Интегральные усилители — Accuphase E-4000

The E-4000 is a stereo integrated amplifier from Accuphase, the Yokohama company founded in 1972 that builds all its components in Japan. It sits in the middle of the Accuphase integrated range, rated at 180 W per channel, and is built from technology developed for the brand's separate preamplifiers and power amplifiers, with the preamplifier and power sections clearly separated 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 0.01%. Frequency response is 20 Hz to 20 kHz (+0/-0.2 dB), and the damping factor is 800 into 8 ohms. Over a wider tolerance, response extends from 3 Hz to 150 kHz, and signal-to-noise reaches 125 dB. Gain is 18 dB from line input to pre-out and 28 dB from main-in to 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

Volume control uses AAVA, the Accuphase Analog Vari-gain Amplifier, an analogue gain-switching circuit that sets level without passing the signal through a resistive potentiometer track. In the E-4000, AAVA is combined with ANCC, a noise and distortion cancelling circuit. The power amplifier section is configured as an instrumentation amplifier with balanced transmission, which rejects common-mode noise between stages. The output stage uses four parallel push-pull pairs of power transistors per channel in Class AB. A large high-efficiency toroidal transformer and high-voltage filter capacitors supply the output stages, and protection uses MOS-FET switches instead of mechanical relays, removing contact wear from 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 is included.

Pairing

The high damping factor and power reserve into 4 ohms let the E-4000 drive low-sensitivity floorstanders and 4 ohm designs in rooms of 30 m2 and more. Optional Accuphase slot boards add a DAC or a phono stage, so digital sources and turntables can be connected without outboard units.

Alternatives

Accuphase's E-5000 is the larger integrated amplifier above it with a higher output rating and more powerful supply.