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But it isn't a perfect amplifier and has its own clearly defined character that must be taken into account while composing a system around it. Its timbre is light rather than saturated. This might seem surprising to those raised on the legend of the Musical Fidelity A1 amplifier with its thick warm Cretian summer sound and rather meager dynamics. That isn't class A. Or rather, it's one of the possibilities of that class that doesn't show its most important traits of resolution, transparency, lack of coloration and dynamics. A sound similar to the Musical Fidelity can be found in the A-30 Accuphase while the A-45 and A-60 models are completely different and timbrally closer to the Luxman. Placing the L-550A II in a transparent system will occasionally have us miss the midrange saturation below the treble. This is not a brightening per se but an emphasis of energy relative to the band below it. This is why you need something capable of the splendid dynamics and (almost) unbeatable resolution of this amplifier which simultaneously is capable of adding a bit of body. You might go about this by adding transparent loudspeakers like the Harpia Acoustics Marcus or something from the Monitor Audio Gold series with a rather warm player that won't obscure anything. This could for example be the Recall Trigon (a Mk II version has since become available) or Prologue Eight Prima Luna, or -- this would be a phenomenal combination -- the small Luxman D-N100 player. While apparently somewhat toy like, this last one will surprise many music lovers. A good choice could also be the Japanese TRV-4SE TRI. Then add cables like Supra and done you are. You could also pursue a different path by combining a cooler source and warmer loudspeakers like the A.R.T Loudspeakers Stiletto 6 or something from Dynaudio or Harbeth.

We should always obtain a very thorough dynamic sound with splendid rhythm and coherence. The lowest bass will not be especially forceful nor the soundstage particularly deep. Inside the stage which the does Luxman cast, the localization of instruments, their 'description' relative to other elements sharing the stage is simply fantastic. With either classical from the Kathleen Battle disc Grace or Jazz from Solveig Slettahjell's Silver, the instruments were always placed in a tacit acoustical environment with decays and echoes. Stage depth was less than with the Belles or Accuphase amplifiers. The vividness of the latter -- include the INT-150 from Pass Labs -- was better but in their case also the result of a treble softening and sweetening. This promotes midrange elements to seem more three-dimensional. The Luxman softens nothing and rounds over nothing. That's why it escapes the trap one must face with the Accuphase E-450 and A-550, namely their slightly raised upper bass. It creates a big sound but you have to be careful not to exaggerate it lest it become overbearing. With the Luxman that's exactly the opposite. We need to add some fleshiness but may then be sure that nothing will drone or buzz and the dynamics be superior.

That's it. As you can see, the evaluation of an amplifier or any other audio component relies on many elements and will never be unequivocal. What a reviewer should do first is describe the unit as truly as possible, then add assessments relative to specific competitors. Nobody is perfect and Luxman is no exception. Accuphase and Pass offer a sound that's much easier to accept and which you can live with until the end of your days in happiness and satisfaction. The Luxman provokes searching for a better source, for better loudspeakers and finally, for better recordings. As I tried to show about the latter with the Nirvana disc, newer isn't automatically better. But it can be often enough as I learned with Peter Gabriel's IV whose new Japanese remaster is undoubtedly superior. Over the Pass and Accuphase amps, these differences were clear but did not pose the central conundrum which was rather softened. The Luxman played each disc as is, neither trashing it nor concealing a thing. So you need to define your needs and make a decision on what you want from life. If it be peace and stability, the Lux won't help. It is a device for seekers who enjoy taking a risk or two.


Description
Luxman's L-550A II is an integrated amplifier. As usual for this maker, we are dealing with a phenomenally full-featured machine. But at first you won't see the many knobs and buttons, staring instead at those big green fluorescent VU meters confirming power output. Between them and beneath the acrylic cover plate sits a red stand-by LED. I mentioned knobs. There are lots of them. The big ones on the sides select from one of eight (!) line inputs plus a phono input and control volume. There are two buttons next to the first knob to activate a balanced input and switch to MC cartridge. Below the acrylic plate is a row of smaller knobs. The first one selects which input is redirected to the record outputs (there are two which can be switched off and should be during listening), the second one activates one of the two loudspeaker outputs, both or none. There is also a knob for selecting mono, stereo, the left or right channel. Next we have tone controls for bass and treble (a compensation circuit Luxman developed) and balance. The three last controls can be switched off with the 'line straight' button. That is accompanied by a 'subsonic' filter for turntables and a loudness control. To the left we also see a 6.35mm headphone jack.

