I first came across Line Magnetic Audio several months ago, while browsing Internet audio forums. There was a great deal of buzz about the company, and especially about their field-coil speaker, inspired by Western Electric’s 755A drive-unit. A search led me to a Chinese website that had some astonishing designs -- massive horn speakers, and amplifiers that took up an entire vertical rack, mounted on casters and sprouting exotic tubes and myriad gauges. They also had more conventional tube amps, one of which, the Line Magnetic 211IA integrated amplifier, I auditioned and used in my recent review of Contrast Audio’s Model One As3-Ref loudspeaker. I was very impressed with the fit, finish, and sound quality of the 211IA, which is based on the EL34 tube. Sridhar Reddy of ARN Systems, the Indian importer and distributor of Line Magnetic products, suggested that I consider reviewing the KT88-based 216IA integrated amplifier ($1850 USD), and was enthusiastic about its sound. I exchanged e-mails with James Hwang, Line Magnetic’s director of international sales, to learn more about the company and its products.
Line Magnetic Audio is based in Zhuhai,Guangdong province, China, where it was founded in 2003 by Zheng Xi, an engineer with 20 years of experience in audio electronics, some of it with Cayin Audio. Line Magnetic began by repairing drivers and other products once made by the-now defunct Western Electric Company. Realizing that many music lovers still coveted the WE sound, they decided to start designing and making affordably priced audio components inspired by original WE models. In 2009, they expanded their product line from the classic WE products to tube amplifiers and digital electronics.
The Line Magnetic 216IA integrated amplifier is fairly small -- only 14.5”W x 8”H x 13”D -- but it’s a heavy, lopsided load. Its three transformers sit at the rear of the chassis, which means that its 43 pounds are prone to tip backward; care should be taken when lifting it out of its double box. The 216IA’s striking hammer-tone paint finish lends it a distinctively vintage air, and makes it an attractive alternative to the ubiquitous boxes of prosaic black or silver. The amp arrived with its tubes already installed, the power tubes wrapped in protective foam and protected by a sturdy cage. The cage, ingeniously secured with four banana clips that fit into holes in the chassis, is removed simply by lifting it straight upward.
The 216IA’s tube complement consists of pairs of 12AX7 and 12BH7 tubes in the preamplification stage, and four KT88 tubes for the push-pull amplification stage, all arranged in two rows. On the left and right of the top panel are two small Bias Current toggle switches, each with two positions: V1 and V2 (left), and V3 and V4 (right), each position corresponding to one of the power tubes. Next to the outer power tube on each side are two tiny potentiometers for setting the bias level, these also labeled V1 through V4. To the right of the preamplifier tubes is a backlit ampere meter. All of the review sample’s tubes bore the Line Magnetic logo except for the two 12BH7s, which were sourced from Electro-Harmonix. When I inquired about the provenance of the Line Magnetic tubes, James said that they buy tubes from various manufacturers based on the tubes’ specifications, and that most of the 216IA’s tubes were supplied by Shuguang.
The front panel is finished in silver. It has rotary knobs for Volume (left) and Source selection (right) and, next to the Source knob, a toggle switch for selecting between Triode and Ultralinear operation. There are also an indicator light and an IR remote sensor. The power switch is on the left side panel, and all inputs and outputs are on the rear. Plastic dustcaps for the four line-level inputs are a welcome frill, protecting any unused RCA sockets from gathering dust and grime; the speaker outputs are good-quality, five-way binding posts. Each output connection has taps for speakers of 4 and 8 ohms. Point-to-point wiring is used throughout the 216IA, which is specified to output 22Wpc in triode mode or 38Wpc in ultralinear, with total harmonic distortion of 1% at 1kHz. An input sensitivity of 220mV and an impedance of 100k ohms round off the specification list. The remote control is a nice, substantial chunk of machined aluminum, but has only Volume and Mute controls.
