Интегральные усилители — Extraudio X251 MKII

The X251 MKII is a dual mono integrated amplifier from Extraudio that pairs a pure Class A preamplifier with the company's own EPAM power modules. The front panel carries only volume and input selection, and the unit is built in an aluminium and steel case that matches the width, height and depth of the brand's DAC1 MKII converter.

Key specs that matter

Extraudio rates output at 400 W per channel into 8 ohm and 800 W per channel into 4 ohm, with peak current of 40 A per channel. Frequency response is flat from 20 Hz to 50 kHz. Noise and dynamic range figures both pass 120 dB, THD plus noise is 0.003 percent at 1 kHz and 1 W, and the damping factor is above 1,000 into 8 ohm at 1 kHz and below. Voltage gain is 28 dB. Line level sources connect through four RCA sockets and one XLR socket, with input impedance of 60 kohm unbalanced and 120 kohm balanced. The chassis is 44 cm wide, 12 cm high and 40 cm deep and weighs 11 kg.

Engineering and use context

In the preamplifier, Extraudio uses its own XP3 circuit, which runs in Class A throughout. Power comes from EPAM amplification modules, which the maker lists at 89 percent energy efficiency, so the amplifier stays cool and draws under 0.5 W in standby. A dedicated AV processor input, available as both XLR and RCA, bypasses the volume control, letting the amplifier power the left and right speakers of a surround setup driven by an AV processor. An internal phono module for MM or MC cartridges can be fitted as an option. Two pairs of WBT binding posts from Germany allow bi-wiring. The front plate is 6000 series aluminium over a precision steel chassis. The supplied remote control has a battery recharged over USB and a stated range of 20 to 80 m. Mains input is 115 or 230 V at 50 or 60 Hz. The RMS power limit of the output section is quoted at 1,500 W. The balanced input runs at 6 dB lower level than the RCA inputs, so level differences between sources can be balanced by choosing the connection.

Pairing

With that power and current reserve the amplifier can drive low sensitivity and low impedance speakers, and the high damping factor keeps control of large woofers. The DAC1 MKII converter from the same maker completes a two box digital system, and the optional phono board covers turntable owners without an external stage.

Alternatives

The Extraudio X800 MKII is a hybrid valve integrated amplifier that can also take the optional MM and MC phono module.