Arcam FMJ A49 Integrated Amplifier

The Arcam Way

Equipment report
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Integrated amplifiers
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Arcam FMJ A49
Arcam FMJ A49 Integrated Amplifier

The competition among today’s premium integrated amplifiers has all the drama and intensity of a season of Game of Thrones, with the exception of the blood spatters. This popular segment of components has the top electronics companies seeking dominion over your listening room, frequently at premium prices (and beyond). However, that’s not the way of Arcam. For decades the British brand has represented sonic sophistication fit for nobility at commoner prices. Like rival NAD, Arcam tends toward modesty, flying a little under the high-end radar. Historically, it has eschewed trendier bells and whistles for the cleaner design and shorter signal paths that lead to a purer, more authentically musical presentation. Its latest, the A49, represents the brand’s top-tier integrated from its FMJ Series. (For the record, FMJ stands for “Faithful, Musical, Joy” and not the title to the 1987 Stanley Kubrick film.)

A full-featured, high-powered integrated, the A49 represents the zenith of Arcam’s engineering efforts in this segment. Its basic DNA and general topographical features and circuitry are shared by its matching cousins, the C49 preamp and P49 power amp—the latter being a perfect partner should an A49 owner consider bi-amping down the road.

The A49’s calling card is power and lots of it. It outputs a hefty 200Wpc into 8 ohms (400Wpc into 4 ohms) and, significantly, fifty of those watts in pure Class A mode. This is all thanks to Arcam’s latest-generation Class G topology. Class G? Simply stated, Class G is a version of Class AB that, in the pursuit of higher efficiency, “uses multiple power supply rails of various voltages and automatically switches between these supply rails as the input signal changes.” Arcam gives this example: Under low-demand conditions, the system utilizes a lower rail voltage than a comparably rated Class AB amplifier, significantly reducing power consumption. When more power is demanded, extra transistors come into play as the system switches to the high voltage rail. This technique reduces the average power consumption, and loss caused by wasted heat.

The A49 preamp section features a four-layer fiberglass PCB, with separate ground and power planes for optimum layout of signal traces. All resistors in the main signal path are 0.1% thin-film, surface-mount parts. This ensures accurate channel matching and stable resistor values. The preamp’s power supplies rely on a dedicated toroidal transformer, entirely separate from the massive 1.5kVA one used for the power amplifier. The transformer feeds ten separate regulated supplies for the preamplifier and its control switches. Surface-mount components are used extensively. In addition, the low-level audio signals are handled in balanced mode throughout the preamplifier; the balanced circuit’s common-mode rejection isolates the preamp’s circuitry from the high-current swings of the power amplifiers and their supplies. The A49 employs an electronic dual-mono volume control with ladders of resistors to eliminate the imbalances and long-term wear of rotary pots.

The A49’s front panel is spacious—eye-catching in the vertical arc that softens its imposing height. Controls are centralized around the hefty volume knob and horizontal display. They include input selection buttons on the left and additional inputs, mute, balance, and speaker indicators to the right. A 3.5mm headphone mini-jack completes the array. Arcam notes that the front-panel display and general operating features, including overload protection, are under the control of a microprocessor housed at one end of the preamp PCB. It is fed from the +5V standby power supply and isolated from the analog sections.

The back panel is equally roomy with seven RCA inputs, a pair of balanced XLR inputs and XLR pre-outs, a trigger output, and dual sets of speaker terminals. Happily, the A49 is also equipped with a 47k-ohm phono input designed to accommodate standard moving-magnet cartridges. By now, Arcam should be hip to the fact that many of today’s interconnects use fairly thick terminal jackets. So, with all that available room on the back panel, how about a little more spacing between each right and left input, lads? A full-function remote control is included, as well.

Unlike some of its rivals, the A49 doesn’t offer an internal USB/DAC, optional or otherwise. However, the back panel is equipped with an on-board power supply to power Arcam’s 6V and 12V rSeries products, which include wireless and standard DACs. Not a bad idea either—offering the capability of adding a standalone DAC at the owner’s discretion, and keeping potential noise-inducing digital circuitry outside the A49 chassis.

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