Mark Levinson ML-50 Limited Edition Mono Amplifier Review
Craig Joyce auditions this exquisite high-end monoblock power amplifier package…
ML-50 Limited Edition Mono Amplifiers
In celebration of the company's recent fiftieth anniversary, Mark Levinson has introduced a new limited edition monoblock power amplifier, with only one hundred pieces available worldwide. The company claims that the ML-50 represents “the ultimate expression of power, precision, and purity”, no less. So can they meet the high expectations set by such a compelling description?
Employing monoblock amplifiers in a stereo system provides numerous advantages that should lead to improved audio performance. These benefits include enhanced channel separation, reduced potential for cross-channel interference, and the ability to deliver higher power output – thanks in no small part to a dedicated power transformer for each channel. This, in turn, results in improved dynamics and makes for a more accurate reproduction of complex musical passages.
No stranger to this form factor, the finely crafted chassis design of the ML-50 Limited Edition amplifier pays homage to many of the more iconic Mark Levinson amplifiers released throughout the company's extensive fifty-year history. Drawing inspiration from various models, the ML50 blends these distinct design elements to create a cohesive and visually striking product.
Taking a cue from the first-ever Mark Levinson amplifier, the ML-2, the name ML-50 is an affectionate nod to the brand's rich lineage. The front panel handles are reminiscent of the No.20 amplifier, representing a commitment to practicality and refined aesthetics. On the other hand, the vibration isolation foot design adheres to the general shape of the outrigger feet found in the No.33 and No.33H amplifiers, ensuring stability and minimising unwanted resonance for optimal performance. The product's look is refined and unobtrusive, with a pleasingly robust footprint. There's something of a stormtrooper feel to the styling, and I'm quite a fan!
The transparent glass top panel, replete with a backlit logo, is a design concept that the company had used in press photos for the No.53 amplifier, but this element never previously reached the production run. In the ML-50, this elegant top cover adds aesthetic appeal and serves a functional purpose, as it promotes efficient heat dissipation through convection cooling, ensuring optimal thermal management. The company's designers wanted to show off the internal beauty of the ML-50 and believed that the best way to do that was to make it visible:
As a car guy, I wanted to make it look like the glass covers you see on exotic sports cars like Lamborghinis and Ferraris where you see the beauty of the red valve covers and the intake manifold. Our mechanical engineering and industrial design team made it happen for us. Once we had the glass top sorted out, it only made sense to add drama to it by illuminating the internals with our signature colour via the custom red LED lights underneath the top cover.
Finally, the ML-50's heatsink design, characterised by triple-fin spacing, is also inherited from the No.536 amplifier. This design choice is also instrumental in effectively dissipating heat and helping to maintain the amplifier's longevity. With the ML-50 Limited Edition, the company appears intent to encapsulate half a century of amplifier design expertise in a single, stylish new product.
The ML-50's circuit design is based upon the award-winning No.536 amplifier but with new input circuits, increased capacitance, revised thermal parameters, increased Class A bias, and many other changes. It adheres to the Pure Path design philosophy, with no integrated circuits (ICs) or capacitors in the signal path. The company claims that this approach results in extremely low distortion levels and that its wide bandwidth ensures fast and detailed sound reproduction, while minimal negative feedback better captures musical subtleties. The amplifier sports a fully discrete signal path from input to output and is a direct-coupled design with no capacitors in the signal path.
Peering in the top cover, the well-laid-out design is dominated by huge custom-designed, low-noise toroidal transformers and high current linear power supplies built using low-noise, ultra-fast rectifiers and multiple paralleled filter capacitors. The amplifier comprises 12 bipolar output transistors and 12 bipolar driver transistors per output stage. Additionally, the power supply contains 8 rectifiers and 18 filter capacitors per output stage, providing a total of 169,200 microfarads of storage capacitance, according to the company.
As in the No.536 and No.534 amplifiers, the ML-50 primarily operates in Class A mode at low levels and transitions to Class AB at higher power levels. The company states that the ML-50 has a higher Class A bias compared to the No.536. This was confirmed with a touch test while the amplifiers were idling, as the fins feel warm, but not hot, to the touch. Rated at 425W into 8 ohms and 850W into a 4 ohm load, this is one serious power amplifier.
The ML-50 features Ethernet and RS232 control ports, allowing integration with third-party control systems. The former also provides access to a diagnostic webpage, which includes a fault log for the advanced protection circuitry and lets users modify settings related to standby power operation. When and how the amplifier enters standby mode can be determined, and users can view when the amplifier is clipping the signal. Three standby modes are available (normal, green and power save). Sadly, there is no functionality to allow for dimming of the internal lighting, which could prove problematic in some light-sensitive home theatre configurations. The USB port facilitates firmware updates, ensuring that the amplifier remains up-to-date with the latest features and improvements as they are published on the Mark Levinson website.
The rear of the ML-50 features two pairs of binding posts equipped with the company's proprietary Hurricane connectors. These custom-made, gold-plated, high-current loudspeaker binding posts are compatible with bare wire, spade, or banana plugs. The additional set of binding posts facilitates bi-wiring for compatible loudspeakers. The amp accommodates both XLR and RCA inputs, and an inconspicuous selection switch is located on the rear of the unit to specify the source type in use. 12V trigger inputs and outputs are provided to facilitate seamless integration with broader audio system components.
