Интегральные усилители — Accuphase E-3000

The E-3000 is a Class AB integrated stereo amplifier from Accuphase Laboratory of Japan. The company describes it as the next-generation standard model that merges two earlier lines, the E-200 series and the more upmarket E-300 series, and it therefore replaces both the E-280 and the E-380. It carries over several circuits developed for the higher Accuphase models. Its American retail price is USD 8,975.

Key specs that matter

Rated continuous output is 100 W per channel into 8 ohm and 150 W into 4 ohm, with a guaranteed damping factor of 600, which Accuphase states is 20 percent above the figure of 500 for the E-280 and E-380. Harmonic distortion is given as 0.05 percent. The line inputs comprise one balanced XLR pair and five unbalanced RCA pairs. The chassis measures 465 mm wide, 161 mm high and 420 mm deep and weighs 23.1 kg, which makes it the smallest Class AB integrated in the current Accuphase range yet heavier than the E-380. Two rear slots take option boards, the DAC-60 digital input board and the AD-60 phono board, which offers 66 dB of gain for MC and 40 dB for MM and four MC input impedance settings, including a new 200 ohm position.

Engineering and use context

The volume control is the Accuphase Analog Vari-gain Amplifier circuit, or AAVA, which converts voltage to current and back instead of using a variable resistor. In the E-3000 this module runs five buffer amplifiers in parallel together with the ANCC noise and distortion canceling circuit, and Accuphase quotes 20 percent lower noise than the E-380 at the nine o'clock volume position. The buffers sit close to the input jacks to reduce induced noise. Each channel has its own power amplifier module on either side of a custom transformer and two 33,000 uF filter capacitors. The output stage uses three parallel push-pull pairs of bipolar transistors rated at 15 A and 230 V, and a balanced remote sensing loop feeds back both signal and ground from points next to the speaker terminals. Speaker protection uses a MOS-FET switch with 1.6 milliohm on-resistance instead of a mechanical relay, while photo-couplers and heatsink temperature sensors cut the output and flash the large analogue power meters when a fault occurs. Tone controls use summing active filters.

Pairing

Two pairs of large speaker terminals are fitted, and the low output impedance suits speakers with low or strongly varying impedance. With the AD-60 fitted, a turntable connects without a separate phono stage.

Alternatives

The Accuphase E-4000 is a Class AB integrated rated at 180 W per channel with a four-fold parallel push-pull output stage and a damping factor of 800.