In 2007, Luxman Corporation released the SQ-N100 tubed integrated amplifier as part of the company's NeoClassico Series, which focused on smaller, space-saving designs. The 12Wpc (into 6 ohms) SQ-N100 proved very popular, both in Japan and internationally, possibly owing to its use of EL84 pentode power tubes, cherished among audiophiles and electric guitar players alike for their midrange-to-treble luster and visceral sense of drive. (For evidence of the EL84's shimmering-yet-gutsy sound, listen to the Beatles' 1963 debut album,, where guitarists John Lennon and George Harrison relied on EL84-fueled Vox AC30 amplifiersfour output tubes per cabinetto create the quartet's then-trademark chiming-but-punchy guitar tones.)

Now, after a hiatus of a few years, Luxman has revived the NeoClassico Seriesand with it, the spirit of the SQ-N100with the SQ-N150 integrated amplifier ($2795), which one-ups the N100 with a moving-coil phono stage. (The SQ-N100, which sold for $2999 when last available, had a MM phono stage only.) The N150 also adds a channel balance control, a chunkier, metal-enclosed multifunction remote (included for the price), backlit output-level VU meters, and a newly introduced P-K split-phase inversion circuit for its class-AB output stage. Four Slovakian-made JJ Electronic EL84 pentode power tubes produce 10Wpc in push-pull mode, alongside two JJ Electronic 12AX7/ECC83 dual-triode input-driver tubes.

Design

I wrote this in my review of Luxman's L-509X integrated amplifier: "Compared to electronics from other contemporary manufacturers, Luxman CD players, amplifiers, and DACs have a look all their own . . . and placed side by side, it would be hard to tell classic Luxmans of the 1960s and '70s from their distinctively styled products of today." These statements also apply to the SQ-N150: It's a sleek machine, with a 5mm-thick aluminum-alloy enclosure, finished in a matte white/silver coating; the same finish is applied to the covers of its output transformers and power transformer. The chassis and rear panel are made of coated steel. A black, snug-fitting tube cage adds a dark flair to the SQ-N150's handsome facade.

The SQ-N150 is small, measuring 11.69" wide by 7.40" high by 9.88" deep; its weight is just over 27lb. As an audio reviewer in a small apartment, I consider this modest sizeLuxman describes the amp as having an "A4" footprintto be a welcome change from the heftier audio components offered by most hi-fi manufacturers.

The amp's user controls are spread across its top and front panels. On the former are a rotary Input Selector switch, followed by three small potentiometers for Bass, Treble, and Balance. On the SQ-N150's front panel are twin output-level VU meters, with a single Display control button. To the right of that are a Line Straight pushbutton switchthis bypasses the tone controlsplus a Phones jack, a Volume knob (with an embedded orange LED that flashes when the volume level is changed), an on-off button labeled Operation (with its own orange LED), and an IR receiver for the remote handset.

The SQ-N150's rear panel includes an IEC jack (two- conductor, no ground), two pairs of gold-plated speaker binding posts, three pairs of line-in jacks (RCA), one pair of phono input jacks (RCA), and a turntable ground post (which provided little clearance for anything besides a single ground connection: bad news if you also need to ground a step-up transformer). Four aluminum-enclosed rubber feet attach to the bottom plate. "Designed, engineered, assembled, tested, and packaged in Japan," wrote John Prawel, Luxman's VP of US sales, in response to emailed questions. "Direct inspection of the SQ-N150 reveals a roster of known Japanese, high quality parts. An Alps motorized volume control, along with 'audio grade' Nichicon UFW/FW capacitors. Additional Panasonic electrolytic and Murata film capacitors are employed along with specialty relays made by Japanese supplier, Takamisawa. JRC (New Japan Radio Co., Ltd.) integrated control ICs are featured where required. High quality 'point to point' soldered, solid core busbars are utilized in combination with com- ponent-populated FR-4 glass-epoxy circuit board(s) having optimized copper traces. Luxman's own OFC (oxygen free, non-plated cable) wire is employed. The VU meters are also custom made in Japan for Luxman."

"The headphone output is taken from the main amplifier output," Prawel noted. "Main speakers are muted when a headphone plug is inserted into the front panel headphone jack. Headphone output is specified at 300mV with 16 ohms impedance. Low impedance headphones are not recommended."

Setup

"The units are not auto biasing," emailed Jeff Sigmund, president of Luxman America, in response to my queries regarding tube biasing. "Tubes are installed, and bias checked for each unit at the factory. Each SQ-N150 is run through a soak test and warmed-up through a full power cycle so that the bias of the output tubes can be precisely set at the factory. Bias shouldn't need to be checked or changed unless/until output tubes are changed. The procedure is quite simple, but since it does require access to the main board (via removal of the bottom cover) we do not provide this information in the owner's manual. Rather, we like to interface with the customer to be sure they have proper instruction, guidance, and safety advice."

As for my other setup concerns: Generally, I find the sound of an MC cartridge is bettered by use of a step-up transformer (SUT), but Sigmund suggested I run my Hana ML MC cartridge ($1200) straight into the SQ-N150. "For your Hana ML cartridge," Sigmund noted, "you should eliminate your step-up transformer and use the SQ-N150's on-board MC input. The MC input has an input sensitivity of 0.33mV/100 ohms loading, which should be near-perfect for your cartridge. Hana actually recommends 100 ohms loading for that cartridge; it should be a very good match."

I used my Kuzma Stabi R turntable ($9595) with 11" Kuzma 4Point tonearm ($6500) and Thorens TD 124 turntable with Jelco TS-350S tonearm ($799) and Denon DL-103 cartridge ($299) to evaluate the Luxman amplifier, along with my Tascam CD-200iL CD player/BorderPatrol DAC SE combination. DeVore Fidelity O/93 ($8400/pair, 90dB) and Klipsch Forte III loudspeakers ($3998/pair, 99dB) with Auditorium 23 speaker cables were also part of the review system.

To achieve good bass response with the Luxman, my DeVore O/93s required closer-toback-wall placement than when I used them with the 40Wpc Cary SLI-80HS integrated amplifier. I ended up with the O/93s' back panels 31" from the front wall and the speakers' front panels 74" from my listening seat. The Klipsch Forte IIIs required similar adjustments to gain satisfactory bass frequency response.

Listening

Before Sigmund suggested I operate the Hana ML cartridge straight into the SQ-N150's MC input, I used a Bob's Devices step-up transformer ($1375) into the SQ-N150's MM input; with most recordings this yielded superb tonal richness, upper frequency definition, midrange warmth, and lower-end weight. I was surprised to find that the SQ-N150's MC input gave me 50% to 60% of what I was hearing with the Bob's Devices SUT; without the step-up transformer there was less bass weight and definition. On the other hand, without the transformer, speed and clarity improved.

My favorite bass-range torture test track is side A of Kraftwerk's Tour De France Soundtracks (2-LP, Astralwerks ASW 91708-1, 2003). Through serene synthesizer blips and bleeps, the album travels a marathon journey of rolling melodies and chirpy drum machine rhythms. Side A culminates in a shuddering 8th-note synthesizer pattern, a stream of nearly subsonic bass notes that some amplifiers might have trouble reproducing clearly. I was surprised when the SQ-N150 replicated this sequence with good warmth and weight in a large soundstage, if not achieving the definition or detail I've heard from my reference equipment. The SQ-N150 replicated the note pattern's pulsing, strobe-like character without sacrificing its flow. Stereo images were well-proportioned in a soundstage that was wider than it was deep.