The business end is equally busy. We get a row of RCA sockets ( the phono accompanied by a gold-plated ground post), six line inputs and below them two XLR inputs. The hot pin is #3 but a switch can change that to #2. Nice and easy. Things sounded better with my Ancient Audio Lektor spinner when switched to the European standard (#2). Two line inputs are grouped with the recording outputs. We also get a pre-out/main-in loop strapped by metal bridges. That's a pity as relays would have been preferable. Adjacent we have two pairs of solid loudspeaker terminals and the IEC power inlet. I don't know why but this model did not get the power polarity indicator likely because the IEC is a two-pin affair.

The inside is segregated into many different chambers by rigid metal plating. In the middle hovers the power supply with a big 450 custom EI transformer with separate windings for left and right output and preamp stages respectively. The protection circuits and VU meters run off their own power supply. We see four big Luxman-branded capacitors probably made by Nichicon or Rubycon and two big rectifying bridges with ultra-fast Shottky diodes for the power section on an aluminum heat sink. The whole is not coupled to the bottom cover but a kind of inner shell that functions as an extra shield and vibration damper. On both sides to that section we have the output buffers, big PCBs screwed tightly to the massive heat sinks. Each mono amp runs two pairs of power transistors in class A push-pull. Unfortunately I could not spot any transistor identifiers. Luxman has significant experience in manufacturing such amplifiers because -- at least according to their own materials -- they presented the world's first solid-state amplifier of that kind in 1981. The PCBs for the pre and power amp sections are etched different than usual and without the green mask which according to Luxman negatively influences the copper. All traces are gold plated. The transistor preamplifier section is mounted on two vertical PCBs to the back plate. Here a second PCB houses the volume control Lecua circuit based on JRC chips which switch resistors such that we always only see two resistors in the signal path. This section is controlled by a black Alps potentiometer mounted on the front panel where it acts as mere reference encoder for the chips. The circuit is not balanced and the signal is 'de-symmetrized' right beyond the XLR inputs. This is why I preferred the RCA inputs even where sources were equipped with XLR outputs. The unit uses a patented negative feedback circuit called Only Distortion Negative Feedback (ODNF) in its 2.2A version. It only returns distortion to the input, not the full signal.

The VU meters run their own PCB next to the front panel and the meters themselves are shielded. Their back-lighting can be switched off. The output stage resistors are metalized and the precision capacitors in the entire unit are polypropylene types. The remote is metal but the buttons are small so in use it is not very handy. The enclosure is made from many materials which the company claims "breaks resonances". Hence the top cover is steel, the vents a plastic mold (the only thing I do not like here) and the side panels thick aluminum. Everything is rubber damped in many places. The top cover is bolted to the side panels and those to the main chassis with only four bolts. The latter are not torqued down tightly but with deliberate give to 'tune' the enclosure and prevent high-frequency resonances. These bolts are adjusted with dynamometric keys. I wonder whether the Polish hardware stores have those...

Specs provided by Luxman
Sinus power: 2 x 20W/8Ω; 2 x 40W/4Ω
Harmonic distortion 0.006% or less (8Ω/1kHz); 0.03% or less (8Ω and 20Hz-20kHz)
Input sensitivity/impedance: Phono MM 2.5mV/47kΩ, phono MC 0.3mV/100Ω, line 180mV/42kΩ, balanced line 180mV/79kΩ, main in 450mV/51kΩ
Output voltage: Tape 180mV, pre-out 1V
Signal/noise ratio: Phono MM over 91dB, phono MC over 75dB, line over 106dB
Frequency response: Phono 20Hz-20000Hz (+/- 0.5dB), line 20Hz-100000Hz (- 3dB)
Power consumption 280W
Weight 22kg
Luxman website