The E-4000 is a succession model of E-480, the 12thgeneration Accuphase Class-AB high-power integrated
stereo amplifier.
The Preamplifier section provides a low-noise AAVA
volume control with a fully refined circuit configuration andlayout.
The Power amplifier section adopted the bipolartransistors in a four-fold parallel push-pull arrangement
and made a significant achievement for the driving abilityof loudspeakers.
The E-4000 extracts the full potential of any loudspeaker
to reproduce sound overflowing with energy and vividness.

1The front face design has changed from the E-480, withthe large power meters in the big glass window
surrounded by precise cutting work and the gold-platedrings set at the bottom of the input selector and thevolume knob.

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E-4000 has a mono-block construction.
A strong power supply with a massive, specially-made,high-efficiency toroidal transformer and 40000μF filtering
capacitors are installed in the unit's center.
In addition, the two power amplifier modules are kept
separate for the left and right channels.
The AAVA module is set at the front of the unit to avoid
noise interference.

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The E-4000 has the second highest output power in
Accuphase integrated amplifiers, and the rated
continuous average output power is 180W/8Ω.
The E-4000 perfectly drives any loudspeakers, even lowefficiency ones.
*Rated continuous average output power is equal to theE-480

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AAVA (Accuphase Analog Vari-gain Amplifier) is a volumecontrol principle that eliminates all variable resistors fromthe signal path.
This AAVA volume control is Accuphase's unique
technology.
The E-4000's AAVA module contains six paralleled buffer
amplifiers and the lower-impedance V to I converter andutilizes the ANCC, so the E-4000 achieved 20% lower
noise than the E-480.
*E-480's AAVA module has no ANCC and five circuits
paralleled in the buffer amplifier.

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For the E-4000, Accuphase thoroughly reviewed theAAVA implementations.
Placing the buffer amplifiers close to the input jacks, theE-4000 succeeds in reducing the noise induced between
the input jack and AAVA.
Thanks to this, the E-4000 achieves excellent
performance in the induction noise rejection, comparable
to the balanced AAVA module adopted for the highgrade pre-amplifiers.
*In the E-480, buffer amplifiers are arranged inside theAAVA module.
BufferampV to Iconverter

Left channel

Right channel

I to V converter

E-480 AAVA assembly
6The E-4000 achieves a guaranteed damping factor of800.
It is 33% higher than the former model E-480 and has
the same value as Class-A stereo power amplifier A-48.
*Damping-Factor, DF: An index of speaker driving ability.
A higher Damping-Factor amplifier has higher speakerdriving ability.
DF = 8 ohm / Output-impedance

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The Circuit configuration of the power amplifier engine isas same as the flagship Class-AB stereo power amplifier
P-7500.
The output impedance is lower by four-fold parallel pushpull output stage arrangements of bipolar transistors.
*E-480 has three-fold parallel push-pull output stage
arrangements of MOS-FET. Absolute maximum ratings of
E-480’s MOS-FET: 200V/12A

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Remote sensing is the technique to lower the amplifier's
output impedance by the negative feedback with signal
sensing from nearby the speaker terminals.
Balanced Remote-sensing is the technique to lower theoutput impedance by both the signal sensing and theGND senses.
Not only the Damping Factor but also Total Harmonic
Distortion and Intermodulation Distortion are all improvedby the Balanced Remote-sensing.

9Mechanical relays are the typical components forspeaker protection, but the contact resistance of
mechanical relays is higher than people think.
Therefore, Accuphase has chosen the MOS-FET switch
instead of conventional mechanical relays for speakerprotection.
Thanks to this MOS-FET switch, the damping factor,
reliability, and sound quality are all improved. E-4000
adopted a new MOS-FET with a very low on-resistanceof 1.6mΩ(E-480 used 2.0mΩ on-resistance MOS-FET).
E-4000 employs carefully-selected very low-impedancecomponents such as the large speaker terminals.
Making signal paths thick and short also helps attain lowimpedance.

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The newly designed output protection circuit can detect
any short-circuiting of the speaker terminals with due
consideration for product safety.
Temperature sensors that detect the heatsink
temperature are installed on the heatsink. Thanks to this,the unit accurately ascertains the high-temperature alarmin the power amplifier section.
Thanks to the photo-coupler, the detected short-circuiting
information is completely isolated from the music signal
to minimize the negative effects on the sound quality.
*When these protection circuits are activated, the unit
completely interrupts speaker output and makes thepower meters flash to indicate the abnormal condition.

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ANCC: "Accuphase Noise and distortion Canceling
Circuit" is installed in AAVA's current-to-voltage converter.
Canceling noise and distortion are realized by detecting
the components of noise and distortion at the input stageof an I-V converter circuit and by injecting the cancelingcurrent, which contains the reversed polarity of thosecomponents.
ANCC is a highly effective technology at any volume
position.

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