protection device that detects the operating point of the power transistor to maintain safe operation, an automatic correction circuit for temperature changes, and an instantaneous recovery type so that even if an excessive current flows, the signal only clips and operation is not interrupted.
The front panel features push-button input selection buttons and a large volume knob to improve usability.
In addition, it uses a design in which the letters on the front panel come out when the switch is turned on.
The pre-out terminal is equipped with two systems, a Low terminal with a rated output of 1 v and a High terminal with a rated output of 5 v.
It is equipped with 4 AC outlets.
Equipped with two types of speaker connection terminals.
Model Rating
Type | Solid state pre-main amplifier | ||||
Circuit system | Full-stage direct-coupled differential amplifier SEPPP OTL-OCL Circuit |
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Power Amplifier Unit | |||||
Music Power (IHF) | 120W (4 Ω) 80W (8 Ω) 50W (16 Ω) |
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Rated Output (IHF) | 40W/40W (4 Ω) 30W/30W (8 Ω) 20W/20W (16 Ω) |
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Frequency response (at rated output) | 5 Hz to 150 kHz | ||||
Signal-to-noise ratio | 95 dB or more (IHF, A-network, input short) | ||||
Input Sensitivity / Impedance | 1V/50k Ω | ||||
Damping factor | 150 (8 Ω) | ||||
Adaptive load impedance | 4 Ω ~ 16 Ω | ||||
Transistor protection circuit | ASO detection method instantaneous return type | ||||
Preamplifier Section | |||||
Input Sensitivity / Impedance (1 kHz, Volume max) |
Phono1, 2 : 1mV/47k Ω Tuner : 100mV/70k Ω Aux1, 2 : 100mV/70k Ω |
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Maximum allowable input (1 kHz, 0.1% distortion rate) |
Phono1, 2 : 140 mV Tuner:10V Aux1, 2 : 10 v |
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Output Voltage / Impedance |
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Tape monitor | Rec out : 100mV/200 Ω Playback : 100mV/70k Ω
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Signal-to-noise ratio (IHF, A-network Input short) |
Phono1, 2 : 70 dB or more Tuner : 90 dB or higher Aux1, 2 : 90 dB or more |
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Total harmonic distortion factor | Not more than 0.1% | ||||
Frequency characteristic |
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Tone control | Bass : + 15 dB ~ -15dB Turnover frequency : 250 Hz, 500 Hz Treble : + 15 dB to -15dB Turnover frequency : 2.5 kHz, 5 kHz |
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Filter | Low : 30 Hz, -12dB/oct. High frequency : 8 kHz, -12dB/oct. |
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Muting | -20dB | ||||
<General> | |||||
Semiconductor used |
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Pwer | 100 VAC / 117 V / 220 V / 240 V, 50/60Hz | ||||
AC outlet | Switched : Route 3 Unswitched : 1 line |
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Power consumption | Rated output : 175 VA No signal : 37 VA |
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External dimensions | Width 420x Height 147x Depth 325 mm | ||||
Weight | 13.5kg |