Accuphase P-260
¥ 200,000 (released in April 1979)
Commentary
This is a stereo power amplifier that uses a MOS FET as a power amplifier and has improved performance and sound quality by combining accuphase technology.
It is designed to operate with pure A-class amplifier by switching.
In the class A operation system, the operation area of the push-pull element always completely overlaps.
The operation is switched by a pure electronic switch (PAT, PEND) instead of switching the circuit bias resistance with a switch.
The output stage consists of a parallel push-pull MOS FET.
Since the MOS FET does not generate notching distortion during high-frequency transmission, the high-frequency characteristics are improved, and the harmful TIM distortion is also improved.
All amplification stages are composed of an original symmetrical push-pull of Acuphase.
It has excellent element characteristics, especially linearity, can realize extremely low distortion rate with a small amount of NFB, and is composed of an amplifier circuit with high stability. As a result, sound quality is improved by reducing IM and TIM.
In addition, the capacitor is removed from the NFB loop in order to remove the coloration. The output DC drift caused by this is stabilized by the use of dual elements in the input differential circuit to provide a stable layout against temperature changes.
High-efficiency and low-leakage flux type CI core is used for the power supply.
This CI core is similar to that used in pole-mounted transformers for household power supplies, where load fluctuation is severe. The winding is divided into two balanced windings, and efficiency and fluctuation rate are improved.
Two filter capacitors of 40000 μ F have been designed for low impedance audio applications.
It is a logarithmic compression type peak level meter, and the output at 8 Ω load can be directly read along with the dB scale.
In addition, peak hold is possible by the manufacturer function changeover switch. The hold time is approximately 3 seconds, and the peak generated during that time is held, so that peak monitoring of the program source is possible.
In class A operation, the operation switch automatically switches the rated output 30W to 0 dB.
An attenuator is provided to adjust the input level so that the gain of the amplifier can be controlled by the total efficiency including the speaker.
It can be changed in steps from -20dB to 1 dB independently on the left and right.
It is equipped with a sensor that automatically controls the bias when the cabin air temperature reaches 70 ° C and prevents overheating in order to cope with heat generation due to class A operation and to maintain long-term durability.
In normal operation, the voltage supplied to the output FET is controlled to prevent overheating as well.
Natural rosewood finish cabinet is sold separately.
Model Rating
Type | Stereo power amplifier | ||||
Continuous average power (new IHF, both channel operation 20 Hz to 20 kHz, Distortion Rate 0.01% or Less) |
Normal Operation 4 Ω : 180W/ch 8 Ω : 130W/ch 16 Ω : 65W/ch Class-A Operation 4 Ω : 45W/ch 8 Ω : 30W/ch 16 Ω : 15W/ch |
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Harmonic distortion factor (both channel operation Output 0.25W ~ Rated Output, 20 Hz ~ 20 kHz) |
4 Ω : 0.01% or less 8 Ω : 0.005% or less 16 Ω : 0.005% or less |
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IM distortion factor (new IHF) | Not more than 0.003% | ||||
Frequency characteristic | Rated output : 20 Hz ~ 20000 hz + 0 -0.2 dB New IHF : 0.4 Hz to 120000 Hz + 0 -3.0 dB |
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Damping factor (new IHF) | 80 (20 Hz to 20000 Hz) 120(50Hz) |
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Input Sensitivity / Input Impedance | Rated output : 1.3V/50k Ω New IHF, 1W output : 0.12V/50k Ω |
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S/N (A-corrected) | 120 dB (Rated Input, Input Short) 100 dB (at new IHF, 1W output) |
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Output meter | Logarithmic compression type -40dB to + 6 dB and output direct reading With Peak Hold Switch |
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Semiconductor used | 33 tr, 16 fet, 4 ic, 40 di, 2 optocouplers | ||||
Pwer | 100 V, 117 V, 220 V, 240V/50, 60 Hz | ||||
Power consumption |
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External dimensions | Width 445x Height 160 (Including Legs) x Depth 390 mm | ||||
Weight | 19.7kg | ||||
Sold Separately | Wood Cabinet A-8 (¥ 15,000) |