SANSUI BA-5000
¥ 390,000 (released in 1975)
Commentary
A stereo power amplifier developed as a highly reliable high-power amplifier by introducing the latest circuit technology and new materials everywhere.
The power amplifier consists of two differential stages with active load and two drive stages. 8 power transistors per channel are used for the output-stage quad parallel push-pull, pure complimentary service system.
In addition, the buffer amplifier in the preceding stage is composed of three elements using differential amplification for the input circuit. Phase inversion in mono operation is combined with relay, and high power of 600W is realized in mono operation.
The power supply uses a toroidal transformer with a capacity of 1 kVA with good regulation and low leakage flux. The left and right wires are independently wound to prevent influence between channels and obtain good regulation.
In addition, with the exception of the output stage, a stabilized power supply is supplied to the buffer amplifier and the drive stage to provide more margin.
Equipped with auto trans-type output transformer.
By adopting an output transformer, the back electromotive force of the voice coil of the speaker is prevented from affecting the NF loop of the amplifier by the band pass effect of the transformer, and stability and sound quality are improved.
In addition, the transformer damping effect protects the speaker and provides maximum output regardless of the impedance of the speaker.
It employs a forced air-cooling system that automatically operates a cooling fan based on temperature detection by a heat sinker, and releases heat from a power transistor.
In addition to the ASO detection type current limiter circuit and overload protection fuse, a safety design is adopted in preparation for accidents. At the same time, the newly developed two color light emitting diode changes from green to red in the event of an error by the power indicator.
The front panel has a double structure consisting of a panel for fixing the RCA rack and an aluminum decorative panel.
The set can also be used vertically with large handles on the front panel and back for easy carrying.
It is equipped with a large peak indication power meter with RMS display.
The upper side has an output display scale and the lower side has a dB scale. The output can be read directly in W.
Model Rating
| Type | Stereo power amplifier | ||||
| Effective power |
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| Load impedance | Stereo : 2 Ω, 4 Ω, 8 Ω Mono : 4 Ω, 8 Ω, 16 Ω |
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| Power Band With (IHF) | 20 Hz ~ 30 kHz (8 Ω) | ||||
| Total harmonic distortion factor | 0.1% or Less (at Rated Output) 0.08% or Less (at 1/2 Rated Output) |
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| Cross modulation distortion factor | 0.1% or less (70 Hz : 7 kHz = 4 : 1, SMPTE) | ||||
| Frequency Response (at 1W) | 15 Hz ~ 30 kHz + 0 -2dB | ||||
| Damping factor | 10 (8 Ω) | ||||
| Channel separation | 60 dB or More (1 kHz) | ||||
| Hum and noise (IHF) | 100 dB or more | ||||
| Input Sensitivity / Impedance | 700mV/50k Ω | ||||
| Power consumption | 490W (rated) 1350W maximum |
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| External dimensions | Width 482x Height 222x Depth 466 mm | ||||
| Weight | 49kg |