Line Magnetic Audio 210IA integrated amplifier review NEW

what more could you ask?
Richard Weiner

What this country needs is a good five watt amplifier - Paul W. Klipsch

I. Synopsis

The LM 210IA is attractive in a way that emphasizes style over fashion, contains more than ample features, at an affordable price.  Oh, and it sounds great, too.

II. A handsome beast

Two brothers started Line Magnetic after repairing and restoring Western Electric amplifiers and speakers. Their perspective, therefore, is from the professional side of audio’s first golden age.  Rather than recapitulate a classic consumer circuit with higher grade components, they are building on the higher performance professional designs.

Their grounding shows. The LM210IA comes in grey enameled hammer tone, the tasteful finish that we associate with vintage theater gear. Shindo Labs dresses its gear to evoke the past, too. And like Shindo, Line Magnetic offers loudspeakers that call upon the past.  They make reproductions of the Western Electric drivers.  The salient virtues of Line Magnetic products are availability (the originals have either rotted, or traveled to the Far East), functionality (they were built this year) and affordability.

When single-ended triode amplifiers hit the mainstream about fifteen years ago, Stereophile reviewers would comment on the price per watt. This was a feeble attempt at humor, and it fleshed out their reports.  When you receive the LM210, I propose that you calculate the mass per power ratio instead.  The amplifier weighs about sixty-six pounds and generates eight watts per channel; a very different story than the ten-pound digital amp I tried recently that put out one hundred fifty watts. Sounded remarkably different, too.  We will come to that soon.

III. A tour of the LM210

The first thing you notice about the amp is a tube cage. I know that reviewers like to talk about the beauty of tubes, how the glow illuminates nighttime listening sessions, and similar idle observations.  Remember the Cary 300B integrated? It’s gorgeous. Emotive Audio preamp with the engraved top panel?  Splendid. Supratek amplifier? Remarkably attractive. The LM210 is handsome but industrial by comparison.

Practical considerations far outweigh the scenery. If a child gets burned on a tube, your listening session will be curtailed by a trip to the emergency department. Curious adults like to touch tubes.  This can lead to blisters and apologies.  If a drink spills or a plate falls on the tube array, it not only stops the music but also creates a very expensive problem. You’re better off with the tube cage.  

If you remove the cage – a simple matter – you find the front row occupied by a pair of 310As flanking a pair of 12AX7s.  The 310A is a 1930’s era driver tube.  The importer claims that it’s sweeter and more musical than the 6SN7s that most circuits employ to drive 300Bs.  The 12AX7s are common, but they provide a simple and cheap opportunity to adjust the unit’s sound and to express my neurotic audiophile compulsion.

Just behind the front row are two hum adjustment potentiometers. I never had occasion to use them because the LM210 is quiet enough not to hiss through my 100 dB-sensitive Edgar horns.

The next row contains a pair of 300Bs. The unit comes with tubes branded Line Magnetic. These perfectly serviceable items became another opportunity for me to experiment with other tubes.

In the middle of the top plate and behind the 300Bs is a pair of 5U4G rectifier tubes.  

The amplifier’s front face contains as many functions as a practical user could request. Rhe top left position is occupied by the input selector knob. RYou get three line level inputs. Below that is a small sensor for the remote control, and below that is the power switch. RNext to that, there’s an LED that shows red when the unit is powered up.

At the center is a large, backlit output level meter. RIf your eyes are good enough, or you’re sitting close, you can watch the meter flick. Although we think of eight-watt amplifiers as restricted to highly sensitive speakers, I found that even speakers in the 89-90 dB range seldom pegged the meter.  

At the top right are three toggle switches. The one on the left turns the power meter light off. Late at night, when you can appreciate all of the subtlety a 300B SET amplifier brings to the music, you won’t be interested in watching a needle swing.  In the center is a negative feedback adjustment. Although the changes were minor during my listening sessions, more feedback produces a slightly tighter and more controlled sound. Less feedback produces a more fluid reproduction. The switch on the right bypasses the line stage and converts the unit to a power amp: another opportunity to indulge the audiophile’s quest for better sound – and more equipment, interconnects and power cable. 

The volume knob is on the bottom right. A small red LED is built into the knob, and flashes when the unit is muted.

