Luxman L550 AX Mk-II: Class A amplifiers are not as popular as they used to be. Nowadays, push-pull or digital amplifiers are becoming more advanced and efficient, making them better for the environment and more versatile. However, some people still believe that Class A amps, which operate without crossover distortion, might sound better. Recently, when testing the INT 25 pass and the Luxman L-550AX-II at amp reviews, it seemed like Class A amps still have an edge in sound quality.
Luxman’s L-530, L-550, and L-560 amplifiers have been on my wishlist for over forty years. It seems I’m not alone, as these iconic Class A amps are highly sought after and expensive on the used market. Luckily, Luxman still offers Class A amplifiers, including the L-550AX-II, which is priced at 6,450 euros. During testing, it proved to be impressive, with a touch of nostalgia for the 1980s.
Let’s start with the impressive build of the “small” L-550 AX-II: right out of the box, you’re met
with a hefty weight of 24.3 kilos that needs to be carefully balanced. Luxman’s craftsmanship shines through, reminiscent of renowned brands like Yamaha or Accuphase: smooth edges, impeccable fit,
and a satisfying click of the relays throughout the device. It’s exactly what you’d expect from a top-notch amplifier.
As for its features, the L-550 AX-II takes a pleasingly classic approach. It includes REC-In/Out, preamp output, and power amp input, along with five high-level inputs (including a balanced XLR input) and a built-in phono stage accessible at the back.
The discrete phono board, located behind the connection sockets, offers switchable gains for MM and MC pickups. While there are no adjustable settings, Luxman’s design incorporates average resistances or capacitances, which proves to be more than satisfactory. Testing with both the pre-installed ATR SPU (MC) and the Ortofon 2M Black (MM), the sound was magnificent, retaining the characteristics of each pickup. With the L-550 AX-II, there’s no need to invest in an additional phono stage in the sub-700 euro
range you’re getting top-notch performance right out of the box.
The Luxman L-550 AX-II operates as a transistor amplifier with Class A circuitry, effectively eliminating typical takeover distortions. However, the power output within this low-distortion range is
relatively modest: 20 watts into 8 ohms or 40 watts into 4 ohms. These specifications are notably conservative, according to Luxman’s measurements.
In previous tests conducted by Stereoplay, the predecessor model exhibited slightly higher power
output, but this variance doesn’t significantly impact performance.
Despite its old-fashioned design, the L-550 AX-II incorporates several modern features, including
the innovative volume control system called LECUA (Luxman Electric Controlled Ultimate Attenuator).
This system utilizes a processor to enable precise volume adjustments across 88 steps, offering
enhanced control and reduced noise compared to its predecessor. While some may question the impact of a volume control system on sound quality, the LECUA1000 proves its worth.
Those familiar with passive preamps, which solely rely on a volume control, understand the potential
for significant improvements in sound quality with such advancements.
Despite efforts to identify significant differences from its predecessor, the Luxman L-550 AX-II doesn’t appear to undergo many noticeable changes. Internal inspection reveals no alterations, and technical data doesn’t provide much insight either. However, a few noteworthy updates include borrowing the
power amplifier modules from the larger L-590AX-II, refining the sophisticated negative feedback,
and a slight increase in the damping factor from 160 to 200. While these modifications may seem minimal, their impact on sound quality is substantial.
According to Krey Baumgartl, a sales representative from the sales department (IAD), the external appearance may not be particularly impressive, but the L-550 AX-II represents a significant
advancement in sound compared to its predecessor. This sentiment aligns with Luxman’s commitment to prioritizing sound quality over cosmetic enhancements.
Indeed, the subjective experience confirms this assessment. In comparison to the L-550 AX tested in 2014, the current AX-II model delivers a wonderfully full-bodied sound, demonstrating Luxman’s dedication
to continuous improvement and audio excellence.
Build L550 AX Mk-II class A amplifier
When it comes to this type of amplifier, I don’t expect cutting-edge technology. Instead, I anticipate a familiar structure and features reminiscent of the past. In addition to the aforementioned inputs and outputs, this includes classic elements like the characteristic VU meter, a headphone output, tone controls, and a loudness curve. Additionally, there are thoughtful touches such as the ability to switch to mono and the option to bypass all tone controls with the “Line – Straight” button.
One notable aspect is the front panel of the Luxman L-550 AX-II, which is adorned with control switches and buttons. However, some functions can only be activated using the supplied remote control, such as the mono or loudness function. This blend of traditional controls and modern remote functionality
adds convenience and flexibility to the amplifier’s operation, catering to both nostalgic and
contemporary preferences alike.
