Marantz PM-80BL
¥ 60,000 (around 1989)
Commentary
Pre-main amplifier with class A / class AB switching system.
The power supply section uses a 18,000 μ Fx2 special specification electrolytic capacitor in addition to a large power transformer to supply a stable current even at high output.
The speaker circuit uses an extremely thick OFC wire to ensure smooth power supply to the power transistors.
It has a powerful noise killer circuit.
Rectification noise that occurs when alternating current is converted into direct current. Since even a small amount of high-frequency noise in the range from 100 kHz to 1 MHz adversely affects sound quality, a noise-killer circuit is used to cut out this high-frequency noise.
In addition, noise is completely eliminated by the circuit configuration such as separating the rectifying circuit from the signal system.
The power transistor is a parallel push-pull configuration using a Pc-100W power transistor with excellent linearity, and the gain is increased by three stage Darlington connection.
The heat sink has an independent structure on the left and right sides to reduce mutual interference in the output circuit, thereby reducing crosstalk.
The phono equalizer uses a low-noise FET, which is combined with an audio IC to create a low-noise amplifier to maintain the purity of the low level phono signal.
By rolling off frequencies below 30 Hz, modulation due to low frequencies is prevented.
The parts are made of carefully selected materials.
Especially for the signal system, we have adopted an electrolytic capacitor that uses fibrous protein fibrin of silk and mixed paper of Manila hemp as separators.
The printed circuit the printed circuit board is made of paper polyester substrate with excellent damping properties, which reduces turbidity and realizes sound quality with high transparency.
A class A / class AB change-over switch is provided to enjoy class A sound quality.
It is possible to switch between class A normally and class AB when high power is required.
The effect on sound quality is minimized by means of a circuit configuration in which the voltage switching circuit is laid out near the power stage, and by minimizing the distance of the bias switching using a photo coupler.
The source direct switch jumps all switches and control circuits such as tape monitors and processors, and allows direct input to the power amplifier through the dedicated volume.
Input terminals are installed in the Line 5, and tape input / output terminals are installed in the Route 3.
It also has a built-in processor connector that can be connected to a graphic equalizer, etc.
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Model Rating
| Type | Stereo pre-main amplifier | ||||
| Rated Output (20 Hz to 20 kHz, Both Channels Driven Simultaneously) |
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| Dynamic Power |
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| Total harmonic distortion factor (1 kHz, 8 Ω load) | 0.0008% | ||||
| Intermodulation Distortion Factor (SMPTE) | 0.008% | ||||
| Output bandwidth (8 ohm load, 0.03%) | 10 Hz to 50 kHz | ||||
| Frequency characteristic | CD Source Direct : 10 Hz ~ 100 kHz + 0 -3dB | ||||
| Damping factor | 180 (8 Ω load, 20 Hz to 10 kHz) | ||||
| Input Sensitivity / Impedance | Phono MC : 250 μ V/100 Ω Phono MM : 2.5mV/47k Ω High Level : 150mV/33k Ω |
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| Phono maximum allowable input (1 kHz) | MC:16mV MM:160mV |
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| RIAA deviation (20 Hz to 20 kHz) | + / - 0.2 dB | ||||
| Signal-to-noise ratio (A network) | Phono MC:75dB Phono MM:85dB High Level:105dB |
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| Tone control | Bass : 100 Hz, ± 6 dB Treble : 10 kHz, ± 6 dB |
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| Pwer | 100 VAC, 50/60Hz | ||||
| Power consumption | 220W (Electrical Appliance and Material Control Law) | ||||
| External dimensions | Width 454x Height 165x Depth 380 mm | ||||
| Weight | 17.5kg |