Усилители мощности стерео — Linn Akurate 4200

The Akurate 4200 is the four-channel member of Linn's Akurate power amplifier family, which also includes the two-channel 2200 and the three-channel 3200. The first edition of the owner's manual for the range dates from May 2007, and the amplifier stayed in the catalogue in an updated chassis. Linn built the family for owners who want to add channels as a system grows, whether for stereo, multi-channel or active use. The Australian list price of the current version is AUD 12,995.

Key specs that matter

Every channel is rated at 200 W RMS into 4 ohms and 111 W RMS into 8 ohms, and Linn states the design is unconditionally stable into all loudspeaker loads. Linn quotes a frequency response of 1.4 Hz to 41 kHz, harmonic distortion below 0.005 percent and a peak output voltage of 41 V. Input impedance is 7.5 kilohms on the RCA version and 7.8 kilohms on the XLR version, with clipping reached at 1.1 V and 2.2 V respectively. Maximum continuous draw from the mains is 300 W. The current chassis measures 380 mm wide, 91 mm high and 380 mm deep and weighs 8.3 kg, in silver or black, while the original was 381 x 355 x 80 mm and 6.9 kg.

Engineering and use context

Each channel uses Linn's patented Chakra topology, in which a group of large bipolar transistors act as boosters around a single-chip amplifier IC. Below a few amps of output current the chip supplies everything, and above that the transistors carry most of the current, leaving the IC free to correct errors. Linn says this keeps the signal path short and produces less heat than conventional output stages. The amplifier runs from a switch-mode supply that accepts any worldwide mains voltage without adjustment, and from July 2009 Linn moved its amplifiers to the Dynamik version of that supply, which it credits with 30 percent more RMS output in power amplifiers. Signal sensing wakes the amplifier when music arrives and drops it to standby after roughly 20 minutes of silence. Over-current and over-temperature protection shut affected channels down and restart them automatically. A channel can be converted to Aktiv duty by fitting a Linn Aktiv module, after which its rear gain control becomes usable.

Pairing

Four channels allow a pair of two-way loudspeakers to be driven actively with Aktiv crossovers, or a pair of speakers to be bi-amped, or two stereo zones to be covered from one box. RCA and balanced XLR versions exist, so the input type should match the preamplifier or streamer. An audio output on each channel can pass the signal to another amplifier or a subwoofer. In Exakt systems each channel can power one driver section.

Alternatives

Linn's Akurate 2200 offers the same Chakra channels and power rating in a two-channel chassis.