Technics SU-3150
¥ 44,800 (around 1974)
Commentary
A pre-main amplifier developed based on the same design concept as the SU-3500 and 3200 series.
The main amplifier uses an all-stage direct-coupled OCL circuit that guarantees stable output and damping factor, and the output-stage uses a complete complimentary service configuration to reduce harmonic distortion and intermodulation distortion.
The first stage differential amplifier circuit uses a carefully selected pair transistor with the same characteristics. In addition, a zener diode is used for constant voltage to improve circuit stability.
The Zener diode for circuit stabilization and the Zener diode inserted into the power supply of the differential amplifier suppress the shock sound generated when the power supply is turned on / off.
The equalizer circuit consists of two stages directly connected. High voltage and low noise PNP transistor is used for the first stage and high voltage and low noise NPN transistor is used for the second stage.
In addition, a wide range of cartridges can be used by ensuring a large dynamic range by raising the power supply voltage with two power supplies (plus and minus).
The tone control circuit uses the NF circuit of the main amplifier section to control the tone by attenuating the feedback amount from the speaker output terminal to the first stage operation amplifier by frequency.
Since this method operates the signal within the circuit loop of the main amplifier, there is little increase in distortion due to the insertion of the tone control circuit, and smooth tone adjustment is possible.
The internal layout is designed with the switch part close to the rear panel to reduce the effect on sound quality caused by the wiring which transmits weak signals.
Equipped with low / high filter.
Equipped with two tape monitoring functions, it is possible to record program sources to two devices simultaneously by switching the knob, or to dub from one deck to another.
Equipped with two speaker outputs.
Equipped with two phono terminals.
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Model Rating
| Type | Pre-main amplifier | ||
| Circuit system | Fully complimentary service all-stage direct-coupled differential-amplification OCL circuit | ||
| Main Amplifier Section | |||
| Music power | 80W (4 Ω) 60W (8 Ω) |
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| Effective power |
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| Output Bandwidth (8 ω) | 10 hz to 40 khz -3dB | ||
| Harmonic distortion factor | 0.5% | ||
| Residual noise | 0.5mV | ||
| Damping factor | 30 (8 Ω) | ||
| Applicable load | Main or Remote : 4 Ω ~ 16 Ω Main + Remote : 8 Ω ~ 16 Ω |
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| Preamplifier Section | |||
| Input Sensitivity / Impedance | Phono1, 2 : 2mV/50k Ω Tuner, Aux : 180mV/40k Ω |
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| Phono maximum allowable input | 120 mv (1 kHz, RMS) | ||
| Harmonic distortion factor | 0.5% | ||
| Signal-to-noise ratio (IHF) | Phono:74dB Tuner, Aux : 82 dB |
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| Frequency characteristic | Phono : RIAA standard curve ± 0.5 dB Aux : 7 Hz to 90 kHz + 0 -3dB |
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| Tape monitor (Tape1, 2) | Playback : 180mV/40k Ω Rec out : 180mV/1k Ω |
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| Tone control | Bass : ± 11 dB (50 Hz) Treble : ± 10 dB (10 kHz) |
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| Loudness | +7dB(100Hz) | ||
| Low filter | 40 Hz, -6dB/oct. | ||
| High filter | 8 kHz, -6dB/oct. | ||
| <General> | |||
| Pwer | 100 VAC, 50Hz/60Hz | ||
| Power consumption | 50W | ||
| External dimensions | Width 386x Height 115x Depth 303 mm | ||
| Weight | 6.1kg | ||
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