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AURALiC MERAK mono power amplifiers

AURALiC MERAK mono power amplifiers

Thus far, Hi-Fi+ has reviewed AURALiC’s TAURUS Mk II headphone amplifier/preamp (issue 105), VEGA Digital Audio Processor (issue 106), and TAURUS PRE balanced output, line-stage preamplifier/headphone amplifier (Issue 111). In this final instalment we take a careful look at the powerplants of the AURALiC family: namely, the MERAK hybrid class A/class D, 200W monoblock amplifiers.

The AURALiC MERAK came to our attention at the 2013 Munich High-End show, where they were used to drive YG Acoustics then-new Sonja 1.2 loudspeakers—speakers thought (perhaps with good reason) to be both demanding and somewhat finicky about associated amplification components. However, the MERAKs powered the Sonja 1.2s with obvious authority, ease, grace, and a welcome touch of sheer musicality.

The MERAK uses AURALiC’s distinctive ‘Hybrid Analog Amplify” technology—a circuit topology in which the front end of the amplifier uses the firm’s patented, signature ORFEO class A analogue amplification module to handle the voltage amplification workload, while the back end of the MERAK uses a low-impedance, high-speed switching amplifier module based on Hypex UcD (Universal class D) technology.  AURALiC’s concept, of course, has been to take a ‘best-of-two-worlds’ approach in hopes of giving the MERAK the speed, detail, smoothness, bandwidth, and linearity of a pure class A amplifier, but also the power, efficiency, dynamic agility, and low-frequency control of a fine class D amplifier.

There are already some strong industry precedents for this conceptually appealing design approach. For example, astute readers might note that AURALiC’s design strategy in several respects parallels the design thinking we have seen from the French firm Devialet with its own widely applied ADH (‘Analog Digital Hybrid’) technology.

 

Naturally, the quality of the ingredients used in the MERAKs greatly influences the amplifiers’ resulting sound quality. As we have mentioned in past reviews, AURALiC’s ORFEO class A module is a very special piece of amplification technology. The ORFEO module is patterned after both the circuit design and sound of the classic NEVE 8078 analogue recording console—a device renowned for its uncanny combination of clarity, transparency, and natural, unforced warmth. These qualities are very much in evidence in the MERAKs.  To improve performance further still, AURALiC isolates the MERAK’s ORFEO module inputs through a very high-quality, Lundahl-made transformer said to “reduce EMI by 100dB even under non-ideal situations.”

In turn, the Hypex UcD switching amplifier, which is the brainchild of the brilliant Belgian designer Bruno Putzeys, has long enjoyed a reputation as one of the finest class D amplification modules for use in serious, high-end audio applications.  Even so, AURALIC President and Chief Designer Xuanqian Wang was not content to use a standard, off-the-self Hypex UcD module in the MERAK. Instead, he developed a set of proprietary modifications for the module that together reduce high-order distortion components by greater than 10dB—a change Wang says provides, “a significant improvement in the listening experience.”

I wondered, as might some of you, why Wang opted not to use Hypex’s new NCore switching amplifier module in the MERAK, given that the NCore module is said to be even better than the UcD module. In a conversation on this topic, Wang explained that his decision was driven by two factors. First, Wang stated that with AURALiC’s proprietary modifications, the performance of the MERAK’s UcD module could draw “very close to even the best of NCore-based designs” –results made possible by AURALiC’s UcD modifications, but also by MERAKs’ overall deisgn. However, the second factor involved questions of build costs and ultimately of product value. At present, Hypex’s NCore module is dramatically more costly than the UcD module, so that had the MERAKs used the NCore module, the amplifiers’ selling prices would have more than doubled—a change Wang felt could not be justified.  As Wang put it, “We wanted to build an extremely high performance amplifier, but one whose price would also be accessible for a reasonably large number of music lovers.”

As with all of its other audio components, AURALiC has spent considerable time getting all the small details right in the MERAK. Thus, the amp uses a cabinet made of the firm’s proprietary, EMI-resistant AFN402 metal alloy with the chassis interior coated with a proprietary Alire Resonance Damper material that rejects EMI and damps mechanical vibration.  Further, the MERAK uses an uprated and expanded version of the firm’s ‘Purer Power’ Linear Power Solution, wherein incoming mains power is passed through a power purification module located upstream of a massive 500VA Plitron-made mains transformer. Downstream of that transformer, AURALiC provides a 56,000µF capacitor array capable of storing a stonking 120 Joules of energy (energy that enables the MERAK to deliver 16A of peak current for temporary output of up to 900W, into “large, power-hungry loudspeakers”).

