Accuphase E-307
¥ 280,000 (released in December 2000)
Commentary
This is a pre-main amplifier that aims for higher perfection by refining the E-306V and gathering the design technology accumulated up to now.
The output device uses a multi-emitter high-power audio power transistor with excellent high-frequency characteristics, linearity of current amplification factor, switching, and other characteristics.
This element is composed of parallel push-pull to reduce impedance, and is fixed on a large heat sink for efficient heat radiation processing.
Both the preamp and power amplifier sections employ a current feedback amplifier circuit with superior high-frequency phase characteristics.
This circuit detects a current by reducing the impedance of the input terminal on the feedback side, and converts the current to I-V (current-voltage) with a transimpedance amplifier to produce an output signal. Since the impedance of the feedback input part is low, phase rotation hardly occurs and phase compensation is hardly necessary.
Therefore, various characteristics can be greatly improved with a small amount of NFB, and more natural energy response can be obtained.
The line amplifier section uses a pure complimentary service push-pull circuit composed of discrete parts, which is used as a current feedback amplifier circuit.
As a result, the phase compensation of each stage is lightened and natural sound quality is obtained.
A logic relay control method is adopted to enable the shortest and straight signal path.
The relay used in this system is a closed-type relay for the communication industry. By using a gold-plated cross-bar twin system for the contact, low contact resistance and high durability are obtained.
The tone control is equipped with an additive active filter tone control.
In this method, an original flat signal is passed straight through, another characteristic is created as necessary, and the sound quality is adjusted by adding or subtracting from the flat signal.
Equipped with two types of speaker terminals, it can be used separately or by wiring connection by switching the speaker selector.
A large power transformer of approximately 500 VA is used for the power supply section, and two aluminum electrolytic capacitors of 22,000 μ F are installed for the filter.
In addition, a dedicated power supply circuit is used for the preamplifier section that handles small signals to prevent interference with the power amplifier through the power supply section.
The preamp section and power amplifier section are separated from each other in terms of internal structure and layout to prevent mutual interference.
A logarithmic compression type analog peak power meter is installed to monitor output power.
Equipped with equipped with a separate switch and input / output terminal so that the preamp section and power amplifier section can be used independently.
Balance input is also installed in the input terminal.
Comes with a remote commander that allows volume adjustment and input selector switching.
Digital input and playback of analog records are possible by adding an option board.
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Model Rating
| Type | Integrated stereo amplifier | ||||||||||||||||||||
| Rated continuous average power (both channel operation, 20 Hz to 20 kHz) |
140W/ch (4 Ω) 120W/ch (6 Ω) 100W/ch (8 Ω) |
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| Total harmonic distortion factor (both channel operation) | 0.01% (4 Ω ~ 16 Ω Load) | ||||||||||||||||||||
| IM distortion factor | 0.01% | ||||||||||||||||||||
| Frequency characteristic | High Level input, Main input : 20 Hz ~ 20 kHz + 0 -0.2 dB (at rated continuous average output) 2 Hz ~ 150 kHz + 0 -3.0 dB at 1W Output |
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| Damping factor | 100 (8 Ω load, 50 Hz) | ||||||||||||||||||||
| Input Sensitivity / Impedance (Rated Output / EIA1W Output) |
High Level input : 113mV/11.2mV/20k Ω Balanced input : 113mV/11.2mV/40k Ω Main input : 1.13V/112mV/20k Ω |
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| Output Level / Impedance | Pre output : 1.13V/50 Ω (at rated continuous output) | ||||||||||||||||||||
| Gain | High Level input → Pre output : 20 dB Main input → output : 28 db |
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| S/N, input conversion noise |
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| Tone control | Bass (300 Hz) + / - 10 dB (50 Hz) High tone (3 kHz) : ± 10 dB (20 kHz) |
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| Loudness compensator | + 6 dB (100 Hz, Volume -30dB) | ||||||||||||||||||||
| Attenuator | -20dB | ||||||||||||||||||||
| Power meter | Logarithmic compression type peak level display Direct reading of output at dB scale and 8 Ω load |
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| Load impedance | 4 Ω ~ 16 Ω | ||||||||||||||||||||
| Headphone port | Applicable Impedance : 4 Ω ~ 100 Ω | ||||||||||||||||||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||||||||||||||||||
| Power consumption | 50W (without input) 240W (Electrical Appliance and Material Control Law) 385W (at 8 Ω load rated output) |
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| Maximum external dimensions | Width 475x Height 170x Depth 424 mm | ||||||||||||||||||||
| Weight | 21.4kg | ||||||||||||||||||||
| Attachment : Remote Commander RC-20 | |||||||||||||||||||||
| Remote control system | Infrared pulse system | ||||||||||||||||||||
| Pwer | DC 3V | ||||||||||||||||||||
| Dry battery | AA Type, 2 pcs | ||||||||||||||||||||
| Maximum external dimensions | 55 mm wide x 194 mm high x 18 mm deep | ||||||||||||||||||||
| Weight | 100g (including dry batteries) | ||||||||||||||||||||
| Optional Board Sold Separately | |||||||||||||||||||||
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