Audio Database


Accuphase E-405
350,000 yen(October, 1989 release)


The Integrated Amplifier which union-ized the preamplifier and power amplifier which became independent substantially, and constituted them that the limit of an Integrated Amplifier should be overthrown.

The output stage of a power amplifier part has 5-parallel push pull composition by ten output elements, and each element can adopt the thing of Pc(collector loss)130W, and can send out sufficient power also to low load.
In the drive stage which drives an output stage, while having adopted the two-step dregs cord direct connection circuit of a dregs cord push pull and a MOS FET dregs cord push pull and improving the high region characteristic by dregs cord connection, the distortion at the time of the Koide power is suppressed few by MOS FET.

All the magnification stages also including a preamplifier part consist of direct connection systems. Moreover, it has the changeover switch and input terminal for separating the Puri part and a power part and using it as independent amplifier.
Since there is a possibility that it may be amplified as it is, a big direct current may appear in an output, and a speaker may be damaged when direct-current voltage is impressed for a certain reason in that case, the unnecessary direct-current ingredient was cut and "direct-current servo system" has been adopted that direct-current drift of the amplifier by a temperature change itself should be stabilized.
The direct-current voltage which appeared in the output is detected, and the state of direct-current voltage zero is maintained by returning to an input.

As a function of a power amplifier part, the large-sized power meter which can supervise an Output voltage is equipped.
Output electric power can be supervised in the logarithm compression type peak meter arranged in the center of a panel.

Two speaker outputs are carried and it is controlled by large-sized relay, and with an A+B output, two lines become parallel and it can respond also to the bi-wiring which separated low-pitched sound and an inside loud-sound network.

In the high level flat amplifier of a preamplifier part into which the usual signals other than an analog disc are inputtedThe dregs cord bootstrap differential system constituted with low noise dual FET and a transistor is adopted, and the Miller effect distortion by the impedance of input apparatus or change of volume control volume is prevented simultaneously with high S/N.
Moreover, the XLR type balance connector is carried.

The equalizer amplifier equipped with the input circuit in consideration of the characteristic of the cartridge of each MM type / MC model for exclusive use is carried.
At the time of MM input, FET and the transistor which can maintain high input impedance over all the frequency bands constitute the dregs cord bootstrap difference input circuit in consideration of the Output voltage of MM cartridge and an Output load impedance being high.
On the other hand, at the time of MC input, since signal voltage is low and the S/N improvement is a primary importance theme, the dregs cord bootstrap difference input circuit which selected carefully and uses an element with little peculiar noise is constituted.
These changes were performed by the relay 1 and the relay 2, and the amplification degree which suited MM/MC simultaneously is chosen.

The power-source part which became independent of power amplifier completely is carried in the preamplifier part.
After it is using Troy Dahl Torrance of the low leakage flux for a power transformer and a high-speed diode rectifies, stabilization is attained by ± dual tracking series regulator.

Since a straight signal course is constituted at the shortest, a relay is installed in the place of a required signal course, and it is changing by a change adopting the logic relay control system which controls these relays electronically.
The encapsulated type relay developed as an object for audios is adopted especially as a relay. A contact is a crossbar twin system and has become low contact resistance and a thing of high durability.

An input change is a system which changes a relay electronically, only presupposed that it is to control a logic circuit by a commander, and has adopted the system which volume control also makes rotate a motor for manual volume so that sound quality degradation may not occur.

The tone control for which the added type filter was applied to tone control is developed and carried, and the influence on the characteristic or sound quality is further eliminated by adopting the quality element focused on sound quality.
Furthermore, an ON-OFF switch is formed, and at the time of OFF, it constitutes so that a circuit may be passed.
It passes straight, an original flat signal makes the characteristic if needed, and the principle of this circuit serves as a system of making it adjust from a flat signal.

Operation of recording etc. is also possible in FM, carrying the recording selector independently with the input selector, and hearing CD.
Moreover, dubbing between recorders and the copy switch made independently are carried.

The function of the Subsonic Filter which cuts super-low-pass noises which mix a sound on either side, such as a mode switch and an analog disc, the Compensation switch which reinforces the feeling of low-pitched sound at the time of small volume, a headphone jack, etc. is carried.

Rear Attached

Rating of a mode
Form Integrated stereo Integrated Amplifier
Continuation average output
(Bothchannel operation, 20Hz - 20kHz, 0.02% of distortion)
4ohm load: 250 W/ch
8ohm load: 170 W/ch
(Both v operation, 0.25W - a continuation output, 20Hz - 20kHz)
0.02% (4-16-ohm load)
IM distortion 0.01%
Frequency response
Main Amp Input: 20Hz-20000Hz+0 -0.2dB (at the time of an Output power)
0.5Hz-150000Hz+0 -3.0dB (at the time of 1W output)
High Level Input: 20Hz-20000Hz+0 -0.2dB (at the time of an Output power)
Low Level Input: 20Hz-20000Hz+0.2 -0.5dB (at the time of an Output power)
Dumping factor 150 (8-ohm load, 50Hz)
A rated input / input impedance
Input sensitivity Impedance
At the time of an Output power EIA (at the time of 1W output)
AD Input(MC): 0.14mV 0.011mV 100ohms
AD Input(MM): 4.38mV 0.335mV 47kohm
High Level Input: 143mV 10.8mV 20kohm
Balanced Input: 143mV 10.8mV 40kohm
Main Amp(unbal): 1.47V 110mV 20kohm
Main Input(bal): 1.47V 110mV 40kohm
The disc maximum input (1kHz, 0.005% of distortion) MM input: 300mVrms (Rec Out)
MC input: 9.5mVrms (Rec Out)
An Output power/Output load impedance Pre Output: 1.47V/200 ohm
Tape Rec Output: 143mV/200 ohms (AD)
Headphones: 0.36V, conformity impedance 4-100ohm
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: 124dB -121dBV 102dB
High Level Input: 110dB -127dBV 83dB
Balanced Input: 98dB -115dBV 83dB
AD Input(MM): 89dB -137dBV 80dB
AD Input(MC): 74dB -150dBV 78dB
Tone control Low-pitched sound: Turnover frequency 300Hz, ±10dB (50Hz)
Loud sound: Turnover frequency 3kHz, ±10dB (20kHz)
Loudness Compensation (Volume-30dB) +6dB(100Hz)
Subsonic Filter 17Hz, -12 dB/oct
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 4-16ohm
The semiconductor used Transistor: 85 pieces
FET: 22 pieces
IC: 30 pieces
Diode: 65 pieces
Power source 100V/117V/220V/240V, 50Hz/60Hz
Power consumption At the time of no inputting: 90W
Electrical Appliance and Material Control Law: 390W
At the time of an 8ohm load Output power: 620W
Dimensions the width 475x height 180(piece -- it includeds) x depth of 375mm
Weight 25kg
Attachment: Remote commander RC-3
Remote control system Infrared pulse system
Power source DC 3V
Battery SUM-3 (an IEC name, R6), two pieces
The maximum Dimensions Width 64x height 149x depth of 18mm
Weight 140g (Battery includeds)