Biasing and setup
Biasing the 216IA’s power tubes consists of setting one of the Bias Current toggles to the tube to be biased and then, with a small flathead screwdriver, turning the corresponding pot while observing the ammeter, the objective being to get all four tubes to measure the same amount of bias current. The procedure is relatively easy except for the fact that the 216IA must be turned on for at least ten minutes before setting the bias, and by that time the tubes are quite hot -- trying to position and turn a screwdriver only an inch or so from a hot tube is tricky. The manual, which is passably translated and adequately informative, recommends the use of matched power tubes. At first I used the 8-ohm taps for my reference speakers, Harbeth Super HL5s, but found that the 4-ohm taps gave better grip and authority. James recommended that I burn in the tubes for 100 hours for the best sound, and ARN assured me that my demo sample had already been adequately conditioned. One more thing: When the 216IA is turned on, its mute circuitry is activated for a few seconds while the tubes warm up.
I began by luxuriating in the alluring, smoky voice of Melody Gardot singing “If the Stars Were Mine,” from her My One and Only Thrill (16-bit/44.1kHz FLAC, Verve/Qobuz). The 216IA portrayed the sultry Gardot with all the authenticity and three-dimensionality of a real human voice. The reproduction of her voice was pristine, with no hint of grain or sibilance, and sounded smooth and lush. The densely orchestrated arrangement of “Mother Father,” from the Dave Matthews Band’s Everyday (CD, RCA 67988-2), was depicted cleanly, with excellent separation of instruments, adequate air and openness, and no congestion. The soundstage itself was quite expansive, its dynamic envelope stretching significantly across and behind the speakers’ positions and with height that extended at least 3’ to 4’ above the loudspeakers. It was as good as I have experienced with my Harbeth SHL5s. Imaging was good, with guest artist Carlos Santana’s distinctively wailing guitar clearly highlighted at the right rear of the stage, and Matthews’s voice front and center, albeit with a slight fogginess.
Joshua Redman’s sumptuous saxophone lines were mesmerizingly sweet and silky in “Courage (Asymmetric Aria),” from his Beyond (16/44.1 FLAC, Warner Bros./Qobuz). The reproduction of the mid-treble and high frequencies was not reticent or laid-back, nor was it sizzling and aggressive -- it sounded just about right. In triode mode, the saxophone sounded slightly richer and more refined; I ended up preferring this setting for jazz and small ensembles, as it helped create an impression of a snug, intimate atmosphere. However, rock and big bands were better served by ultralinear mode, the added power generating larger scale and wider dynamic range. Ultimately, however, such variables as type of music, speaker sensitivity, and size of listening space will dictate which mode will work best for you.
Though its appearance is retro, the 216IA’s sound was definitely not soft or polite. The perspective was clearly front-of-hall, the music appearing at or slightly forward of the plane described by the speaker baffles, and creating a desirable sense of immediacy and palpability. “La Derniére Bergére (The Last Shepherdess),” from Chasin’ the Gypsy, saxophonist James Carter’s excellent tribute to Django Reinhardt (CD, Atlantic 83304-2), begins with a guitar solo. The 216IA presented this very cleanly, deftly stepping out of the way without smearing the transients of the plucked strings, which sounded well defined without being etched or exaggerated. Hank Jones’s melodious piano in the Great Jazz Trio’s Standard Collection Volume 1: Summertime (CD, Limetree 8711458003131) was depicted with accurate timbral fidelity, the sound replete with tonal color and harmonic overtones that alternated between solemnity and levity, as the composition dictated. However, the size of the instrument was a bit smaller than what I’m accustomed to hearing from this recording.
In the Claudio Filipini Trio’s Facing North (16/44.1 WAV, CamJazz), the kick drum in “Scorpion Tail” was sufficiently visceral, with enough pace and rhythm, to underpin the tune. The double bass was well extended, with excellent pitch definition. Indeed, the 216IA reproduced the bass frequencies of all the recordings I listened to exceptionally well -- they were taut and well articulated, never flabby or mushy. The title track of the Manhattan Jazz Quintet’s Autumn Leaves (CD, King CDJ625) is a mellow composition but nonetheless has some explosive interludes from drummer Steve Gadd. Though I’ve heard this passage often, the sudden percussive attacks were very startling, the 216IA grabbing hold of the signal and reacting swiftly, controlling these macrodynamic shifts with ease.
