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Line Magnetic LM-845IA integrated amplifier

Line Magnetic LM-845IA integrated amplifier

If you’ve ever paused in front of a painting by Peter Paul Rubens, you may have noticed that the canvas seems to glow. Everything in Rubens’s paintings celebrates abundance. A golden light bathes his landscapes, and his figures are epitomes of radiant health—the women ample and voluptuous (a body type sometimes called “Rubenesque”), the men vigorous and athletic. Invariably, these expanses of rosy European flesh appear to be in motion, an effect Rubens mastered more thoroughly than arguably any artist of his age.

Rubens’s life was as much of a testament to plenitude and vigor as his art. After several hours of sleep, he worked from 4am to 5pm; as he painted, an assistant read aloud to him from works of classical literature, and afterward Rubens rode one of his Spanish thoroughbreds briskly around his estate to stay fit. The apprentices and assistants in his enormous art factory in Antwerp numbered in the hundreds.

In addition to becoming one of Europe’s most famous and prolific painters, Rubens moonlighted as a diplomat and spy for the Habsburg rulers of Flanders. And when Marie de’ Medici, the queen mother of France, paid him a fortune for a cycle of paintings intended to immortalize her, stipulating that he paint every figure himself, in less than two years Rubens produced 24 monumental canvases that turned treaty signings and other dreary episodes from the queen’s life into the stuff of mythology, surrounding the portly Marie with Olympian gods, angels, and swarms of putti. (Today you can see these ravishing paintings at the Louvre.)

As a widower in his 50s, Rubens married his late wife’s niece, the 16-year-old Helena Fourment, with whom he proceeded to father five more children. (He had three already.) So it seemed entirely in character for Rubens to die from gout, a disease caused by an excess of good living.

The Line Magnetic LM-845IA
Rubens came to mind while I was searching for a way to explain the abundance brought into my life by the Line Magnetic LM-845IA, an integrated amplifier that has altered my understanding of how hi-fi components work together. Everything about the Line Magnetic is Rubenesque: It weighs 77lb, crowds most equipment racks, and its 845 tubes—each the size of an ear of corn—glow brighter than some table lamps. It replaces the company’s LM-518IA amplifier, which Herb Reichert reviewed in 2015 and still uses, happily. What sets the LM-845IA apart from most other commercially manufactured amplifiers is that it uses a single output tube per channel—a topology that many audiophiles revere for its pellucid sound, rich tone, and textural detail—while generating enough power to effectively control speakers of only average sensitivity. As it happens, it has much more to offer, but more about that in a moment.

Line Magnetic is a decidedly unusual company, having gotten its start manufacturing replicas of classic American audio equipment by the likes of Altec, Jensen, and Western Electric. Made in Zhuhai, in China’s Guangdong Province, the LM-845IA is part of Line Magnetic’s more affordable line of original circuit designs with a more contemporary look, though the company’s devotion to prewar tube equipment is apparent here. The LM-845IA relies on a single 845 tube per channel—first released by RCA in 1931 for use in AM radio transmitters—to produce a whopping 22 watts.


It also uses 12AX7 input tubes, a 5AR4 rectifier, and a pair of triode-operated 6P3P beam tetrodes to drive the grids of those slightly terrifying 845s. The output tubes are biased individually, using screws mounted on the top plate of the chassis, with the help of a retro backlit meter mounted on the front. There are also screws for minimizing hum, which work. Also on the front panel is a power switch, which mutes the amplifier for 30 seconds as the tubes warm up; two large, chunky knobs that control volume and source selection—and to my intense disappointment, no balance control. On the back, Line Magnetic conveniently offers 4, 8, and 16 ohm speaker terminals, three line-level inputs, and a preamplifier input for those wishing to use the LM-845IA as a power amplifier. A nicely machined aluminum remote with volume and mute buttons is included.

According to Jonathan Halpern of Tone Imports, Line Magnetic’s North American distributor, the differences between the LM-845IA and its predecessor, the LM-518IA, boil down to changes to internal components and redesigned output transformers, which are still made in Japan and still enormous. Inside the chassis, I spotted an ALPS potentiometer, RealCap capacitors, massive filter chokes, clean point-to-point wiring, and reassuring construction—all suggesting that you get both quality and quantity for your $4895.

Hot Stuff
If you haven’t lived with an 845 amplifier—as I hadn’t—you will soon discover why the tube isn’t more popular with mainstream audio designers. In class A, the tubes’ filaments require potentially lethal voltages and are said to operate at 3140°F. The amount of heat they produce astonished and unnerved me. I first placed the LM-845IA on the bottom shelf of my Box Furniture Co. rack, which allowed about two inches of clearance between the top of the amp and the shelf above it. I turned it on and waited several minutes. When I touched the underside of the upper shelf, I discovered that it was too hot to keep my hand there for even a second; not wanting to find out whether the rack was flame retardant, I moved the amplifier to a Box Furniture Co. amp stand that sat on the floor. I began to unhappily imagine using the Line Magnetic during sweltering New York summers, when its effect on a room’s ambient temperature would be difficult to ignore. I strongly suggest that you leave the tube cage in place, as even the briefest contact between an 845 and your skin will result in a severe burn. Ask me how I know.

Having dressed my wounds and overcome my fear of the LM-845IA, I sat down to listen. What I noticed first were the hallmarks of a well-designed single-ended triode (SET) amplifier: a bell-like clarity, lots of textural information, and a distinctive three-dimensionality to the sonic images. Compared to most push-pull amps, SET amps tend to imbue images with a buoyancy and a high-contrast vividness that some listeners refer to as psychedelic. With the Line Magnetic and the 16 ohm taps, the soundstage was expansive in width, height, and depth, with instruments and voices floating free of and well above my Altec Valencia 846A speakers.

That’s about all the LM-845IA shares with a typical SET amplifier. Like Rubens’s Tiger Hunt, a monumental painting in which armed men with dubious judgment struggle to the death with fierce tropical cats, it epitomizes vigor, power, and physicality. SET amps often get knocked for making slow, puffy, indecisive bass, but the Line Magnetic plays bass that’s forceful, voluptuous without being sloppy, and excitingly tuneful, almost strutting with the right music.

Published at Fri, 18 Jun 2021 16:58:25 +0000