As a classic Class A amplifier, the L-550 AX-II tends to generate more heat compared to its AB counterparts. This is due to its relatively high power consumption, even when idle, consuming around 170 watts when not in standby mode. From an ecological standpoint, this high power consumption raises concerns, although it’s worth noting that such amplifiers, like its renowned predecessors, are built to last and rarely end up in landfills—an important consideration for sustainability.
Given its tendency to generate heat, it’s advisable not to place the Luxman L-550 AX-II in narrow cabinets or racks without adequate ventilation. It requires some breathing room to dissipate heat effectively.
Moreover, the choice of speakers is crucial to maximize the amplifier’s performance. While it offers a preamp output for connecting to more powerful power amps, it’s generally not recommended due to compatibility issues. Instead, pairing the L-550 AX-II with high-efficiency speakers such as Blumenhofer or Spatial Europe models yields optimal results. Alternatively, it also shines when paired with smaller, fine-quality speakers like the Dynaudio Heritage Special, B&W 805 D4, or the high-efficiency Stenheim TWO, delivering stunningly good sound in smaller listening environments.
In cases where the amplifier’s performance limit is exceeded, it doesn’t exhibit harsh or unpleasant qualities. Rather, it gracefully rounds off the edges, maintaining its transparent sound image albeit with a slight loss of clarity at higher volumes.
Hearing Test Luxman L550 AX Mk-II class A amplifier
The Luxman L-550 AX-II presents a slightly slower pace compared to classic transistor models like the Neukomm CPA 155S, yet it delivers an outstandingly good integrated amplifier experience. The Neukomm deserves credit for its robust and crisp performance, particularly in the bass range, as well as its superior coarse dynamics and maximum level output.
It may take a moment to adjust to the Luxman’s leisurely pace, but once accustomed, its exceptional qualities become apparent. The timbre, fine dynamics, grace, and authenticity it brings to recordings are simply extraordinary.
For instance, in Rimsky-Korsakov’s Scheherazade, the opening notes of “The Story Of The Calendar Prince” feature a lovely yet slightly plaintive violin tone. Switching between the Luxman and Neukomm amplifiers during this passage reveals that the L-550 AX-II extracts even more power and warmth from the violin tone, along with a wealth of micro-information, resulting in a sound that feels remarkably real.
We also compared the Luxman with other integrated amplifiers from our reference shelf, including the extremely powerful Atoll IN 400 ES and the tube amplifier Fezz Audio Lybra, equipped with a double 300B configuration achieving around 20 watts per channel.
In ideal conditions—like being in a smaller room and sitting closer to the speakers—the Fezz Audio Lybra amplifier came closest to matching the Luxman L-550 AX-II in terms of sound. The Lybra, being a tube amplifier, also had a natural sound with a touch of airiness, although it didn’t quite have the same depth as the Luxman.
A few weeks ago, there was much excitement about the INT 25 pass amplifier, which also operates in Class A. Although I couldn’t directly compare it with the Luxman, it seemed like the INT 25 pass had a bit more power and dynamics when paired with the Dynaudio Heritage Special speakers.
However, this doesn’t take away from the exceptional performance of the Luxman L-550 AX-II. Thanks to a recommendation from ampreviews sound engineer, I discovered the album “Book Of Romance And Dust” by Exit North. Despite its melancholic tone, the jazz music on the album was received exceptionally well, revealing intricate details that were captivating. Singer Thomas Feiner’s voice, especially when paired with the Luxman amplifier, was incredibly powerful.
Even though I rarely listened to “Book Of Romance And Dust,” the combination of the Luxman amplifier and B&W 805 D4 speakers compelled me to do so. The sound was so captivating, natural, and beautiful that I couldn’t resist. Overall, it was a wonderful experience that I’ll never forget
Conclusion Luxman L550 AX Mk-II class A amplifier
The Luxman L550 AX Mk-II, a “small” Class A integrated amplifier, delivers precisely what you’d anticipate from it: a flawless execution of the distinctive Japanese hi-fi approach. With meticulous attention to detail, flawless mechanics, and premium materials, Luxman has crafted a product that delights the heart. It combines an array of features with an incredibly rich sound.
In a previous review of the Pass-INT 25, colleague Bernhard Rietschel remarked, “If you have the budget and inclination for a class A amplifier, the Pass INT-25 is the best integrated amplifier you can get.” The same sentiment applies to the L-550 AX-II, albeit at a slightly lower price point. Compared to the more dynamic yet pricier Pass amplifier, the Luxman offers a comprehensive range of features that will appeal to many music enthusiasts.
It’s important for potential buyers to understand that a class A amplifier won’t deliver earth-shattering volume levels. However, in return, it offers a wonderfully pure tone that is seldom encountered elsewhere. Thus, for those who prioritize sonic purity and appreciate meticulous craftsmanship, the Luxman L-550 AX-II is a standout choice in the world of integrated amplifiers.