Accuphase P-1000
¥ 1,100,000 (released in June 1999)
Commentary
This is a stereo power amplifier that inherits the design technology of M-2000 and A-50V and uses the highest grade elements to further polish the sound quality.
The output element of the P-1000 uses a high-power transistor with a collector loss of 130W and a collector current of 15A. This element has excellent characteristics such as frequency characteristics, linearity of current amplification factor and switching. Ultra-low impedance is achieved by configuring this element with 11-parallel push-pull.
These elements are mounted on a huge heat sink made of aluminum die-cast for efficient heat radiation processing, and realize a high output power amplifier with linear characteristics up to ultra-low impedance load of 1 Ω.
The circuit configuration employs a current feedback amplifier circuit that feeds back the output signal in the form of current.
In this circuit, the impedance of the input terminal on the feedback side is first lowered to detect a current, which is then converted into I-V (current-voltage) by a transimpedance amplifier to produce an output signal.
Since the impedance of the feedback input part is extremely low, phase rotation hardly occurs, and phase compensation is hardly necessary, various characteristics can be greatly improved with a small amount of NFB. It has excellent dynamic characteristics such as start-up and natural energy response in terms of sound quality.
The P-1000 can be used as a bridge connected monaural power amplifier with a changeover switch mounted on it.
Bridge connection is a method in which the same signal is input to two amplifiers of different polarity, and a speaker is connected to the output terminals of both amplifiers to supply high power.
The power amplifier circuit uses a printed circuit board made of Teflon.
Teflon has low dielectric constant, extremely low leakage current (low loss) between patterns formed on printed circuit boards, excellent heat resistance and high frequency characteristics, and other characteristics.
By using this Teflon base material, the propagation speed of the signal is increased due to the low dielectric constant, and the transmission loss is small, so purer transmission of the signal is possible.
High-purity copper is used for components that allow signals to pass through, such as printed board copper foil, earth plate for ripple current, capacitor terminals, input terminals, and speaker terminals. The P-1000 is plated with gold to improve sound quality.
The power transformer employs a large toroidal transformer with a large power capacity of approximately 1.5 kVA. In addition, it is fixed to the non-resonant aluminum case with a high-efficiency heat radiation structure using a filler with excellent heat conduction and anti-vibration thereby shielding the external influence.
Since a thick copper wire is wound around a doughnut-shaped core, the toroidal transformer has an extremely low impedance and is compact and extremely high in conversion efficiency. In particular, the P-1000 uses a super-ring type. As the cross-section of the iron core is close to a circle and the coil is close to a circle, the adhesion is good, so loss is small and leakage flux and buzzing under load can be reduced. Furthermore, by reducing the cross-section of the iron core and increasing the weight ratio of the copper wire, iron loss and inrush current can be reduced.
The aluminum electrolytic capacitor is equipped with two large capacity 56,000 μ F capacitors.
It is equipped with a very large speaker terminal that can be used with very thick speaker cables.
The terminal is made of pure brass, machined into a gold plate, and covered with a mold cap for insulation.
Equipped with a balanced connection that is resistant to external induction noise.
In balanced transmission, the noise component generated in the cable enters both poles in phase, so when combined, only the noise component disappears and high-quality signal transmission becomes possible.
Equipped with an analog large power meter that can directly read a wide power range by logarithmic compression.
Meter operation and lighting can be turned on/off.
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Model Rating
| Type | Stereo power amplifier | ||||
| Rated continuous average power (20 Hz to 20 kHz) |
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| Total harmonic distortion factor |
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| IM distortion factor | 0.003% | ||||
| Frequency characteristic | 20 Hz ~ 20 kHz + 0 -0.2 dB (at rated continuous average output) 0.5 Hz ~ 150 kHz + 0 -3.0 dB (at 1W Output) |
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| Gain | 28.0 dB (for stereo/mono specifications) | ||||
| Load impedance | Stereo specification : 2 Ω ~ 16 Ω Mono specification : 4 Ω ~ 16 Ω * Only music signal can be loaded with stereo1 Ω and mono2 Ω) |
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| Damping factor | 300 (for stereo/mono specifications) | ||||
| Input sensitivity (8 Ω load) |
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| Input impedance | Balance Input : 40k Ω Unbalanced input : 20k Ω |
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| S/N (A correction, input short) | 114 dB (at rated continuous average output) 117 dB at clipping output |
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| Output meter | Logarithmic Compression Type with Display / Off Function Output reading scale for -60dB to + 3 dB and 2 Ω load |
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| Pwer | 100 VAC, 50Hz/60Hz | ||||
| Power consumption | 148W (no input) 1,070W (Electrical Appliance and Material Control Law) 635W (at 8 Ω load rated output) |
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| Maximum external dimensions | Width 475x Height 258x Depth 545 mm | ||||
| Weight | 50kg |