Accuphase
Premain amplifier
Accuphase
E-380
Manufacturer's warranty period: 5 years
AAVA (Accuphase Analog Vari-gain Amplifier) system with volume control
The main functions of the preamplifier are "input switching" and "volume control". Of these, volume control is the most important element that affects the sound quality.
The E-380 uses AAVA for volume control, a completely new concept of volume control that adjusts the volume without using a variable resistor.
AAVA adjusts the volume by combining the outputs of multiple V-I conversion amplifiers with different gain according to the volume position.
The volume is directly adjusted by the gain of the amplifier, resulting in a high signal-to-noise ratio and low distortion.
High signal-to-noise ratio and low distortion ratio due to direct volume adjustment by amplifier gain
Input buffer amplifier with 5-MCS
High signal-to-noise ratio is realized by 5-MCS, which operates 5 high-performance amplifiers in parallel.
The 5-MCS improves the drive capability of the heavily loaded V-I conversion amplifier to minimize the deterioration of strain rate.
V-I conversion amplifier with improved signal-to-noise ratio
The V-I conversion amplifier doubles the total output current and reduces noise by halving the impedance of the circuit.
In terms of components, more low-noise, high-precision thin-film resistors are used than in the previous model.
These improvements have resulted in a 2dB improvement in S/N at rated output and a 1dB improvement in EIA-S/N (down to 85%) compared to the previous model.
The top-level V-I conversion amplifier, which has the largest load, has four parallel circuits, and the next circuit has two parallel circuits to distribute the load and provide ample room for operation.
The highest-load V-I conversion amplifier has four parallel circuits, and the next circuit has two parallel circuits to distribute the load and improve stability and reliability by reducing heat concentration on the board.
Rated output increased by 20% by strengthening the power amplifier stage and power supply section
The power amplifier stage consists of two parallel push-pull configurations of NPN and PNP bipolar transistors.
Rated output power of 180W into 4 ohms and 120W into 8 ohms, equivalent to a 20% increase, despite the same size chassis as the previous model
Powerful power supply with large transformer and high-capacity filter capacitors
A large-capacity transformer has been developed to increase output power, and a 33.000μF high-capacity, high-quality aluminum electrolytic capacitor has been newly adopted for smoothing.
The preamplifier section, which handles small signals, is equipped with a dedicated power circuit to prevent interference with the power amplifier.
The internal structure also separates the preamplifier section from the power amplifier section to achieve an ideal operating environment with no mutual interference.
Power amplifier with instrumentation amplifier configuration
An instrumentation amplifier configuration has been introduced for the power amplifier section.
Balanced transmission of unbalanced input signals is realized in the basic circuit for amplification.
In addition to having excellent characteristics such as the ability to eliminate noise generated in the equipment and strain rate, the amplifier is also highly resistant to changes in the surrounding environment.
In addition, it is highly resistant to changes in the surrounding environment, further improving the stability and reliability of the power amplifier.
The power amplifier section is equipped with a "current feedback" amplifier circuit with excellent phase characteristics in the high frequency range.
◆Current feedback amplifier circuit is used to return the output signal in the form of current.
There is almost no change in frequency response even when the gain is changed, and the phase response in the high frequency range is excellent.
Damping Factor Increased by 25
The damping factor (DF) is the ratio of the output impedance of the power amplifier (Z) to the impedance of the speaker (R) (DF=R/Z).
The higher the value, the greater the ability of the amplifier to control the speaker.
In other words, the higher the DF, the shorter the time it takes to absorb the back EMF from the speaker, suppressing unwanted vibrations and achieving ideal speaker drive.
The E-380 has achieved a DF of 500, 25% higher than the previous model, by reviewing the components and patterns in the board.
Balanced Remote Sensing
Balanced feedback is applied to both the signal and GND from the speaker terminals to reduce the output impedance and improve the damping factor.
MOSFET switch for protection circuit
In the event of an amplifier malfunction, the protection circuit disconnects the speaker to prevent damage to the speaker.
