YAMAHA A-5D
¥ 49,800 (around 1981)
Commentary
A pre-main amplifier based on A-5 and improved.
The equalizer amplifier uses a low-noise FET differential input + high-precision operational amplifier IC.
In addition, the RIAA device uses a metal film resistor with an error margin of ± 1% and a PS capacitor with an error margin of ± 2% to obtain excellent characteristics.
It is also compatible with MC cartridges by switching the Phono switch on the front.
The power amplifier section has a DC configuration using a highly reliable hybrid IC for the voltage amplifier stage and a discrete 3-stage Darlington connection SEPP-OCL for the power amplifier stage.
The power supply uses a 10,000 μ F audio Chemi-Con and a high-capacity transformer, enabling extremely stable operation.
Special attention has also been paid to the preamp section, which deals with minute signals, by using a stabilized power supply, or by transmitting a constant voltage through a separate winding for the lamp.
The protection circuit includes a speaker protection relay that automatically detects DC voltage that is harmful to the speakers, and a PC limiter circuit.
The tone control circuit uses Yamaha's original NF-CR type. Moreover, the newly developed volume makes it possible to obtain simple characteristics.
This tone control circuit has a built-in subsonic filter that protects the speaker by sharply cutting out harmful ultra-low frequencies, such as those caused by sleigh records.
The loudness circuit is equipped with a continuous loudness that can be controlled based on the actual listener's ear.
It is equipped with a high filter to cut off Tap ウヒス and scratch noise.
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Model Rating
| Type | Pre-main amplifier | ||||
| Rated Output (0.01% Distortion) | 20 Hz to 20 kHz : 60W + 60W (8 Ω) 1 kHz : 65W + 65W (8 Ω) |
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| Power bandwidth | 10 Hz to 50 kHz (30W, 8 Ω, 0.05% strain) | ||||
| Damping factor | 80 (1 kHz, 8 Ω) | ||||
| Input Sensitivity / Impedance | Phono MM : 2.5mV/47k Ω Phono MC : 160 μ V/100 Ω Tuner, AUX, and Tape : 150 mv |
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| Maximum Allowable Input (0.01%) | Phono MM:150mV Phono MC:8.0mV |
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| Output Voltage / Impedance | Rec Out : 150mV/470 Ω Headphone (0.01%) : 0.9V/8 Ω, 7V/100 Ω |
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| Frequency characteristic | AUX, Tape, Tuner : 20 hz to 20 khz -0.2 db | ||||
| RIAA deviation (30 Hz to 15 kHz) | Phono MM : + / - 0.3 dB Phono MC : + / - 0.5 dB |
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| Total harmonic distortion rate (20 Hz to 20 kHz) | MC → rec out (3 V) : 0.01% MM → rec out (3 V) : 0.005% AUX, Tape, Tuner → sp out (8 Ω, 1W) : 0.01% |
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| Residual Noise (IHF-A) | 210 μ V or less | ||||
| Signal-to-noise ratio (IHF-A network) | Phono MM:86dB Phono MC:70dB Tuner, TV, AUX, Tape : 104 dB |
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| Residual Noise (Volume Min, IFF-A) | 120 μ V or less | ||||
| Channel separation (Volume -30dB) | MM (short) : 80 dB MC (short) : 80 dB Tuner (5.1k Ω) : 80 dB |
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| SN ratio (IHF-A network, input short) | Phono MM:86dB Phono MC (equivalent to 250 μ V) : 70 dB AUX, Tape, Tuner : 100 dB |
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| Tone control characteristics |
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| Filter characteristics | Low Filter (Built-in) : 10 Hz, 12dB/oct. High Filter : 10 kHz, 12dB/oct. |
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| Continuous loudness control | Maximum correction amount (1 kHz) : -20dB | ||||
| Semiconductor used | Transistor : 19 IC : 3 FET : 4 pcs Diode : 16 pcs |
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| AC outlet | Switched : 2 systems, 90W Unswitched : 1 line, 200W |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||
| Rated power consumption | 150W | ||||
| External dimensions | Width 435x Height 112x Depth 299.5 mm | ||||
| Weight | 7kg |