Интегральные усилители — Atoll Electronique IN400 Evolution

Atoll's IN400 Evolution is a dual mono integrated model from Atoll Electronique of France. The brand's integrated range also includes the IN50, IN80, IN100, IN200 and IN300. It belongs to the 400 line alongside the PR400 preamplifier and the AM400 power amplifier, and it accepts optional plug-in boards for digital inputs and phono.

Key specs that matter

Atoll rates the output at 2 x 160 W RMS into 8 ohm and 2 x 300 W RMS into 4 ohm. The frequency response extends from 5 Hz to 100 kHz at -3 dB, and the rise time is 2 microseconds. Input sensitivity is 450 mV, input impedance is 357 kohm, the signal to noise ratio is 100 dB and THD at 1 kHz is 0.05%. Connections include 2 balanced XLR inputs, 5 RCA line inputs labelled AUX, CD, TUNER, DVD and TAPE, and 1 bypass input, plus a 6.35 mm headphone jack and a 12 V trigger output. The case measures 440 x 370 x 130 mm and weighs 19.5 kg.

Engineering and use context

A double mono layout is used throughout, with separate transformer windings for each channel and one volume attenuator per channel. The audio section is fed by a 1,050 VA toroidal transformer, a second small transformer powers the control systems, and the shielded filter bank totals 96,680 microfarads. Input stages use bipolar transistors, driver stages use Darlington pairs, and each channel has 8 MOSFET output devices. The chassis is 2 mm steel with a 10 mm aluminium front panel that is brushed, micro-blasted and anodised, while the side heatsinks are machined from solid aluminium blocks to absorb mechanical vibration as well as dissipate heat. An OLED display can be switched off, the button backlighting is configurable, and balance settings are stored in memory. Standby can be set either to a low consumption mode below 0.5 W or to a preheating mode that keeps the circuits ready for use. The bypass input allows the amplifier to be inserted into a home cinema system as a fixed-gain stage.

Pairing

The optional DA200 board adds coaxial, optical, USB-B and Bluetooth inputs at up to 24 bit and 192 kHz, and the simpler DA100 handles coaxial and optical only. For vinyl, the P100 phono board is switchable between MM and MC, while the P50 is MM only. The high output into low loads suits demanding low-impedance loudspeakers, and the Atoll CD200 Signature matches it in width and styling.

Alternatives

Atoll's IN300 is the next integrated amplifier below it in the same catalogue.