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Our full review of the Brax Matrix MX4 is below, but you can read the original pages and this entire issue of AUSTRALIAN INCAR free by clicking the image above.


Many moons ago I read an article stating that amplifiers have zero bearing on sound quality, and that speakers alone were to be the source of primary concern. I remember at the time thinking that this sounded a little insanus cogitandi — and thankfully nowadays many know better. Though not everyone, as those in the business of selling high-end amplifiers will tell you.

Yet really, it’s the speakers that are the intrinsically ‘dumb’ devices, for lack of a better term. They sit prone, doing absolutely nothing until they’re instructed what to do, and while of course speaker design and quality play a very important role in the reproduction of quality sound, it’s the amplifier that tells the speakers in which linear direction to move, how far — and, most importantly, how accurately.

Astute audio designer Brax understands this, and understands it well. A child of parent conglomerate Audiotec-Fischer, Brax was conceived by Heinz, Gudrun and Julian Fischer in 1990 and henceforth has grown from modest beginnings as a niche supplier to now servicing more than 50 countries across the globe from its headquarters in Schmallenberg, Germany. Successfully building a reputation as an innovative, no-compromise audio manufacturer is no small task, but then it only takes one audition of Brax equipment to get the message — it’s no fluke that the company has gained its reputation. Should you remain sceptical then grab a cup of tea and take a seat, while I put one of the marque’s most intimidating behemoths to the test.

Given the company’s comparatively small size, Brax presents a modestly-sized amplifier stable, with only two ranges — the Graphix and Matrix — each containing a single two-channel and single four-channel unit. Though the two sets actually share remarkably similar ancillary specifications, the Matrix units are far larger, and when I say large… dust down your
thesauri, people, because words like ‘gargantuan’ don’t begin to do these things justice. They’re quite simply colossal, in every sense of the word.

The MX4 sitting before me, for example — it’s capable of powering an apartment block. The product of endless hours of research and development, this amplifier brings together the latest in material evolution, technical advancements and meticulous manufacturing processes, implemented to exacting tolerances for an end result which is nothing short of astounding.

Before I get too frothed at the mouth, however, let’s start with a little background. In a day and age where many an amplifier manufacturer rushes into making everything ‘digital’ in order to go smaller despite this being often to the detriment of sound quality, Brax instead put aside this temptation and stipulated from the start that the Matrix units must remain Class AB. While Class-D units are more electrically and thermally more efficient, and can boast a smaller footprint, they just don’t share the same quality of sound. We could debate in long form whether this be due to Class-D building up waveforms from digital square steps, or from its inherent inaccuracies rising with frequency, or from delivering non-linearity at low levels. No matter the reason — Class AB inhabits more solid ground, tried and tested within the analogue realm. Its reputation for accurate audiophile sound — when expertly applied — is well established.

Since Class-AB generates more heat, it’s harder to cater for higher power ratings, so it is quite the statement to say that the MX4 is a four-channel design with each channel outputting just over 275 watts continuous when presented with a four-ohm load. And the unit is bridgeable, returning you just over 550 watts per channel pairing. Its outputs are carefully monitored and regulated to ensure optimal control, ergo loading it down excessively won’t send its power output figures flailing about wildly, as can be the case with many other amplifiers.

As if the power figures aren’t jaw dropping enough, wait until you get a load of the accompanying specs. How does total harmonic distortion of 0.001% grab you? (Insert eye-popping emoji here.) A damping factory of over 1000 indicates complete domination over undesired cone movement and controlled deceleration too (if you’re wondering whether that’s impressive, note it’s widely agreed that humans cannot discern differences much beyond 50). Reciprocal speed and accuracy is maintained thanks to its incredible slew rate of 20V/µs; separation of 80dB ensures minimal channel bleed, something often overlooked by serious audiophiles despite them shelling out on high-end processors, to get the staging and imaging perfect. Noise and artefacts are also kept inaudible given an impressive signal-to-noise ratio of 110dB. Last but not least is its frequency response — from 10Hz at the bottom through to, um, 80kHz, so it’s good to know that besides its core market of humanoids, the Brax will be able to entertain everything from fruit bats to sperm whales… assuming you can fit them in the car once you’ve found room for the MX4.

With the performance specifications canvassed, let us now move to the physical build and the innovative technologies encompassed within. I carefully removed the bottom plate with trembling hands — I’d seen images of the fastidiously-designed internals, but nothing quite prepares you for the gorgeous topology lurking within (see the glimpse left). If ever a picture summed up amplifier circuitry perfection, this is it.