In general, output relays with mechanical contacts are used, but they cause problems such as increased impedance due to oxidation of the contacts and deterioration of performance and sound quality.
The E-380 uses a "MOSFET switch" which has no contact points, thus solving the problem of aging and ensuring long-term reliability.
In addition, it prevents the deterioration of sound quality caused by music signals passing through the contacts.
The E-380 uses a MOSFET switch with a very high current rating (160A) and a very low ON resistance (0.002Ω).
The protection board is connected to the speaker terminals by a metal pole.
In order to keep the impedance lower, the protection board is directly connected to the speaker terminals by a very thick and short metal pole.
The result is an ideal feedback point close to the speaker terminals for improved damping factor and sound quality.
New speaker output protection circuit
In addition to the conventional protection circuitry that detects abnormal temperature rise and signals with high DC content, the new speaker output protection circuitry immediately shuts down the output in the event of excessive current flowing into the speaker terminals.
In addition to the conventional protection circuit that detects abnormal temperature rise and signals with high DC content, a new protection circuit is equipped that immediately shuts down the output and warns by flashing the meter illumination in the event of overcurrent to the speaker terminals.
Two speaker terminals are provided for connection of Y-rugs and banana plugs.
The preamplifier and power amplifier can be used independently.
A wide variety of input terminals and balanced connections that are less susceptible to external induced noise
Logic relay control signal switching system
Logic relay control signal switching system ◆Phase can be set individually for each input terminal
Additive active filter type tone control with emphasis on sound quality
Compensator" to compensate for audible bass deficiency
Analog peak power meter that displays up to -50dB
When the "DAC50" is installed, 32 to 384 KHz PCM and 2.8, 5.6, and 11.2 MHz DSD can be displayed.
Full-fledged headphone amplifier with emphasis on sound quality
Equipped with a slot for adding two option boards.
Specifications
Rated continuous average output: (Simultaneous operation of both channels between 20 and 20,000 Hz), 180 W/ch 4 Ω load, 120 W/ch 8 Ω load
Total harmonic distortion rate: (Simultaneous operation of both channels between 20 and 20,000 Hz), 0.05% into 4 to 16 Ω load
IM distortion rate: 0.01
Frequency response
HIGH LEVEL INPUT at rated continuous average output: 20 to 20KHz (0-0.5dB)
MAIN INPUT at rated continuous average output: 20 to 20KHz (0-0.2dB), 1W output: 3 to 150KHz (0-3.0dB)
Damping factor: 500 (8Ω load, 50Hz)
Input sensitivity (at rated output): HIGH LEVEL INPUT/155mV, BALANCED INPUT/155mV, POWER INPUT/1.23V
Input impedance: HIGH LEVEL INPUT/20KΩ, BALANCED INPUT/40KΩ, POWER INPUT/20KΩ
Output voltage: Output impedance PRE OUTPUT/1.23V/50Ω (at rated continuous output)
Gain: HIGH LEVEL INPUT →PRE OUTPUT: 18dB, POWER INPUT →OUTPUT: 28dB
Tone control (turnover frequency and variable range): Bass: 300Hz (±10dB/50Hz), treble: 3kHz (±10dB/20kHz)
Loudness compensator: +6dB (100Hz)
Attenuator: -20dB
Input Conversion Noise: Input Short (A-Corrected) HIGH LEVEL INPUT / -125dBV, BALANCED INPUT / -114dBV, POWER INPUT / -122dBV
S/N ratio: S/N at rated output, HIGH LEVEL INPUT/109dBV, BALANCED INPUT/98dBV, POWER INPUT/124dBV
Power meter: Logarithmic compression type peak level display, dB/% display of output
Load impedance: 4 to 16 ohms (A, B terminals), 8 to 16 ohms (when A, B output simultaneously)
Stereo headphones: Applicable impedance 8Ω or more
Power consumption: 46W without input, 292W Electrical Appliance and Material Safety Law, 423W at rated output into 8Ω load
Maximum external dimensions: (W) 465 x (H) 171 x (D) 422 mm
Weight: 22.8kg
Accessories: Remote commander: RC-230
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