Regardless of the music or recording, I rarely turned the volume knob past 9 o’clock. The manual provides no gain specification, so I checked in with James and learned that the 216IA has a gain of 36dB -- perhaps one of the reasons I couldn’t be too heavy-handed with the volume. I also had to experiment with cables. At first I used Signal Cable’s Silver Resolution Reference interconnects and speaker cables, but in extended listening sessions -- perhaps due to the Line Magnetic’s big, bold, upfront sound -- listening fatigue began to creep in. Substituting Audio Art’s IC3SE interconnects and Signal Cable’s Ultra speaker cables greatly mitigated my discomfort. And when I used an Audio Art Power 1 Classic instead of the 216IA’s stock power cord, I heard superior sound. Trying to further improve the sound, I replaced the 216IA’s stock 12AX7 preamplifier tubes with a pair of NOS Mullard 12AX7s borrowed from a friend. There was a definite increase in overall midrange lushness, the highs sounded silkier and more soothing, and the imaging was more precise. Any prospective buyer should consider a small investment in better tubes. James encourages this, but reminds tube rollers that adequate burn-in time will be needed to achieve optimal sound quality.
I compared the Line Magnetic 216IA with an all-solid-state combination of preamp and power amp. Admittedly, I was concerned about the price gap between the 216IA and my Parasound Halo JC 2 preamplifier and Belles Audio Soloist 5 power amplifier -- together, the latter cost more than 2.5 times as much as the Line Magnetic. However, at 65Wpc into 8 ohms, the Soloist is not hugely overpowered, and having enjoyed the 216IA’s performance thus far, I was optimistic that it would make a convincing case for itself.
The first thing I noticed, and right away, was that the Parasound-Belles combo had more of a mid-hall perspective than the upfront Line Magnetic, and with this, some of the pleasing immediacy that the tube amplifier created was diminished. The expansive soundstage that the tubed integrated threw was still somewhat narrower than the solid-state combo’s, which also produced more holographic, better-defined images.
Tube amps often lose their composure to solid-state in the area of bass slam; though there wasn’t much difference in overall extension, the Soloist 5 exhibited even better control over the bass and thus produced tighter, more textured lows. The treble sounded equally smooth and extended through both rigs, but the Line Magnetic was a touch grainier. I never perceived any shortage of power with the 216A, which was significantly superior at large-scale shifts in dynamics, but the solid-state duo was better at addressing microdynamic nuances. Where the 216IA was decisively a cut above was in the midrange warmth and lushness so eagerly sought by tube aficionados -- it outdid the slightly cooler-, leaner-sounding solid-state pairing. Though this exercise might seem a textbook example of the differences between the respective virtues of tubes and solid-state, I found no clear winner. What impressed me was the Line Magnetic’s strong showing against formidably priced competition.
The Line Magnetic 216IA’s sound showcases the classic strengths of tubes while avoiding most of their pitfalls. It had a rich tonal palette and a musical warmth in the midrange without being analytical or sacrificing musical details, and managed to coax from my speakers a huge soundstage and remarkable dynamic response. Nor did its reproduction of the high and low frequencies take a back seat, sounding smooth and extended in the treble, with bass that was exceptionally taut and textured. Further, the 216IA’s engaging forwardness made the sound come alive -- voices, especially those of women, were remarkably realistic. Its 38Wpc output in ultralinear mode gripped my speakers and drove them relentlessly, with prodigious bass and loudness, while triode mode enhanced smoothness and transparency. With its effortlessly fluent musical flow, the Line Magnetic 216IA integrated amplifier more than made up for its minor shortcomings of providing not quite the ultimate levels of control and refinement. Factoring in the 216IA’s outstanding build quality and its low price of $1850, its ratio of value for money is right up there with the best.
. . . Sid Vootla