A, B, C, D, G? The alphabet is different. A melody? Ok, in the notation of the rest of the world B writes yes instead of H as we Europeans, but also the pattern, A - H - C - D - G is quite pointlessly. A scale is it not, interval or chord not really. No, it is the enumeration of amplifier classifications.
The first, built with tubes amplifier ran in the Class-A operation. Class-A amplifiers consume a lot of energy and produce tons of waste heat, but work very linear, ie distortion - at least as long as the tubes or transistors used are used in their "comfort zone". With the separation of the music signal into two half-waves Class-B was possible, while you still maintains a more or less pronounced Class A share in audio circuits to obtain the so-called crossover distortion in the handle. To date, most hi-fi amplifiers work in class AB operation, which is more efficient than pure Class-A and distortion poorer than a pure Class B amplification. Class C is very efficient for hi-fi amplifier but not relevant, because you do not get here the distortions in a usable for audio playback level (high-frequency technology is a field of application). The extremely efficient Class-D, the so-called pulse width modulation was long as not hi-fi standards. That has changed radically in recent years, but so entirely uncontroversial, these amplifiers are still not. And now comes with Arcam same class-G. If it does not Arcam (Web: www.arcam.de) would - I would dismiss it as a marketing ploy.
The equipment of the FMJ series (FMJ stands for "Faithfull Musical Joy") it is customary for Arcam addition to various other product lines "classic" hi-fi products. The amplifier usually called simply "A" followed by a number. The first product Founded in 1976, A & R Cambridge, for the acronym stands ARCAM was the amplifier A60. On the new Class G circuit technology but one is obviously so proud that the "G" has been included in the model name. Therefore, our candidate is now called FMJ A39 G. Also new is the larger model FMJ A49 G. But what is behind the G-Class?
Look at the output transistors of the Arcam
Well, in principle, a conventional Class AB design that is almost reached by a trick the efficiency of a Class D amplifier. The trick is that the used AB amplifier is designed for high performance, but usually runs with a low supply voltage. This saves energy and causes very little heat. However, the amplifier would in terms of performance to its limits. Therefore, a Class G amplifier has a kind of turbo power supply - a second power rail with integrated switching technique. When more power is requested is changed to the higher operating voltage, and the amplifier can provide its full power. If the service is no longer needed, the amplifier will return to the low level of energy and waste heat. The trick is that this circuit must be very fast to avoid a "turbo-lag" is created, the amplifier so immediately and without delay delivers power when needed. This is possible with the latest, extremely fast switches, so the manufacturer. Arcam have been collected using this technique already in the AV receivers 600 and 750 experience before being used now in hi-fi amplifiers.
While it probably mainly comes at the AV receivers in the narrow and crowded, which usually prevails in such devices to minimize the space required for heat sink might be the reason to use the Class G technology in the new stereo amplifiers, be different. About all devices in the consumer electronics floats the sword of Damocles of the EU Ecodesign Directive. And even if that has not yielded binding guideline for the allowed energy consumption of audio amplifiers, is anticipated with regard to other product ranges that everything here will result in a self-regulatory mechanism. Will say: It requires producers to develop and implement energy-saving technologies and explains the respective technically feasible for the measure of all things. So you have to write any concrete figures into law that are outdated at some point. In audio amplifiers, it looks as if Class D is set standards. Anthony Michaelson of Musical Fidelity has already been set for this reason the production of its Class A amplifier. Since it is very wise of Arcam, set equal to an energy-saving technology in the new amps.
Back to the Arcam FMJ A39 G. On the back of the unit, there are seven inputs including a phono MM input. The leaves of the way to reprogram also to the line input if you still prefer to rely on an external phono equalizer / preamp or wish to join another high-level source.
There are also individually switchable outputs for two pairs of speakers or bi-wiring operation of a pair of speakers, a preamp for bi-amping or when otherwise you just need a few regulated output (about to drive a subwoofer), a Rec Out output and even a USB-A port. However, assumes no music data in digital form opposite - a built-in DAC does not have the G A39, then it would probably also a USB-B connector. If necessary, update the software of the Arcam can be made here, however.
However, the USB-A port can also be used to power a mobile feeding device, such as a tablet PC or a smartphone, used. Fittingly, it is on the front of an eighth input in the form of a 3.5 mm stereo jack, so you can forward about connecting the smartphone as a player. In addition, there is a second 3.5 mm jack for connecting headphones.
If the Arcam is prepared for software updates, there's also a microprocessor-controlled operation. The enables all functions easily from push button to operate - both using the included remote control, which also serves as a remote control system for other Arcam devices, as well as on the front panel. Here the volume is then controlled via an authentically designed as a knob encoder. About the currently selected input as well as the volume eigestellte informed in a bright green sympathetic dot matrix display, which even with a few other settings, such as at the balance indicates the need to know and be dimmed or deactivate. Something missing? Ok, balanced connections there are only at the larger model Arcam FMJ A49 G.
The Arcam FMJ A39 G from above
I am impressed by the build quality of the Arcam. Although it looks like all units of the FMJ series plain, upon closer inspection, it is found, however, that behind everything else to it than thrift. So its slightly curved front is just not simply a curved piece of aluminum sheet, but is apparent from its own strand profile or was milled into shape, because their material strength decreases upward from. And that the front is not even a centimeter thick, I think understatement. For a look inside shows not least an impressively large toroidal transformer. So off saving rolls. Two cooling fans located inside the Arcam the uprising against them heatsink contrary. This is significant. Why should I install immense heat sink when the amplifier works most of the time anyway over low heat thanks to class-G? And if things start to heat go forth prevail guaranteed volumes, with which one so small fan eh no longer hear.
Two fans guarantee just in case for fresh air