YAMAHA A-5
¥ 45,000 (around 1979)
Commentary
A pre-main amplifier with slim proportions and technologies such as DC power amplifiers.
The circuit configuration consists of an equalizer amplifier with a differential-amplifier circuit using a low-noise transistor, a Yamaha NF-CR tone control amplifier with a low-distortion ICs using an input differential-final stage SEPP, a differential-input using a low-noise dual transistor, and a DC-power amplifier with a pure complimentary service SEPPOCL.
Each unit is analyzed by an HP-IB system combining a spectrum analyzer and a computer with a measurement limit of 0.00005%. All units are ± 2 power supply system, and consist of input differential-output stage complimentary service SEPP.
The equalizer amplifier is the first stage current mirror differential amplifier, the second stage common-emitter amplifier, and the final stage A-class PURE CON SEPP-OCL.
A-5 is also compatible with MC cartridge by switching between MM and MC with Phono SW.
The power amplifier consists of a current mirror differential amplifier using a low-noise dual transistor at the first stage, a grounded emitter amplifier at the pre-drive stage, and a Darlington connected pure SEPP-OCL at the last stage.
The tone control uses Yamaha's original NF-CR type tone control, which has excellent control characteristics and low distortion rate.
The control characteristics are as follows : Bass at 500 Hz turnover and 20 Hz control range ± 10 dB, Treble at 3 kHz turnover and 20 kHz control range ± 10 dB.
The signal to Rec Out can be selected regardless of the program being played by the amplifier.
It is equipped with a subsonic filter that cuts the ultra low range.
15 Hz, 12dB/oct.
It is equipped with a loudness switch.
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Model Rating
| Type | Pre-main amplifier | ||||
| Rated output | 40W + 40W (20 Hz to 20 kHz, 8 Ω, 0.02%) | ||||
| Power bandwidth | 10 Hz to 70 kHz (20W, 8 Ω, 0.05%) | ||||
| Damping factor | 50 or More (1 kHz, 8 Ω) | ||||
| Input Sensitivity / Impedance | Phono MM : 2.5mV/47k Ω (220 pF) Phono MC : 250 μ V/100 Ω Tuner, TV, AUX, Tape : 150mV/47k Ω |
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| Maximum allowable input | Phono MM : 200 mV or more (1 kHz, 0.005%) Phono MC : 20 mV or more (1 kHz, 0.05%) |
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| Output Voltage / Impedance | Rec Out 1, 2 : 150mV/600 Ω (12 v maximum) | ||||
| Frequency characteristic | Phono MM → Rec Out : 20 Hz to 20 kHz, ± 0.2 dB Phono MC → Rec Out : 30 Hz to 20 kHz, ± 0.5 dB Tuner → SP Out : 4 Hz to 100 kHz, + 0 -2dB |
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| Total harmonic distortion rate (20 Hz to 20 kHz) | Phono MM → Rec Out : 0.005% or less (3 V) Phono MC → Rec Out : 0.05% or less (3 V) Tuner → SP Out : 0.007% or less (20W, 8 Ω) Phono → SP Out : 0.01% or less (20W, Volume-30dB) |
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| Total harmonic distortion rate (1 kHz) | Phono MM → Rec Out : 0.003% or less (3 V) Phono MC → Rec Out : 0.005% or less (3 V) |
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| Intermodulation distortion factor (8 Ω, 20W) | AUX → SP Out : 0.005% or less (70 Hz : 7 kHz = 4 : 1) | ||||
| 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 | ||||
| N. D. C. R (0.1% strain) | Phono → SP Out : 10 mW ~ 40W (Volume -20dB, 1 kHz) | ||||
| Tone control characteristics |
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| Subsonic filter | 15 Hz, 12dB/oct. | ||||
| Loudness characteristics (Volume -30dB) | 70Hz:+9dB 1kHz:+2dB 10kHz:+7dB |
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| Channel separation | Tuner → SP Out : 65 dB (1 kHz, 5.1k Ω) | ||||
| Headphone Output / Impedance | 8 Ω load rated output : 50 mW (220 Ω) | ||||
| Service outlet | 2 linked, 1 non-linked | ||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||
| Power consumption | 115W | ||||
| External dimensions | Width 435x Height 112x Depth 338 mm | ||||
| Weight | 7.8kg |