Integrated amplifiers — Accuphase E-4000

The Accuphase E-4000 is a two-channel integrated amplifier made by the Yokohama company founded in 1972, which builds all its components in Japan. It sits in the middle of the Accuphase integrated range. It uses technology developed for the brand's separate preamplifiers and power amplifiers, with preamplifier and power stages laid out as clearly separate sections inside the chassis.

Key specs that matter

Continuous output is 180 W per channel into 8 ohms and 260 W into 4 ohms from 20 Hz to 20 kHz. THD is 0.05% into loads of 4 to 16 ohms, and intermodulation distortion is 0.01%. Frequency response is 20 Hz to 20 kHz (+0/-0.2 dB), extending from 3 Hz to 150 kHz over a wider tolerance, and the damping factor is 800 into 8 ohms. Signal-to-noise reaches 125 dB. Gain is 18 dB from line input to pre-out and 28 dB from main-in to the speaker output, and the pre-output delivers 1.51 V at 50 ohms. There are two balanced and six unbalanced inputs. Idle consumption is 54 W and standby 0.3 W. The chassis measures 465 x 181 x 420 mm and weighs 24.9 kg.

Engineering and use context

Accuphase handles volume with AAVA, its Analog Vari-gain Amplifier, an analogue gain-switching circuit that adjusts level without passing the signal through a resistive potentiometer track. In the E-4000, AAVA works together with ANCC, a noise and distortion cancelling circuit. The power amplifier section is built as an instrumentation amplifier with balanced transmission, which rejects common-mode noise between stages. Each channel has a Class AB output stage with four parallel push-pull pairs of power transistors. A large high-efficiency toroidal transformer and high-voltage filter capacitors feed the output stages. Protection relies on MOS-FET switches instead of mechanical relays, so there are no wearing contacts in the speaker path. Bass and treble controls, loudness compensation and a -20 dB attenuator are provided, and the pre and power sections can be used separately. The RC-250 remote control is included.

Pairing

The high damping factor and the power reserve into 4 ohms make the E-4000 suitable for low-sensitivity floorstanders and 4 ohm designs. Optional Accuphase slot boards add a DAC or a phono stage, so digital sources and turntables connect without outboard units.

Alternatives

Higher up the range sits the Accuphase E-5000, a bigger integrated model with a higher output rating and a more powerful supply.