The top left back panel has four inputs: the three line level, and the power amplifier-only. All are WBT-style RCAs. There are no balanced inputs in the 210, and I for one don’t miss them.  In home audio, the only time I have heard balanced circuits improve the sound was an Ayre preamp and amplifier combination.  On all other units, it’s a feature that raises the cost but doesn’t help the sound.  

On the top right are the voltage selection switch, the power cord input, and the main power fuse. I didn’t have any reason to change voltage, but I did experiment with several power cords and one fuse. This amplifier is ideal for experimentation, and every change is audible.

Running across the bottom are enormous WBT-style output plugs.  The designers provide 4-, 8-, and 16-ohm taps. A lot of tube gear manufacturers omit the 16-ohm option because it’s another adjustment on the transformer windings and therefore another cost.  But some vintage JBL, Altec or Western Electric speakers present 16 ohm loads.  I’ve had British speakers, like the LS3/5a, that ran 12 ohms. In these circumstances, the sound is better off a 16-ohm tap.

The last feature worth mentioning is the remote control. It’s a simple, hefty block of aluminum that provides volume up, volume down, and mute options. I wasn’t aware of how often I wanted a little more volume, or less until the 210IA come to visit.

IV.  The sound, Part One

As it comes from the importer, the 210IA has the musical refinement we expect from SET amplifiers. The sound is easy, unforced, and flows in a way that no other circuit design can match.  Solid state configurations may offer a tighter grip in the bass (here I always think of Krell and Levinson amps in the 1980s), and more sharply focused treble (sometimes to ear-piercing levels), but none can match the smooth and natural performance of SETs. The midrange, home of strings and voices, cannot be matched by any other amplifying scheme.

I won’t bore you with the question of whether the 300B tube has a characteristic sonic signature. The internet is packed with discussions of whether Western Electric voiced the tube for midrange clarity at the price of bass and treble extension, and counterarguments that it is the most linear device ever released. I will say that the 300B lets the music through with less signature than the EL34, 211, 805 and 845/GM70 tubes I have heard in SET amplifiers. 

I ran the 210IA in my home theater system for a month. It performed flawlessly. If you’ve ever encountered a finicky, problem-prone tube amp, you will appreciate this unit’s steady reliability. 

After I was certain that the tubes were operating at a stable level, I moved the amp over to my horn-based music system. For the most part this consisted of Edgars (100 dB sensitive), with a guest appearance by a pair of Advantgarde Duos (104 dB). Everyone talks about horn systems’ dynamic range, and it’s a valid point: you get a lot more swing from horns than from sealed or vented boxes, even with enormous amplifiers. What many reports omit is the revealing power of horns. Place a shrill amp in front of a horn, and the “revealing, extended” treble you heard with a less sensitive system will be unmasked as grainy and downright intolerable.

For months I reveled in midrange that was both transparent as well as delicate. I compared Heifetz’s reading of the Tchaikovsky violin concerto (EMI 61591) with Oistrakh’s performance of the same (Sony Classical 46339). The beyond-human technique of Heifitz came through the 210IA with remarkable clarity. Heifetz demanded that his instrument be recorded very closely, and you can hear every bow stroke in vivid,

Technicolor sound. Oistrakh’s kick-out-the-jams, barn-burner, toe-tapping approach received equal treatment from the 210IA.  While Oistrakh has technique to burn, his emphasis is on emotion.  

For comparison, I put a well-respected modern solid state amp into that system. The modern amplifier had tighter if not more convincing bass, and what sounded like more detail in the treble; what it lacked was the tonality and timbre, the palpability and almost sensual properties of the 210IA. I was a lot closer to the sound of live performances with the Line Magnetic than I was with the solid state unit.

V.  The sound, Part Two

If I possessed self-restraint, I would conclude this review by telling you that the Line Magnetic 210IA is a robust, highly musical amplifier that I heartily recommend to anyone with above-average sensitivity loudspeakers. You won’t go wrong, especially at the $5,000 price Tone Imports is asking.

But I am an audiophile as well as a conservatory-trained musician, and I wanted to know how much better the 210IA could sound with simple additions. In so doing, I learned an interesting lesson.

