Audio Database


Accuphase E-406
380,000 yen(June, 1993 release)


The Integrated Amplifier which the Accuphase concentrated the development technology cultivated for years by the separate amplifier group, made the preamplifier part and the power amplifier part become independent completely, and was developed as a form of the ideal of integrated amplifier.

a power amplifier part -- an output stage -- 4 -- it constituted from a parallel output element, this was attached to the large-sized heat sink, and the operational stability also corresponding to low impedance load has been obtained.
In order to prevent output offset voltage (phenomenon which a part flowed in one direction leaks to an output), by using an Accuphase and original direct-current servo amplifier for NFB (return circuit), a speaker output was not made to generate a part flowed in one direction, but operation stabilized also in power source variation or a temperature change has been obtained.

The input circuit is constituted from an Accuphase original differential complimentary push pull circuit, and has realized high CMRR (this phase ingredient removal ratio).
This differential part is the push pull amplifier of emitter grounding by which Darlington connection was made, and the signal is led to the driver part of an output stage. By push pull composition symmetrical with the bottom of besides, high operational stability is made possible.

The transformer of power amplifier / preamplifier part independence was used for the power-source part, and the mutual intervention between amplifier is completely prevented by using an exclusive power source, respectively.
The thing of the heavy weight class which amounts to 9kg is adopted as the power transformer for power amplifier, and the mass capacitor of 33,000 micro Fx2 is adopted as smooth.

The large-sized speaker terminal which can respond also to a very thick cable and which began to delete brass Naked material is adopted as a speaker terminal. This terminal also supports the banana plug.

Furthermore, bi-wiring connection is also supported by choosing an A+B position.

The large-sized power meter which can monitor output electric power is carried.
this meter -- logarithm compression -- it is possible to supervise correctly the music signal which changes since a large dynamic range can be seen at once since type, and it moreover supplements with a peak.

The line amplifier part is constituted from a discrete part, and basic composition is the original of an Accuphase, and a differential pure complimentary push pull, prepares a single ended push pull type emitter follower in an output stage, and is considered as simple composition. Phase compensation of each stage also became light by this, and more natural sound quality has been obtained.
Moreover, the cross talk from a main power supply is coped with using a local active ripple filter power source.

The composition equipped with the input circuit in consideration of the characteristic of the cartridge of each MC type / MM model for exclusive use is adopted as an equalizer amplifier part.
At the time of MM input, it constitutes from an FET element which can maintain high input impedance over all the circumferential fraction zones in consideration of an Output voltage and an Output load impedance being high. Moreover, at the time of MC input, since a minute signal is received by low impedance, little reproduction of noise is enabled by a low noise element's constituting a difference input circuit, and attaining low impedance-ization of a NFB loop.

The golden plate is adopted as the print board of main signal courses, in order to raise the purity of circuit wire connection and to aim at improvement in sound quality.
Copper of high purity is used for the printed circuit board, by performing golden plate-ization on this, the influence of a skin effect was reduced and the good degree of electric conduction has been obtained.

Since a straight signal course is constituted at the shortest, the change installed the relay in the required place and has adopted the logic relay control which controls these relays electronically.
The encapsulated type relay containing nitrogen gas for communication industry is adopted as the relay used for this. This relay contact has acquired low contact resistance and quantity durability by the plated with gold and the crossbar twin system.

Tone control of the added type active filter system used for a full-scale graphic equalizer is developed and carried in the tone control part.
By this system, it passes straight, if needed, an original flat signal is another, makes the characteristic, is a system adjusted from a flat signal, and serves as a system which excelled the conventional tone control in the field of sound quality.

The remote commander in whom an input change and volume control are possible is attached.
Since the input selector has adopted the system which changes a relay electronically, it is controlling this logic circuit by a commander, and there is no degradation of sound quality.
Furthermore, especially, the adjustor of an input level adopts the small resistance object of a distortion, is considering it as the type which this resistance object rotates, attaches a gearing system and an electric motor to this, and supports remote control. The magnetic shield is given to the exterior covering of this motor with the silicon steel plate, and the influence by noise is reduced.
Since the micro computer is used and the timing of a change is controlled to the milli second (ms) order, there is no generating of change noise.

The balance input is carried.
In balance transmission, the sending side transmits simultaneously the signal of the plus which the phase reversed 180 degrees on the same voltage, and minus, and, in response, the receptacle side is correctly compounded with + amplifier and - amplifier. It will be canceled if compounded, and only the amount of noise disappears, and the purity of a music signal goes up the noise ingredient generated in a cable at this time in order to go into two poles at this phase.

The amplifier only for headphone is formed and sound quality is considered.

A preamplifier part and a power amplifier part are separated and the changeover switch and its input-and-output terminal for using it as independent amplifier are carried.

Power Speaker Golden
Block Power The
Input-and-output Balance

Rating of a mode
Form Integrated stereo amplifier
Continuation average output (both channel operation)
20Hz - 20kHz, 0.02% of a distortion
250 W/ch (4ohms)
170 W/ch (8ohms)
THD (both channel operation)
0.25W - a continuation output, 20Hz - 20kHz
0.02% (4ohms - 16-ohm load)
IM distortion 0.01%
Frequency response
Main amp input: 20Hz-20kHz+0 -0.2dB (at the time of an Output power)
2Hz-150kHz+0 -3.0dB (at the time of 1W output)
High Level input: 20Hz-20kHz+0 -0.2dB (at the time of an Output power)
Low Level input: 20Hz-20kHz+0.2 -0.5dB (at the time of an Output power)
Dumping factor 120 (8-ohm load, 50Hz)
Input sensitivity/impedance
(An Output power / EIA1W output)
AD input(MC): 0.15mV/0.011 mV/100 ohms
AD input(MM): 4.65mV/0.35mV/47kohm
High Level input: 147mV/11.2mV/20kohm
Balanced input: 147mV/11.2mV/40kohm
Main input: 1.47v/112mV/20kohm
The Disc maximum input
(Rec out, 1kHz, 0.005% of distortion)
An Output power/impedance Pre output: 1.47V/50 ohm
Tape Rec output: 125mV/200 ohms (AD)
Gain Main input -> output: 28dB
High Level input -> Pre output: 20dB
AD input (MM) -> Tape rec output: 30dB
AD input (MC) -> Tape rec output: 60dB
S/N, input conversion noise
Input short-circuit and A-compensation EIA S/N
At the time of a rated input S/N Input conversion noise
Main amp input: 130dB -127dBV 108dB
High Level input: 113dB -130dBV 84dB
Balanced input: 90dB -108dBV 84dB
AD input(MM): 90dB -137dBV 80dB
AD input(MC): 75dB -151dBV 80dB
Tone control Low-pitched sound (300Hz): ±10dB (50Hz)
Loud sound (3kHz): ±10dB (20kHz)
Loudness Compensation + 6dB (100Hz, Volume-30dB)
Subsonic Filter 17Hz, -12 dB/oct
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/117V/220V/240V, 50Hz/60Hz
Power consumption 65W (at the time of no inputting)
390W (Electrical Appliance and Material Control Law)
620W (at the time of an 8-ohm load Output power)
The maximum Dimensions Width 475x height 180x depth of 423mm
Weight 28.0kg
Attachment: Remote commander RC-10
Remote control system Infrared pulse system
Power source DC 3V
Battery UM-4 (an IEC name, R03), two pieces
The maximum Dimensions Width 66x height 175x depth of 20mm
Weight 190g (Battery includeds)