Pioneer SX-555
¥ 48,500 (around 1975)
Commentary
This is a stereo receiver that achieves both usability and sound quality.
The power amplifier section employs a single-stage differential amplified pure complimentary service OCL circuit using dual transistors with uniform characteristics in ± 2 power supply system.
The equalizer circuit uses a high-voltage low-noise IC with 1 stage differential amplification using ± 2 power supply system.
This circuit limits the RIAA deviation to within ± 0.3 dB.
Low-noise PNP-NPN 2-chip direct connection amplifier is used for the tone control part, and CR type is used for the tone circuit.
The control knob for both bass and treble has an 11-point click stop. This control volume is a newly developed center defeat type. When the control volume is set to the center OFF position, the tone circuit is passed in the same way as the tone defeat, and flat characteristics without waviness are obtained.
A 6,800 μ Fx2 capacitor is used for the power supply.
With a built-in loudness contour, the bass and treble are corrected independently of the tone control knob, and a balanced sound quality can be obtained even in low volume playback.
Equipped with two tape input / output terminals.
Equipped with a microphone mixing circuit.
You can control the volume of the microphone freely by operating the mixing knob.
In order to improve sound quality, the circuit is integrated with a large circuit board and the shielding wire for input is eliminated.
All input / output terminals and circuits except for the speaker circuit are integrated to prevent degradation of the high frequency band due to the influence of the shield wire.
The front-end part of the tuner uses an FET with low noise coefficient and a frequency number line type precision 3-row varicon.
The FM-IF section uses a well-established high-integration IC and two stage ceramic filter.
The 5-stage limiter also eliminates AM noise.
The MPX section uses a PLL system with a high-integration IC.
A highly integrated IC is used for the AM tuner section.
A large flywheel with high inertial efficiency is used for the tuning mechanism.
The height of the panel surface of the SX 555 is equal to that of the cassette deck CT-3, so you can enjoy a unified design.
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Model Rating
| Type | Stereo receiver |
| Amplifier Unit | |
| Circuit system | Pure complimentary service OCL |
| Effective output (20 Hz to 20 kHz, both channels driven) | 20W + 20W (4 Ω) 20W + 20W (8 Ω) |
| Harmonic distortion factor (20 Hz to 20 kHz) | 0.3% (Effective Output) 0.07% (8 Ω at 10W output) 0.07% (8 Ω at 1W output) |
| Intermodulation distortion factor (50 hz : 7 khz = 4 : 1) | 0.3% (Effective Output) 0.07% (8 Ω at 10W output) 0.07% (8 Ω at 1W output) |
| Output Bandwidth (IHF, both channel drives) | 5 Hz ~ 50 kHz (Distortion Factor 0.3%) |
| Output terminal | Speaker : A/B (4 ~ 16 Ω), A + B (8 ~ 16 Ω) Headset : 4-16 Ω |
| Damping factor | 25 (20 Hz ~ 20 kHz, 8 Ω) |
| Input Sensitivity / Impedance | Phono : 2.5mV/50k Ω Mic : 5.5mV/50k Ω Tuner, Aux, Tape play1/2/2 (DIN) : 150mV/50k Ω |
| Phono maximum allowable input (harmonic distortion rate 0.1%) | 200mV(1kHz) |
| Output Level / Impedance | Tape rec1/2:150mV Tape rec2 (DIN) : 30mV/80k Ω |
| Frequency characteristic | Phono (RIAA deviation) : 30 Hz to 15 kHz ± 0.3 dB Tuner, Aux, Tape play : 10 hz to 60 khz + 0 -1dB |
| Tone control | Bass : ± 9 dB (100 Hz) Treble:+11dB -7dB(10kHz) |
| Loudness contour (Volume-40dB) | + 7 dB (100 Hz), + 3 dB (10 kHz) |
| S/N ratio (IHF, A-Network, short circuit) | Phono:70dB Tuner, Aux, Tape play : 90 dB |
| FM Tuner Section | |
| Practical sensitivity | S/N 50dB Mono : 4.5 μ V Stereo : 50 μ V IHF Mono : 2.0 μ V |
| S/N | mono:72dB stereo:67dB |
| Harmonic distortion factor | mono:0.15%(100Hz) 0.15%(1kHz) 0.3%(10kHz) stereo:0.3%(100Hz) 0.3%(1kHz) 0.8%(10kHz) |
| Capture ratio | 1.0dB |
| Effective selectivity | 60dB(400kHz) |
| Frequency characteristic | 50 Hz to 10 kHz + 0. 2-0. 5 dB 20 Hz to 15 kHz + 0.2 -2.0 dB |
| Separation | 35dB(1kHz) 30 dB (50 Hz to 10 kHz) |
| Image interference ratio | 60dB |
| IF interference ratio | 90dB |
| Spurious interference ratio | 75dB |
| AM suppression ratio | 50dB |
| Carrier leak suppression ratio | 40dB |
| Stereo switching level (muting operation level) | 3.0 μ V |
| Antenna | 300 Ω Balanced Type 75 Ω Unbalanced Type |
| <AM Tuner Section> | |
| Practical sensitivity | 300 μ V/m (bar antenna) 15 μ V (IHF) |
| Selectivity | 35dB |
| Signal-to-noise ratio | 50dB |
| Image interference ratio | 40dB |
| IF interference ratio | 65dB |
| <General> | |
| Semiconductor used | FET : 1 IC : 5 Transistor : 27 Diode, etc. : 22 pcs |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| AC outlet | Power switch interlock : 1 system Power switch not linked : 1 system |
| Power consumption (Electrical Appliance and Material Control Law) | 75W |
| External dimensions | Width 430x Height 139x Depth 307 mm |
| Weight | 8.5kg |
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