 

The aesthetics of the MERAKs are understated and elegant, featuring gently sculpted, matte silver faceplates with tasteful, brushed silver chassis covers. Up front, one sees only a simple matte silver power switch and a small red pilot light. The rear panel is similarly clutter-free, sporting only a 3-pin balanced XLR input jack, a Cardas CE-type speaker cable binding post and the ubiquitous IEC-type power inlet connector. Apparent build quality, fit, and finish are very high, so that MERAK looks as if it should cost more than it actually does. As you will learn in a moment these initial, visual impressions of value and sophistication only grow stronger once you hear the MERAKs in action.

Before discussing the MERAKs’ sound, I would like to address two areas where biases might lead listeners to turn a blind eye or deaf ear toward strengths these amplifiers have on offer. First, let’s acknowledge that some readers suffer from what I call ‘FOW (Fear Of Watts) Syndrome’, meaning they expect powerful, high-output amplifiers to sound sluggish, muscle-bound, or veiled. Second, more than a few readers have been conditioned to think that switching amplifier technologies are—how shall I put this?—more or less the tools of Satan, or worse. If you happen to hold either of these beliefs, I beseech you to set them aside for the duration of this review. Yes, the MERAKs are indeed very powerful and, yes, they do incorporate switching amplifier technologies, but they are also agile, musical, and full of subtlety and nuance. My thought: If one simply treats the MERAK amplifiers as proverbial ‘black boxes’ (or in this instance, silver boxes) and listens with a wide-open mind, I believe one will find much to like.

Among the first and best things to like about the MERAKs would be the difficult-to-describe qualities of immediacy and vividness that they convey. These amplifiers are unusually agile and dynamically energetic so that on hard, sharp, fast-rising transient sounds, such as the percussion sounds captured on ‘Talking Wind’ from Marilyn Mazur’s Elixir [ECM] the MERAKs help the music to burst forth in a gripping, dramatic, and realistic way. Honestly, the transient sounds ‘feel’ so real that you might experience the urge to turn and look for musical instruments that of course aren’t actually present in your room.

This sense of vivid realism is only heightened when you listen to recordings that combine rich, vigourous transient information with multiple layers of subtle, subliminal, and yet pervasive spatial cues. A great example of this would be the track ‘Farrucas, for guitar’ from Pepe Romero’s Flamenco [Philips/K2HD edition], where Romero’s guitar provides masterful accompaniment for an also terrifically talented flamenco dancer. What’s both fascinating and downright breathtaking to hear are the very different ways in which Romero’s guitar and the dancer’s handclaps, toe taps, and heel stomps each energise the acoustics of the room.

 

Romero’s guitar has a fast, light, lithe, quicksilver-like quality, while the dancer’s handclaps activate the room in a very different way, in large part because their sound reverberates off both the walls and the ceiling of the recording space, conveying a realistic sense of height. The sharp, staccato toe taps and heel stomps, in turn, also activate the entire room, but add a new dimension to the mix: namely, floor interactions. A tremendous amount of very low frequency information gets unleashed on the more ferocious heel stomps, inviting listeners to imagine the (plainly hard-surfaced) floor shuddering under the dancer’s assault.

 What is impressive is not just the power and articulacy with which the MERAKs convey these disparate pieces of musical information—although both of those qualities are quite impressive—but also the deft and effortless way in which the amplifiers keep the harmonic and reverberant ‘signatures’ of each sound source separate, distinct, and true even in the midst of a very powerful and complicated mix. If ‘grace under fire’ is one measure of sonic excellence, then the MERAKs exhibit it in spades.

Similarly, listen to the explosive brass section swells heard in Clark Terry’s Chicago Sessions, 1995 – 1996 [Reference Recordings, HDCD]. These big-band horn section outbursts pose a special challenge in that they are not only loud and demanding, but also are rich in subtle and significant musical details (such as the distinctive attack and decay sounds of individual instruments within the horn section). 

