Arcam has gone through a few changes since its heyday in the eighties and nineties. Once an independent run by its founder and chief engineer John Dawson it is now owned by Canadian conglomerate Jam Industries and run by a dedicated managing director who leaves John to get on with the interesting stuff. He appears to have been having a lot of fun too, the A49 is by far and away the most ambitious and powerful amplifier that Arcam has ever made, it’s specified at 200 watts a channel which makes it one of the most biggest one box designs around. A far cry from the Alpha and FMJ models that preceded it, the A49 is a heavyweight with a price tag to match and uses an output stage class that is very unusual in serious audio.
It’s called class G and is a variation on class AB, the most popular approach with audio amplifiers. Class G combines a larger class A output than the first two or three Watts found with AB, in this case 50 Watts, and thus avoids the crossover distortion associated with that approach. A distortion that requires feedback to stop its effect being too obvious, this is one of the biggest reasons for the comparatively relaxed sound of class A designs. But class A produces so much heat that it is rarely used on amps with high power output. It is claimed that class G avoids crossover distortion by using multiple power supplies, a low power one for the first 50 watts and a secondary supply to provide the class B power above that. On paper it looks like an elegant solution to a problem that has beset amplifier designers for decades, so you have to wonder why no one else is doing it. Arcam’s Andy Moore suggests that this is because it is expensive, the mains transformer needs an extra secondary to drive the second PSU, and it’s complex, requiring critical PCB layout and a lot of R&D to get right. Class G as a topology was created in 1981 but the high speed silicon required to use it in the way that Arcam does has only become available in recent times. None of these reasons would stop other manufacturers using this approach however, maybe they are working on it right now, only time will tell.
Because the A49 is a class A for its first 50 Watts it runs pretty hot, those slots on the top of the case are not there for aesthetic reasons. To keep the polar bears happy there is the option to have it go into standby automatically when not used for a user specified amount of time. It has a good selection of in and outputs most of which are on RCA phono sockets, but there is an input and preamp outputs on balanced XLRs. The A49 is a balanced amplifier so these are not mere XLR connections as is often the case with relatively affordable kit. I’m surprised however that there aren’t more of them. There is also an MM phono stage that could be combined with a step-up transformer to use with moving coil cartridges. Two sets of speaker cable binding posts make bi-wiring straightforward and theoretically allow two sets of speakers altogether, it probably has enough power. Power is specified as 200 Watts in the literature but I’m told that in reality it’s more like 230 Watts into eight Ohms. This requires two linear power supplies that contribute significantly to the near 20 kilo mass of the A49. The preamp section has its own supply as you might hope and uses a Burr Brown volume control chip with 174 resistors onboard to minimise the degradation that attenuators tend to have on sound quality.
On the front panel the inputs have fixed names, which seems a little old school next to models where you can pick your own from the likes of Cambridge. Arcam has chosen a selection of names that reflect their AV knowledge base, so we have PVR, BD (Blu-ray) and SAT next to more conventional two-channel source names. You can program an input to have unity gain, ie bypass the volume control, for ease of integration into a home cinema or to use the A49 as a power amp. But given that Arcam makes the more affordable P49 power amp with the same guts, that doesn’t really make sense.
Balance of power
In the system driving the PMC fact.8 floorstanders the A49 sounds well controlled and revealing, it’s not quite as powerful as an ATC P1 power amp, or it doesn’t have the same degree of grip, but few amplifiers do, let alone integrated ones. What it does have is a good balance of transparency and power, it is particularly good at producing large scale imaging. The live cover version of ‘Billie Jean’ by The Civil Wars (Unplugged on VH1, Sensibility Music) for instance takes up the whole of the room’s width and height, the tonal richness of the voices and guitar standing clearly in the acoustic.
It’s not the fastest amplifier on the block, ZZ Top’s ‘Snappy Kakkie’ (Tejas, Warner Bros) is pretty robust but could have a bit more drive. However it’s easy to enjoy the timbre of Billy Gibbons’ fine axe work and the weight and dexterity of the rhythm section. Further listening lead me to the conclusion that the PMCs, which are nearly twice the amp’s price, might not be the best partner for the Arcam. So a pair of Bowers & Wilkins CM10 S2 floorstanders were brought in for a bit of contrast. These are reflex rather than transmission line loaded speakers and thus more representative of most models on the market. Their relatively rounded sound proved to work really nicely with the Arcam, the extra juiciness of the bass seemed to gel superbly. It is nearly always the way with amps and speakers and one suspects that this amp was developed with ported examples, maybe from the same company.
Low level detail was particularly well served here, it might seem insignificant but the quieter sounds are the ones that tell you about the acoustic character of voices and instruments, its’ where the magic lurks. Timing moved up a notch with this speaker and bass extension started to get really entertaining, not just in terms of depth but also in texture and shape. The sound overall is room filling with Felix Laband’s ‘Minka (And the Notes After)’ from Dark Days Exit (Compost), rich in detail and impossible not to enjoy. Patricia Barber’s ‘Company’ (Modern Cool, Premonition) has lots of low end weight yet stops and starts well. Power as we know is useless without control and this has both as well as a level of transparency that means there is plenty of difference between recordings. Acoustic pieces really benefit from this, you get to hear the harmonic subtleties and the different timbres of the various instruments with ease.
Image depth could have more variety but this isn’t something that many amps at the price can do, I have a piano piece by Javier Perianes (Manuel Blasco de Nebra’s ‘Piano Sonatas’ Harmonia Mundi) that is very revealing in this respect. The best amplifiers put the instrument in the next room, this shows the reverb on the instrument but not the full distance. Another piano, that of Keith Jarrett with his standards trio playing ‘Flying Part 1’ (Changes, ECM), reveals its magic thanks to the control, pace and finesse of the A49. The sheer brilliance of the playing and the inventiveness of the interplay between Jarrett and bassist Gary Peacock is a joy to behold, the piano sounds superb with real shine but no glare.
The nearest competition price wise that I had on hand for the Arcam A49 was the Leema Tucana II (£3,595), a smaller but similarly high mass integrated with a lower specified power rating of 150 Watts albeit one that nearly doubles into a halving of load (290W/4 Ohms). This has more grip and a stronger sense of pace in the context of a presentation that sounds coarse next to the A49. It does however have more get up and go, it provokes a greater emotional response despite its relative lack of sophistication. Going back to the A49 there is an increase in clarity and a decrease in leading edge grain, it’s a more refined beast for more refined music.
John Dawson is to be congratulated on the A49, by going out on a limb with a relatively new technology he has managed to produce the best amplifier of his career. The A49 is very revealing, powerful without edginess and impressively refined. It’s not the most exciting of amplifiers at the price but its quiet confidence keeps the speaker under control without getting in the way of the music. Those that appreciate the more sophisticated strains of musical the art will find it very enjoyable indeed.