SANSUI AU-555A
¥ 41,800 (around 1970)
Commentary
The PB series pre-main amplifier has been upgraded from the AU 555, and the contents and design have been renewed.
All stages are composed of silicon transistors.
Uses the SEPP, ITL and OTL systems of pure complimentary service and Darlington circuits that use silicon transistors as power transistors.
In order to avoid adverse effects of electrolytic capacitors on music signals, we use as many direct coupled circuits as possible, reduce the number of capacitors, increase the circuit impedance where necessary, and use Mylar capacitors.
Where electrolysis is absolutely necessary, a Mylar capacitor is connected in parallel to improve high-frequency characteristics.
Bass, Midrange, and Treble Triple Tone Control.
In addition, since it is a click step type control, more accurate compensation of program and room acoustic can be performed.
The preamp section uses specially selected low-noise silicon transistors to reduce the noise.
The entire amplifier circuit from the first stage to the final output stage is composed of NF amplifier, and frequency characteristics, distortion and S/N are improved.
The preamp section and main amplifier section can be separated.
The main amplifier and preamp power supplies are equipped with independent ripple filter circuits.
This completely shuts off the hum components and stabilizes the power supply.
Equipped with two speaker outputs.
It is equipped with functions such as NF type low filter, high filter, loudness control, tape monitor circuit for simultaneous monitoring during recording, headphone terminal, etc.
Model Rating
| Type | Stereo / pre-main amplifier | ||||
| Main Amplifier Section | |||||
| Rated output |
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| Total harmonic distortion factor | 0.5% or Less (Rated Output) | ||||
| Intermodulation Distortion Factor (SMPTE, 60 Hz : 7000 Hz = 4 : 1) | 0.5% or Less (Rated Output) | ||||
| Power Band With (IHF) | 20 Hz ~ 40000 Hz (8 Ω) | ||||
| Frequency characteristic | 20 Hz to 40000 Hz, ± 1 db | ||||
| Channel separation | 60 dB or More (1 kHz, Rated Output) | ||||
| Hum and noise (IHF) | 100 dB or more | ||||
| Input Sensitivity / Impedance | 1 V (Rated Output) / 100k Ω or More | ||||
| Load impedance | 4 Ω ~ 16 Ω | ||||
| Damping factor | 50 (8 Ω Load) | ||||
| Preamplifier Section | |||||
| Output voltage | Maximum power : 5 v Rated output : 1 V |
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| Total harmonic distortion factor | 0.1 or Less (Rated Output Voltage) | ||||
| Frequency characteristic | 20 Hz to 30000 Hz, ± 1 db | ||||
| Channel separation (1 kHz, rated output) | Phono1 and 2 : 45 dB or more Tuner, AUX : 50 dB or higher |
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| Hum and noise (IHF) | Phono1, 2 : 70 dB or more Tuner, AUX : 80 dB or higher |
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| Input Sensitivity / Impedance (1 kHz, Rated Output Voltage) | Phono1, 2 : 2mV/50k Ω Tuner : 180mV/50k Ω AUX : 180mV/50k Ω Tape Play (Pin) : 180mV/50k Ω Tape Recorder (Din) : 180mV/50k Ω |
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| Recording Output (1 kHz, Input Voltage) | Tape Rec(Pin):180mV Tape Recorder(Din):30mV |
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| Equalizer | Phono : RIAA NF Type | ||||
| Controls | Bass : 30 Hz, ± 12 dB Midrange : 1.5 kHz, ± 5 dB Treble : 15 kHz, ± 10 dB Loudness : + 3 db (10 khz), + 8 db (50 hz) |
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| SWITCH | Low filter : 50 hz, -8dB High filter : 10 kHz, -7dB |
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| <General> | |||||
| Pwer | 100 V, 50Hz/60Hz | ||||
| Power consumption | 130W | ||||
| External dimensions | Width 395x Height 127x Depth 278 mm | ||||
| Weight | 8kg | ||||