Since the original A60 integrated amplifier was first produced in 1976, Arcam has expanded to produce an ever-growing, increasingly more interesting range of products, covering almost all aspects of hi-fi and AV equipment. During this time they have gained a fine reputation for performance and build quality across a wide spectrum of prices, and the FMJ (Faithful Musical Joy) range is claimed to reproduce an utterly convincing three-dimensional soundstage. All the current products have a black finish with understated clean styling.
This £4000 A49 is the top-of-the-range integrated amplifier (alongside a C49/P49 pre-/power combo for those who prefer an arguably more versatile alternative). It's designed in the UK, built in the USA, and has a Class G output stage producing a power output of 200W into an 8 Ohm load (both channels driven), all packaged in a relatively neat and compact case. The output doubles to give 400W into 4 Ohms (albeit with only one channel driven at 1kHz), and the amplifier is also designed to drive difficult 2 Ohm loads without stress. It's certainly powerful, and will be able to drive a wide range of loudspeakers to high levels, even those of low sensitivity.
The choice of adopting Class G is an interesting one. It was originally invented by Hitachi almost 40 years ago, but never really found favour with most hi-fi designers, mostly due to difficulties surrounding its implementation and making it sound good. An advantage of Class G is that it's highly efficient and produces less heat than the usual hi-fi amplifier using Class A or AB topology, so it's an obvious choice for AV amplifiers that need to squeeze lots of channels into one case, where the waste heat can become a problem. Advances in electronic technology have allowed Arcam to overcome the technical problems in making Class G work to its satisfaction, so it's used in its AV amps. Obviously Arcam then found that the design works so well that it was deemed good enough for its top hi-fi range.
The power amplifier design has two extra supply rails that allow the voltage to be switched from +/-35V to +/-65V when needed, so most of the time the standing power dissipation is halved. This allows the use of smaller heatsinks and casework. The power supply uses a 1.5kVA toroidal transformer and has two bridge rectifiers feeding 2x 22,000uF capacitors for the lower voltage and 2x10,000uF for the 65V rails. Fast, high current FETs are used to switch in the higher voltage rail, to track the needs of the output stage at a very high speed, so pushing any switching noise far beyond the audio bandwidth. The actual core of the amplifier is the more normal Class AB topology, using special bias circuitry and three pairs of high current ThermalTrak output transistors with integral bias diodes, driven by a Texas Instruments (TI) high voltage power amp driver. Arcam claims that the amplifier will run up to 50W into an 8 Ohm load in Class A.
The pre-amp is built on a single four-layer printed circuit board, its own power supply fed from a separate toroidal power transformer, and with ten regulated supplies for the pre-amp and control switches. An extra transformer winding also provides isolated +6V and +12V DC outputs for Arcam's various rSeries DACs. The boards are mostly populated with precision surface mount components but some through-hole devices are also used when thought necessary. Electronic input switching uses solid state multiplexers, and all the low level signals use balanced mode internally; single-ended input signals are converted to balanced operation as early as possible. Low noise TI operational amplifiers are used for the gain stages and two TI switched resistor ladder chip volume controls are used in differential mode to ensure low noise. Line level signals have a DC coupled path throughout with servo circuits employed to cancel any DC offsets. Specially selected capacitors are used throughout.
A moving magnet cartridge phono stage is included. It's designed around the same low-noise TI op-amp that's used in the line stages, but has a high pass filter (-3dB at 20Hz) to reject low frequency turntable rumble. A separate headphone amplifier is mounted on the front panel and is designed to have both a low output impedance and a high voltage drive capability in order to work with well with the vast majority of headphones. Four pairs of high quality gold plated loudspeaker 4mm socket/binders may be switched from the front panel, backed by a couple of status LEDs. A standard 10A IEC socket supplies mains electricity.
The pre-coated steel casework has a colour-matched aluminium front panel; a slot in the lower half presumably provides increased airflow for the internal, centrally mounted heatsink. A large centrally mounted knob controls volume, with clearly marked and sensibly located buttons on either side to control input and speaker switching. The power switch is close to the headphone socket on the right side. The top section has a dimmable display indicating volume and input, while buttons select and adjust the balance. (The volume can be configured as a balance control covering ±12dB). There are six single-ended line level inputs, a balanced input and also a pre-amp output from either balanced or phono sockets. A pair of phono sockets are marked ‘record out' (but without any tape monitor facility), and the cartridge input can be turned into another line level input in the menu if required. A couple of trigger outputs control the power state of connected equipment. A supplied system remote handset covers all the amplifier's functions, as well as Arcam Tuner, CD and BD players. This is easy to use and works flawlessly.
It generates a spacious soundstage, especially on good material, and reveals fine detail alongside surprisingly good depth. The sound it produces is very clear, has good air and sparkle, plus a touch of the delicacy normally only found in seriously high end amplifiers, one consequence being a solid, well-formed front-of-stage focus. The listener is invariably rewarded with a very good sense of scale, with fine bass grip, resolution and control, alongside excellent articulation of both male and female voices. A good sense of timing is maintained across the whole audio frequency band, allowing the rhythm and interplay between the musicians of a band to be revealed with ease, providing the source is good enough. It pulls the listener into the music in a way that very few integrated amplifiers can.
The micro dynamic structure is surprisingly good, as is the timing of interesting piano performances, and it also holds everything together well when playing loud. It also seemed indifferent to whatever load it was driving, and seemed just as happy with 4 or 8 Ohm loudspeakers.
Voice: 01223 203200