Stereo Power Amplifier
The advent of digital recordings (PCM) and compact discs (CD) reveals a growing trend toward digitization of audio equipment, and reproduction of high-fidelity sound that differs from conventional analogue recordings is now expected.
Parallel to this trend. the reproduction capabilities of conventional analogue discs with a history of more than a century have shown a significant amelioration resulting from the improvement of cartridges, record players, amplifiers, and other equipment.
The P-300L adopts the state-of-the-art technologies and the Accuphase circuit design philosophy of Push-Pull Circuitry in every stage.
Higher-grade power amplifiers must be endowed not only with superior basic characteristics such as frequency characteristics, low distortion ratio, higher signal-to-noise ratio, but with the capability and power to drive speakers correctly with ample energy so that they can respond accurately to instantly changing, wide-ranging signal variations. This necessitates a power supply with an ample reserve margin to provide the full energy that is required by a powerful output circuit driven by a large current capacity driver stage.
As a result of emphasis on the improvement of sound quality. the P-300L incorporates a power supply comprising a large-sized toroidal transformer and two capacitors each of which with a capacitance of 47,000 uF. Moreover, the P-300L is provided with a powerful output stage with a low impedance. This output stage consists of five parallel push-pull circuits each comprising 2 output transistors.
The maximum power dissipation of each of the 10 transistors is 100 watts. The P-300L can be thus driven at a low impedance providing an outstanding output. For example. the output is 170 watts per channel when connected to an 8 ohm load and 300 watts per channel when connected to a 2 ohm load.
The P-300L can therefore supply a stable energy to such speakers whose impedance greatly fluctuates and thereby can substantially improve the linearity of audio signals. Now, the dynamism of music can be perfectly reproduced.
Each of the driver stages supplying signals to the output stage constitutes a cascode push-pull circuit realizing a sufficiently wide band and low harmonic distortion within the loop. The high quality and stable drive that the P-300L features is thus realized.
The P-300L is provided with 600-ohm Balanced type Input Connectors that exactly matches the 600-ohm balanced type output lines of Accuphase Stereo Pre-amplifiers C-280 and C-200L. Degradation of sound quality due to noises picked up by the signal cables between the preamplifier and the power amplifier is therefore eliminated.
Moreover, since the P-300L incorporates a bridging connection, the output can be increased to 500 watts (when connected to an 8 ohm load) to serve as a monophonic amplifier thus upgrading the output and satisfying the demands for a wide dynamic range that is essential in the present era.
To obtain a high-quality reproduction, good quality of low level signals is vital. The P-300L is provided with Class A driver stages. MOS FET driver circuitry, and output circuitry free from crossover distortion to maintain excellent sound quality of low listening level.
The P-300L can be combined with not only the C-200L Stereo Control Center but also any model of Accuphase pre amplifier.
Power output: 170 watts per channel into 8Ω (stereo), 500W into 8Ω (mono)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.01%
Damping factor: 300
Input sensitivity: 1.5V
Signal to noise ratio: 120dB
Speaker load impedance: 2Ω to 16Ω
Semiconductors: 56 x transistors, 12 x FET, 8 x IC, 78 x diodes
Dimensions: 445 x 160 x 373mm
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