Audio Database


Accuphase E-407
400,000 yen(October, 1999 release)


The Integrated Amplifier of the new reference model which supplied the design technique, the newest circuit, and quality element which the Accuphase cultivated, and was developed aiming at the highest peak of an Integrated Amplifier.

The power transistor for multi-emitter type large electric power audios excellent in many characteristics, such as the high frequency characteristic, a current gain linearity, and switching, is adopted as an output element.
This element is constituted from a 3 parallel push pull, low impedance-ization is attained, and effective heat dissipation processing is carried out by fixing on a large-sized heat sink.

The preamplifier part / power amplifier part has adopted the current feedback magnification circuit which was excellent in the high region characteristic.
This circuit lowers the impedance of the input terminal by the side of a return first, detects current, carries out I-V (current-voltage) conversion of that current with a transformer impedance amplifier, and is making the output signal. In this circuit, since the impedance of a return input portion is very low, it is hard to generate phase rotation and there is almost no necessity for a phase guarantee.
For this reason, since many characteristics are sharply improvable by a little NFB, it excelled in dynamic characteristics, such as a standup, and the natural energy response has been obtained also in respect of sound quality.

The line amplifier part consists of discrete parts by a current feedback magnification circuit.
Foundations are the differential pure complimentary push pulls which are the original of an Accuphase, prepare a single ended push pull type emitter follower in an output stage, and are constituted comparatively simply.
Thereby, phase compensation of each stage is also light and the sound quality improvement is aimed at.

Since a straight signal course is constituted at the shortest, the logic relay control system which controls a relay electronically has been adopted.
The sealed type for communication industry was adopted as the relay used for this, and low contact resistance and quantity durability are realized by making a contact into a plated with gold and a crossover twin system.

The added type active filter system is adopted as tone control.
It passes straight, and if needed, this system is another, makes the characteristic, and is making the original flat signal adjust it from a flat signal.

The large-sized Troy Dahl type transformer of the large power capacity of about 600 VA(s) is carried in the power-source part, and also it excels in heat conduction, and using the high load material of the vibrationproofing effect, it adheres to the aluminum case of efficient heat dissipation structure, and the influence on the exterior is intercepted.
In order that a toroidal transformer may coil thick copper wire around a doughnut-like core,Since it is small, and the toroidal transformer of the Max ring type is adopted as E-407 in which conversion efficiency has the features, like it is high, the section of an iron core is [ impedance is very low, ] close to a circle and adhesion nature of a coil is closely good circularly,A loss can make weight light few, and the leakage flux is small and makes a roar and vibration smaller. Furthermore, iron loss and in rushes current are small suppressed by enlarging the rate of a bulk density of copper wire for the cross-sectional area of an iron core small.
Moreover, two 33,000-micro F things are carried in the aluminum electrolytic capacitor for filters.

The amplifier only for headphone is formed and consideration is carried out to the sound quality of headphone.
It is possible to cut the output to a speaker with a speaker selector, and to carry out variable [ of the headphone output ] in main volume.

It is begun to delete brass Naked material in a speaker terminal, it is formed into a golden plate in it, and the large-sized speaker terminal which can respond also to a thick cable is carried in it.
Two speaker outputs are carried and the use to change and bi-wiring connection are possible.

The logarithm compression type analog type large-sized peak power meter is carried.
This meter also carries the on/off switch of lighting.

Two balance inputs are carried.

The separate switch and input-and-output terminal which can carry out independent use of a preamplifier and the power amplifier are carried.

The remote commander in whom operation of volume and an input change are possible is attached.

The slot for option boards is carried and it can extend on the board of an AAB standard (Accuphase Analog Bus) standard according to a use.

Rear Option
A Power
Power Relay Speaker Balance

Rating of a mode
Form Integrated stereo amplifier
Rated continuation average output
(Both channel operation, 20Hz - 20kHz)
260 W/ch (4ohms)
220 W/ch (6ohms)
180 W/ch (8ohms)
THD (both channel operation) 0.02% (4ohms - 16-ohm load)
IM distortion 0.01%
Frequency response High Level input, Main input :
20Hz-20kHz+0 -0.2 dB (at the time of a rated continuation average output)
2Hz-150kHz+0 -3.0dB (at the time of 1W output)
Dumping factor 120 (8-ohm load, 50Hz)
Input sensitivity/impedance
(An Output power / EIA1W output)
High Level input: 158mV/11.2mV/20kohm
Balanced input: 158mV/11.2mV/40kohm
Main input: 1.58V/112mV/20kohm
An Output voltage/impedance Pre output: 1.58V/50 ohm (at the time of a rated continuation output)
Gain High Level input -> Pre output: 20dB
Main input -> output: 28dB
S/N, input conversion noise
Input short-circuit and A-compensation EIA S/N
At the time of an Output power S/N Input conversion noise
High Level input: 113dB -130dBV 82dB
Balanced input: 92dB -108dBV 82dB
Main input: 128dB -124dBV 103dB
Tone control Low-pitched sound (300Hz): ±10dB (50Hz)
Loud sound (3kHz): ±10dB (20kHz)
Loudness Compensation + 6dB (100Hz, Volume-30dB)
Attenuator -20dB
Power meter Logarithm compression type peak level display
dB scale and the output Direct reading at the time of 8-ohm load
Load impedance 4ohm-16ohm
Headphone jack Conformity impedance: 4ohms - 100ohms
Power source AC100V, 50Hz/60Hz
Power consumption 45W (at the time of no inputting)
410W (Electrical Appliance and Material Control Law)
605W (at the time of an 8-ohm load Output power)
The maximum Dimensions Width 475x height 180x depth of 423mm
Weight 23.7kg
Attachment: Remote commander RC-20
Remote control system Infrared pulse system
Power source DC 3V
Battery AA -- type and two pieces
The maximum Dimensions Width 55x height 194x depth of 18mm
Weight 100g (Battery includeded)
Option: Option board
With no picture Line-in board Line-9 (6,000yen)
The common high-level input terminal of an imbalanced system.
Analog signals, such as CD player and a tuner, are played.

With no picture Analog disc input board AD-9 (30,000yen)
All cartridges are supported by loading of a high gain equalizer.
With an internal DIP switch, a MM/MC change, MC input impedance, and Subsonic-Filter on/off can be set up.

MM Gain: 36dB
Input impedance: 47kohm
MC Gain: 62dB
Input impedance: 10, a 30 or 100-ohm change
The Line-in board Line-10 (8,000yen)
The common high-level input terminal of an imbalanced system.
Analog signals, such as CD player and a tuner, are played.
The Analog disc input board AD-10 (50,000yen)
All cartridges are supported by loading of a highly efficient high gain equalizer.
With an internal DIP switch, a MM/MC change, MC input impedance, and Subsonic-Filter on/off can be set up.

MM Gain: 29dB
Input impedance: 47kohm
MC Gain: 60dB
Input impedance: 10, a 30 or 100-ohm change