The ML-50 amplifier set comes with a pair of single-channel amplifiers and an accessory kit featuring two longish power cables, a gentle microfibre cloth for polishing, a pair of white gloves, and all the necessary owner's documents. To ensure safe delivery, the items are carefully arranged on a wooden pallet, encased in a sturdy three-layer cardboard sleeve, and secured with durable banding straps.
To assess the performance of the ML-50s in my system, I played hi-res audio from Qobuz using Roon. The audio signal was processed by my MSB Premier DAC and then played through a set of JBL K2 S9900 loudspeakers.
After completing the necessary burn-in period, it didn't take long to appreciate the remarkable performance of the ML-50 pairing. At lower listening volumes, these monoblocks produce a pleasing and natural sound, reminiscent of the rich tonality found in tube amplifiers. In particular, reverb tails are hauntingly beautiful, and acoustic instruments sound vivid and welcoming. However, when the volume is turned up, the ML-50s really come into their own, delivering a powerful low-frequency response that is so impressive. The amplifiers exhibit a remarkable level of dynamic control over the loudspeaker load, even when pushed to high volumes, resulting in no perceived distortion, sibilance, or unpleasantness.
At lower listening volumes, the purity of the ML-50 is clear to hear. Blackwater by David Sylvian offshoot Rain Tree Crow is a haunting and atmospheric track that immerses the listener in the song's hypnotic rhythms, ethereal vocals, and moody instrumentation. This amp presents the track with a dreamlike quality that evokes a sense of timelessness, letting it build to a crescendo, where the layers of sound can wash over the listener. Its tonality is both warm and inviting, offering an appealing window into the recorded acoustic that's positively tube-like – especially when compared to many Class D offerings.
Clark's Growls Garden proved an eye-opener through the ML-50. The ability of the amplifier to display such a deep clarity in imaging and separation of musical elements is excellent, taking a tightly mixed electronic track and allowing it to shift dynamically with ease, even with all manner of distorted effects and layers in place. As the volume is raised, this track becomes even more engaging, whereas with lesser alternatives, the sound can become aggressive and uncompromising. The low-frequency content is tight and supple, and the 15” woofers on my loudspeakers were clearly reaching deeply and with control to accurately present this track with such precision.
Telefon Tel Aviv's comeback single Lengthening Shadows is both a menacing and beautiful listen, with a dense soundfield carefully plotted by Joshua Eustis to be both enveloping and emotive. Through the ML-50, the sound stage is presented in a warm and engaging manner, with synthetic percussion ringing in the air while a liquid-like bassline locks the mix to the floor. In many systems, this track sounds confused and impenetrable, but this power amplifier repels this suggestion and gives a tangible insight into what this will have sounded like in the mastering studio.
Birmingham techno pioneer Regis's The Blind Departing is a masterclass in precision production and mixing. With such minimal content, stripped of any fat or flab, the Mark Levinson gets the opportunity to demonstrate a keen sense of space and the silence between musical elements in the mix. At lower listening volumes, this track is appealing, but as the level is ramped up, the grip that the amplifier has on the speakers is almost palpable. While my reference McIntosh MC1201 monoblocks offer a much higher power rating than the ML-50, it was hard to notice a difference in their performance, even at what many would consider insane listening levels.
Taking a well-recorded Jeff Buckley song like So Real and really pushing the ML-50, creates a unique listening experience. As the violence of the acoustic drums explodes in the room, the vocals materialise in front of you as if in an apparition. Having been fortunate enough to see the great man live in Melbourne in 1996, there was something of a flashback to be had as this song detonated in my living room. This amplifier demonstrates a willingness to dig deep and deliver distortion-free sound that is truly superlative.
Even playing middle-of-the-road produced indie rock through the ML-50 yielded very positive results. One of the more approachable tunes from Future Of The Left, The Hope That House Built opens with a simple guitar refrain before Andy Falkous's acerbic wit punctuates proceedings, then launches into his trademark screams and nonsense lyrics. Presenting this track in its raw form, this amplifier gave me what I wanted: an unadorned but accurate presentation that renders the mix warts and all, without trying to paper over the band's questionable production choices.
$50,000 for a pair of hi-fi power amplifiers is a lot of coin in anyone's language. However, with the ML-50, Mark Levinson has created a product that could be considered the pinnacle of any audiophile's dream system. Not only is it visually stunning – with cutting-edge technology infused into the design – but it also provides a future-proof path to building a cost-no-object, no-compromise system. It is hard to imagine a future loudspeaker investment that this amplifier could not adequately drive!
This magnificent pair of monoblocks produces a lovely, subtly warm tonality whilst still sounding crystal clear. It is capable of handling massive dynamic shifts without compromising its panoramic soundstage. Even when pushed to the limit, it shows immense grace under pressure. Neutral yet detailed enough to handle any genre of music – be it acoustic, indie rock, or intricately arranged electronica – the ML-50 behaves absolutely unerringly, like a true high-end product should.
With an engineering degree in digital signal processing and a storied career in IT networking and cyber security, Craig loves to push the boundaries of audio technologies. An aficionado of live music with personal detours in music production and event promotion, Craig is a long time enthusiast of post punk, electronic and experimental music.
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