Arcam A85 amplifier
Integrated amp marks completely fresh start

Readers will already be familiar with the new Arcam DiVA (Digitally integrated Video & Audio) range, which is fast replacing the venerable Alphas. We looked at two of the new models, the DV88 DVD-Video player and AVR100 home-cinema multi-channel amplifier last month, and here we take the wraps off another, the A85 integrated amplifier. This is a particularly important introduction, as Arcam was launched with an amplifier, the A60, and amplifiers made the company’s reputation.

Some of the DiVA models are based on existing designs, either Alpha or FMJ models, which themselves date their ancestry to prior Alpha designs. The DV88 and AVR100 of course are new and unrelated to anything Arcam had produced before, and they show how Arcam is expanding its range to match its new broader ambitions. The DiVA A85, however, is quite different. It is the first design from Jonny Reckless, not a pop star but the new engineering manager at Arcam, who on this form is one to be watched.

So what kind of amplifier is the A85? Well, it would be unfair to say that it is completely unprecedented in the Arcam range. It clearly draws on the thinking, if not the hardware, that first saw the light of day in the Alpha 10 amplifier, the first Alpha product to be based around a software engine that provided value-added facilities and flexibility. The A85 extends the same theme. Switched on from cold, the amplifier shows a welcome message in its large green dot-matrix display. The message can be user-programmed: Arcam decided to make mine say ‘Hello Alvin’, which is the first time I have been addressed in the first person by an electronic gadget.

The A85 is very much software-driven, to an extent that puts the Alpha 10 in the shade. Using the remote control or dedicated enter and select keys on the front panel along with the multi-function rotary that normally acts as a volume control, the whole personality of the amplifier can be changed.

A default volume level can be set, and inputs normalised so that there are no sharp volume steps when changing inputs. Balance can be adjusted in the same way, and remembered for each input, as can bass and treble settings, which can be set either globally or for each input. The volume control has three levels of operation: standard, fine (meant for low level listening) and reference (which works in fine 0.5dB increments), and the display will show either a volume graphic or a numeric readout scaled in decibels. In addition, the welcome message can be programmed as described earlier, the auxiliary input label can be changed to phono when the optional phono step-up is installed, or all settings can be returned to their factory defaults.

The A85 has seven line inputs as standard, two of which are tape circuits, with tape-to-tape dubbing and tape monitor facilities, and it is possible to set the record feed independently of the source fed to the speakers. Indeed, a wide range of system configurations is possible. A headphone socket is fitted, and so are connections for two pairs of speakers which are relay-switched independently by controls on the front panel, the relays placed adjacent to the rear-panel sockets, and within the output stage feedback loop.

It’s also possible to unhook the pre and power amplifiers and use them separately, typically with a P85 two-channel power amplifier for biamplified systems, or with a P85/3 three-channel system as part of a home cinema or multi-channel audio system. An add-on module is being developed for the latter application. Unusually for a mainstream integrated amplifier, trigger in and outputs are provided for multiroom systems, or to switch the mains power on any P85 or other trigger-equipped Arcam component. Finally, the remote control is a full function design that will also operate an Arcam analogue or DAB tuner and a CD player.

As important as what it does is the manner in which it does it, and this is the real story of this amplifier. After all, any idiot can design an amplifier with lots of toys, and many have done so, but the results are often disappointing; hence the continued interest in minimalist circuit layouts for the audiophile market. This amplifier marks a complete break in the Arcam amplifier design tradition. Out go Arcam’s favoured MOSFETs in favour of high-speed bipolar output devices with onboard temperature compensation, with current feedback and a full DC coupling, separately implemented in the preamp and the power amp. No capacitors appear in the signal path.

The control system is also new, and along with the display board has its own separate regulated power supply, as well as being physically separated from the rest of the board. At rest, with no control signals being transmitted, all digital clocks are turned off, and the circuit topology relies on properly terminated and decoupled slow serial links, with no fast leading edges of the kind that could interfere with the audio being injected into any circuit. When the display is turned off drive circuits are also disabled to kill electromagnetic interference.

Even the tone controls are unusual. When no boost or cut is selected, the amplifier recognises the fact, and bypasses the whole stage. When it is used, the response shape is quite different to the usual Baxandall type circuits, which provide at best a shelf lift at the frequency extremes. In this case the circuits simulates an LCR circuit, and provides a bell curve, with maximum bass boost around 80Hz, and negligible boost at 20Hz or below, to avoid wasting power and loudspeaker cone excursion. In effect it works as a fixed-centre frequency parametric equaliser.

The volume control is also based on a completely new dedicated audio device. This design was originally intended for home cinema use to the THX Ultra standard, and offers 128dB of gain in 0.5dB steps, 72dB of which is allocated to the volume control, the rest being used for the input normalisation and balance features. Finally, the balance control here is of a constant power type, applying 3dB of gain to the favoured channel when the other one is minimised.

I have now had access to two samples of the A85 over the region of 8-10 weeks, and during that time it has rarely been out of use. With the hardware that is available to me as a result of ongoing projects, this amounts to a real compliment. It is also something of a surprise. Why? Because it simply doesn’t sound like an Arcam amplifier. The Alphas generally received good notices over the years, and for mainstream application they have been at least satisfactory on the whole, but they have not been the kind of amplifiers to get excited about. The A85 is a much sharper tool.

There is none of the familiar sogginess or give in the sound of this amplifier. It is altogether leaner and more detailed in balance; the bass is well extended and hard hitting, but it is not excessively warm. Some might think it dry, and certainly the A85 doesn’t sound ‘big’, unlike some super-amps. Noise levels are negligible, distortion is subjectively low, and bandwidth (controlled by a passive filter at the input) is wide — or at least that’s how it sounds.

The whole effect is one of greater transparency and detail, and a much closer approach to the source, and this was apparent with all of the source material (some from SACD, but most of it from CD) I had available, from Bach (Violin Concertos with the Cologne Chamber Orchestra on Naxos) to Bartok (Concerto for Orchestra with the Budapest Festival Orchestra/Ivdn Fischer on Philips), and including choral and unaccompanied voice. But the A85 does nothing to disguise limitations in source material, and while some SACD titles sounded glorious, this was far from the case with some equivalent DVD-Audio material, including the recently issued Barenboim Beethoven symphonies, during the limited time I had a DVD-Audio player available.

It was clear talking to the designer that the technology incorporated into the A85 is scaleable, and speaking personally I can’t wait to hear the next amplifier to benefit from it. In the meantime, remember the name of the A85, and buy one today. It’s a knockout: not only the most exciting amp introduction I’ve heard for some time but, even better, it doesn’t cost a fortune.