Not only are these handmade wonders packed to the hilt with some of the tightest tolerance components money can buy, they also boast some of the most advanced technology hitherto available. Featuring two separate power supplies each dedicated to its own pair of channels, the electrical odyssey starts out with no less than eight 5000µF/18V capacitors which serve to stiffen and smooth the incoming voltage before it’s shunted into twin titanic toroid-core transformers plus two storage chokes, to be stepped up to the final voltage. Additional stability can also be garnered via a separate terminal which allows for the plumbing in of a Brax power stabiliser if you so desire. Speaking of the transformers, it’s worth mentioning that these have been specially developed, employing highly-efficient core materials in order to guarantee over 1800 watts to be made available for distribution to the power caps.

So far as power storage is concerned, Brax has seen fit to include no fewer than eight 3300µF/100V power capacitors (total capacity 26,400µF, thanks very much), ample for handling any impulse load presented to the power supply. And with such enormous power on tap, delivery is equally stupendous, with twelve 200-ampere high-grade transistors in addition to 32 hand-selected high-end MOSFETs clamped in arrays below the lateral circuit boards. This is not just haphazardly set in motion, either — the amplifier and power supply are processor controlled, ensuring everything stays operating within predetermined parameters.

In its search for that extraordinarily low-noise performance, Brax has omitted signal manipulators altogether, aside from the gain controls. There’s no crossover controls, no phase control, no bass boost — nothing. Just raw clean power. This is a phenomenon not uncommon when talking serious high-end amplification whether it be in the car or the home — if you need signal processing, do it elsewhere; the amplifier amplifies, and only amplifies (remember Stewart Hegeman’s definition of an amplifier: ‘a straight wire with gain’). To further highlight the absolute sound perspective, the MX4 features a BurrBrown 24-bit DA converter behind its twin Toslink optical digital inputs, so it can accept a fully processed digital signal from the Brax processor, upon which point it can perform the conversion to analogue in-house.

Not only could it, as mentioned, power an apartment block, it slightly resembles one too. At 11.5kg it’s a physically imposing affair, with an outer case measuring 360mm square with a height of 79mm. This is constructed from high-grade aluminium, presented either in a raw brushed silver or black anodised finish depending on your preference. The Brax logo, Matrix logo and serial number are all photo-etched onto a metallic plaque which is sunk into the top face and centred. Along one end are gold-plated power, earth and remote terminal blocks able to accommodate up to 0AWG cable, while at the opposite end reside the inputs, gain potentiometers and speaker output terminals capable of accepting up to 8AWG. The amplifier comes presented in a beautiful timber case, and Brax also includes a signed birth certificate (in addition to a t-shirt).

With trusty test instruments at the ready I installed the MX4 and set the gains, a straightforward task given they remained all the way down — you surely won’t need to raise this amplifier’s sensitivity, such is the enormity of its ability. For the sake of testing I did raise them while playing my zero-noise track, and not surprisingly it’s near completely noiseless until you literally hit full gain, and even then it’s insignificant in real-world listening terms.

Winding things back to commence with the actual sinusoidal music the MX4’s performance
was downright awe-inspiring — and I don’t mean simply blowing-your-hair-around impressive (though it’s capable of doing such, and flapping your trouser legs too). No, I refer to its aural minutiae, the way it presents tiny nuances and idiosyncrasies in the sound; this is nothing short of incredible. It simply misses no detail. Whether I was listening to softer classical and jazz or harder metal and techno, the MX4 presented detail after detail, including some I’d never noticed before. When playing the sub-bass and mid-bass instruments — the likes of pipe organ, cello and tuba through to bass guitar and digital bass drops — the sound was powerful but smooth and natural. When playing mids through to the higher treble notes, there were none of those pitches where many big amplifiers send you scrambling for cover; rather the MX4 was simply exquisite. Higher notes are presented superbly, terrifically controlled, completely devoid of any harsh peaks in the linearity. I was enjoying this through suitably high-end speakers, yes, but the reality is that the MX4 will bring the best out of any given speaker complement, while given a high quality source and high quality speakers, the ensuing atmosphere it creates borders on the indescribable, almost the unimaginable.

When designing the Matrix amplifiers, Brax possessed clear-cut aspirations to develop a benchmark amplifier by which all others would be measured. Difficult though the task may have been, it’s succeeded, and delivered an inestimably rare result of true reference quality. We’re aware that finding a Matrix amplifier to audition may prove a little challenging, but if you are presented the opportunity, jump at it. There are very few audio components capable of offering a belief-busting epiphany of an aural experience. Without any word of exaggeration, the MX4 provides just that.

Price: $5999

+ Stunning build
+ Stunning sound
+ Stunning everything

– You pay a price for stunningness

TYPE: Class AB four-channel amplifier
POWER RATING: 4 x 275 watts continuous at four ohm
FEATURES: Raw power

Contact: Audiotec Fischer