Accuphase P-350
¥ 300,000 (released in July 1994)
Commentary
This is a stereo power amplifier with excellent performance, high purity and natural music playback in a simple design.
The output stage employs a high-power multi-emitter audio power transistor with a collector loss of 100W and a collector current of 10A. This device has excellent characteristics such as frequency characteristics, current amplification linearity and switching.
High output is achieved by connecting this in 4-parallel.
The amplifier circuit employs a current feedback amplifier circuit that feeds back the output signal in the form of a current.
The principle of this circuit is as follows : First, the impedance of the feedback input terminal is lowered to detect the current, and then the current is converted into I-V (current-voltage conversion) by a transimpedance amplifier to produce an output signal. Since the impedance of the feedback input terminal is extremely low, phase rotation is difficult to occur, and there is almost no need for phase guarantee. Therefore, it has excellent dynamic characteristics such as rise and sound quality is improved by natural energy response.
Also, the current feedback amplifier circuit has a feature that its frequency characteristics hardly change depending on the designed gain.
It can be used as a monaural power amplifier by bridge connection.
Bridge connection is a method of inputting signals of the same voltage and opposite phase to each other to 2-channel amplifier, and connecting speakers to the output terminals of both amplifiers. It can be used as a high-power monaural amplifier.
Equipped with balanced connection terminal.
The balanced input of the P-350 is an offensive that sends the signal directly to the non-inverting (+) and inverting (-) inputs of the input circuit.
The copper foil side of the printed board is plated with gold to improve sound quality.
The input terminal is also made into a gold plate.
The power supply section uses a large transformer of approximately 700 VA.
The aluminum electrolytic capacitor is equipped with two large-capacity capacitors of 40,000 μ F/71WV (charge capacity 2.8 coulombs).
The output terminal uses a large speaker terminal for banana plug that is machined from solid brass.
It is equipped with two output systems and supports bi-wiring connection.
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Model Rating
| Type | Stereo power amplifier | ||||
| Continuous Average Output (20 Hz to 20 kHz) |
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| Total harmonic distortion factor | Stereo Specifications : 0.02% (4 Ω ~ 16 Ω Load) Monaural Specification : 0.02% (8 Ω ~ 16 Ω Load) |
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| IM distortion factor | 0.02% | ||||
| Frequency characteristic | 20 Hz ~ 20 kHz + 0 -0.2 dB (Continuous Average Output) 0.5 Hz ~ 160 kHz + 0 -3.0 dB (at 1W Output) |
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| Gain | 28.0 dB (both stereo and monaural specifications) | ||||
| Load impedance | Stereo specification : 4 Ω ~ 16 Ω Monaural specification (bridge connection) : 8 Ω ~ 16 Ω |
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| Damping factor | Stereo specification : 360 Monaural specification (bridge connection) : 180 |
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| Input sensitivity (at 8 Ω load) |
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| Input impedance | Unbalanced input : 20k Ω Balance Input : 40k Ω |
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| S/N (A correction) | 120 dB (Input Short, Continuous Average Output) | ||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||
| Power consumption | 65W (non-input) 300W (Electrical Appliance and Material Control Law) 490W (at 8 Ω load rated output) |
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| Maximum external dimensions | Width 475x Height 170x Depth 435 mm | ||||
| Weight | 23.6kg |