Aurex SB-620
¥ 85,000 (around 1976)
Commentary
A pre-main amplifier that achieves both power and quality.
A pure complimentary service OCL circuit directly connected to all stages is used for the power amplifier.
By applying a high voltage of ± 55 v to the equalizer amplifier section, a high input resistance of 400 mv is achieved. The RIAA element uses a high-precision metal film resistor and a plastic film capacitor to achieve an accuracy within ± 0.2 db of deviation.
The circuit is a 3-stage direct-coupled circuit with one stage differential.
The tone amplifier section is an NF type with simple change characteristics, and consists of a two stage direct-coupled circuit including one stage differential.
This circuit is also composed of ± 2 power supply.
The power supply section uses a large cut core transformer with low flux and stable regulation and a 10,000 μ Fx2 large-capacity electrolytic capacitor. The power supply transformer is designed as a separate pre-winding wire. The pre-section is driven by a constant voltage ± 2 power supply over all stages.
It has a duplicate switch that can copy between two decks.
Tape 2 terminals are also provided on the front panel.
It is equipped with a muting circuit when the power is turned on and an automatic recovery protection circuit which protects the speaker and transistor by using a relay.
The volume used is an attenuator type volume with less error in linking the left and right channels.
This volume is a 22-point click high precision type.
The tone control has two levels of high and low turnover frequency, and equipped with a defeat position.
Equipped with 3-step switching type muting circuit.
Low filter and high filter can be switched in 2 stages respectively.
Actually measured data sheet is included.
This data sheet includes seven items : input sensitivity (phono, aux), continuous output, harmonic distortion factor, signal-to-noise ratio, Phono maximum allowable input, frequency-distortion factor characteristics, and RIAA deviation.
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Model Rating
| Type | Pre-main amplifier | ||
| Circuit system | Pure complimentary service OCL circuit directly connected to all stages | ||
| Power Amplifier Unit | |||
| Output (both channel drive) |
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| Harmonic distortion factor | 0.2% or Less (Continuous Output) 0.05% or Less (at 1W Output) |
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| Cross modulation distortion factor | 0.2% or Less (Continuous Output) 0.05% or Less (at 1W Output) |
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| Output Bandwidth (IHF) | 6 Hz ~ 60 kHz (8 Ω) | ||
| Damping factor | 30 (8 Ω) | ||
| Residual noise | 0.5 mv (8 Ω) | ||
| Preamplifier Section | |||
| Input Sensitivity / Impedance | Phono1, 2 : 2.0mV/50k Ω Aux, Tuner, Tape : 150mV/50k Ω |
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| Recorded output | Tape rec:150mV DIN:30mV |
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| Equalizer allowable input | MAG:400mV(RMS) | ||
| RIAA deviation | + / - 0.2 dB | ||
| Signal-to-noise ratio (IHF) | Phono:73dB Aux:90dB |
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| Harmonic distortion factor | 0.05% (Continuous Output) | ||
| Frequency characteristic | 10 Hz to 50 kHz -1dB | ||
| Tone control |
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| Muting | -10dB, -20dB | ||
| Filter | Low : 30 Hz, 10 Hz High : 8 kHz, 20 kHz |
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| Loudness | + 9 dB (100 Hz), + 3.5 dB (10 kHz) | ||
| <General> | |||
| Semiconductor used | Transistor : 50 Diode : 25 pcs |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||
| Power consumption | 145W | ||
| External dimensions | Width 450x Height 148x Depth 375 mm | ||
| Weight | 14kg | ||
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