Thus, the amp must simultaneously flex its dynamic muscles while maintaining the fleet-footedness and grace of a ballet dancer. Happily, the MERAKs rose to the occasion, delivering force and finesse in equal measure for a downright exuberant presentation.

Next, we need to consider the sonic benefits of the MERAKs very high power output capabilities (200W at 8 Ohms or 400W at 4 Ohms) and vast reservoirs of current drive (up to 16A for brief periods, for maximum peak output of up to 900W). These capabilities are not just desirable but necessary for those among us who wish to play dynamically challenging music on power hungry transducers (in my case, the very revealing but also very demanding Magnepan 3.7i loudspeakers).

As but one of many listening tests, I put on Thomas Newman’s soundtrack for the film American Beauty [Dreamworks] just to see how the MERAK/Magnepan combo would handle the soundtrack’s plunging and at times downright punishing low-frequency synth bass passages. The results were, in a word, spectacular, as the MERAKs firmly seized control of my Magnepan’s planar magnetic bass panels and forcefully compelled them to produce loud, low-pitched, yet very crisply defined bass (bass that I think would astonish those who think that planar dipole speakers ‘can’t handle the low stuff’).  The only problem I encountered, candidly, was that on one extremely loud and low passage the MERAK’s pushed the Maggies so hard that their bass panels temporarily bottomed out (I’m told this doesn’t actually hurt the speaker, but it can sound pretty scary should it occur). Even so, note that the speakers ran out of headroom while the amplifiers were still going strong. My point is that the MERAKs have sufficient clout to drive most any load you’d care to throw at them (and thanks, I think, to their extreme current drive capabilities, they actually sound more powerful than their specifications would lead you to expect). 

 

Thus far, we’ve talked solely about the amplifiers’ positive qualities. But, are there drawbacks to the MERAKs? I can think of only a few, though none of serious consequence in light of the amplifiers’ more than fair price. First, I wish the amplifiers offered both single-ended and balanced inputs, rather than balanced inputs only, since some preamps and preamp/DACs have single-ended outputs only. Second, I would like to see AURALiC reconsider its use of Cardas CE-type speaker binding posts. The Cardas posts sound great, but they are difficult to use, partly because they work only with speaker cables terminated with spade lugs, but also because they force users to hold both speaker leads (that is, the ‘+’ and ‘-‘ leads) in place with one hand while simultaneously tightening Cardas’ binding-post clamp with the other (and connecting dual sets of speaker leads is a daunting task). Finally, I would say the MERAKs narrowly miss achieving the very highest levels of sonic transparency, openness, high-frequency ‘air’, and ultimate refinement that certain more costly amplifiers might provide, though I’ve not yet heard anything at or even near the MERAKs’ modest price that can top them.

In summary, I think the MERAKs represent something of a price/performance breakthrough for those of us who seek top-tier (or at least upper tier) performance, but are not made of cubic money. I say this not because the MERAKs are ‘perfect’ amplifiers (there is no such thing), but because they are well and truly excellent amplifiers that normal mortals can, with a bit of judicious saving, actually afford to own. While it would be bad form for me ever to do such a thing, if I were to list some of the more costly amplifiers I have heard the MERAKs outperform, that list would include some very distinguished competitors indeed. That alone tells you how good these sensibly priced monoblocks truly are.

Technical Specifications

Type: Solid-state, hybrid class A/class D monoblock power amplifier.

Analogue input: One balanced input via 3-pin XLR connector

Analogue outputs: One Cardas-type speaker outlet.

Power output: [email protected] at 8 Ohms, 400W at 4 Ohms; peak current output, >16A (40ms)

Frequency response: 20Hz – 20kHz, ± 0.5dB

Input impedance: 10kOhm

Output impedance: Not Specified.

Noise: <50µV, 20 Hz – 20KHz, A weighted

Distortion: <0.01% THD, <0.01% IM, both from20Hz -20kHz at 1W

Dimensions (HxWxD): 70 x 330 x 330mm.

Weight: 8.5kg per amplifier

Price: £2,090, UK; $2,499, US

Manufacturer: AURALiC LIMITED

URL: www.auralic.com

UK Distributor: Audio Emotion Limited

URL: www.audioemotion.co.uk

Tel: +44(0)1333-425999

Tags: FEATURED

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