Integrated amplifiers — Accuphase E-5000

The Accuphase E-5000 is a high-power Class AB integrated amplifier from Accuphase Laboratory of Japan, developed to mark the company's 50th anniversary. Accuphase places it at the head of its Class AB integrated range. A preamplifier section with Balanced AAVA volume control is combined with a power stage built on the instrumentation amplifier principle, so the circuit stays balanced from input to output. The current Accuphase integrated line also includes the E-4000 and E-3000 and the Class A E-800S and E-700.

Key specs that matter

Accuphase rates continuous output at 240 W per channel into 8 ohms and 320 W into 4 ohms, both channels driven from 20 Hz to 20,000 Hz, with total harmonic distortion of 0.05% into 4 to 16 ohms. The guaranteed damping factor is 1,000. At rated output, S/N reaches 111 dB via the line inputs and 126 dB via the power amp inputs. Connections include five line inputs and two balanced inputs, a recorder loop, balanced and unbalanced preamp outputs and power amp inputs, plus A and B speaker outputs. The chassis measures 465 x 211 x 502 mm and weighs 33.8 kg.

Engineering and use context

Rather than a variable resistor, the AAVA circuit creates several weighted versions of the input signal and sets volume by changing their combination, avoiding contact wear and keeping noise low at every position. The volume sensor behind the knob was developed in-house and is made by aluminium block extrusion. Each channel has its own large heat sink and five pairs of power transistors in parallel push-pull, working in Class AB, with current feedback topology for phase linearity at high frequencies. The power supply has a large toroidal transformer and two 40,000 uF/100 V filter capacitors. Low-impedance MOS-FET switches handle speaker protection. On the front panel are analogue output meters reading down to -50 dB, tone controls with summing active filters, a loudness compensator, per-input phase setting and a -20 dB attenuator, and the RC-250 remote is supplied. Two rear slots take option boards such as the AD-50 phono stage for MC and MM cartridges and the DAC-60 digital input board with two ESS ES9016K2M chips.

Pairing

The large power reserve suits demanding 4 ohm floorstanders, although speaker set B is rated only for 8 to 16 ohm loads. Separate preamp outputs and power amp inputs allow bi-amping with a second Accuphase power amplifier or use of the E-5000 as a power amplifier alone. A discrete headphone amplifier drives headphones of 8 ohms and above.

Alternatives

For Class A operation, Accuphase offers the E-800S integrated amplifier.