If you’ve got a 300B amplifier, the first idea to enter your mind will be changing the 300B tubes. I have a several pairs of Sophia Electric 300Bs, including the Princess carbon plate and the Royal Princess, as well as a pair of Electro-Harmonix Gold Grid 300Bs.  While I found that the Line Magnetic amp was capable of defining differences among these reputable products, I was not swept away by vast changes in sound. I preferred the Royal Princess over the others, but not by a great margin – and the EH tubes are a lot cheaper than the Sophias. The LM tubes are not outclassed by any of the others, and they come with the package.  

Then I swapped out the 12AX7 tubes with NOS Mullard and Amperex specimens I had lying around.  (If you listen to lots of tube gear, you will build up a collection of old tubes, too.) I heard more improvement with those little double triodes than with any of the big 300Bs. The Mullard sound was warmer and more smooth, while the Amperex advanced the definition and added a bit of sparkle.  

That was encouraging news, so I dug up a pair of RCA 5U4-G rectifier tubes.  The Line Magnetic amp became a bit sweeter – not so much as to subvert the unit’s musical integrity, but enough to make listening even more enjoyable. Why should the humble rectifier, whose job is converting AC current from the power transformer to DC current, make a more audible difference than pricy output tubes? I’ll let the online discussion boards argue about it. I’m busy listening to music.

Since each roll of the tubes had produced a change, I searched for a pair of vintage 310A driver tubes. These are neither easy to find, nor cheap when you do.  By luck and with the help of a friend, I managed to borrow a pair of Cunningham 310As.  The magnitude of difference was somewhere between the rectifier and the input tubes. I would encourage you to spend more on the 5U4-G, and leave the stock 310A in place.

The Line Magnetic is so much fun that I put most of my power cords into its receptacle. I found that an old Electra Glide added more body, and an Acoustic Zen Gargantua II produced greater rhythmic drive.  

You can take the amp a step closer to complete transparency with a HiFi Tuning fuse.  I think most electronics benefit from fuse replacement. In this case, I heard a small but noticeable clearing. It’s certainly worth the price.  Other companies manufacture high resolution fuses, so you could indulge your compulsions at a low cost.  

For a lot more money, you can use the LM 210IA as a power amp.  With the Audible Illusions 3A preamp and Acoustic Zen Absolute Silver interconnect, the amp became a little more supple, tracking the music more closely. With the Convergent Renaissance line stage, I heard a substantial improvement in transparency – at the cost of an additional $10,000, another set of interconnects, another power cord, a crowded equipment rack, and loss of the remote control.  

With Mullards, Sophias, RCAs and Cunninghams in the integrated amp, I fired up two favorites. First was Klemperer’s 1961 performance of Brahms’s A German Requiem (Warner Classics 6783302).  This is heroic music making: a gigantic composition, and a titanic conductor reaching toward Heaven. I have never heard every emotion better expressed than with this system.  I put down my notebook and heard the music, familiar since my student days, as though for the first time. To achieve this level of emotion from a bunch of metal casings, some glass envelopes, and pieces of wire is a miracle.
Du Pre’s Elgar Cello Concerto (Warner Classics 91934) is another searing performance that tests the musical capabilities of electronic gear. If this were a movie it would rated as a “five handkerchief” production. Yes, the Line Magnetic gets du Pre’s intonation perfectly as well as the timbre of her instrument.  Beyond those properties lie the elegance and ferocity of the musician. That’s what you’re paying for, and what the LM 210IA delivers.




-Power output:8W+8W(Class A Single Ended)
-Frequency response:10Hz~50kHz(-1.5dB)
-S/N Ratio:87dB(A weighted)
-Input Impedance:100kΩ
-Output impedance: 4 Ω, 8 Ω, 16 Ω
-Input Sensitivity:400mV (Integrated)   1000mV (Pre-IN)
-Tube Complement:12AX7×2、310A×2、300B×2、5U4G×2


- Eight watts per channel, Single Ended design, Pure Class A Integrated Stereo Amplifier with 300B output power tubes. 
- All tube design with 12AX7 input tubes, 310A driver tubes and 300B output tubes.
- 4 inputs and dedicated speaker terminals for 4, 8 or 16 ohm speakers are located on the back panel. 
- One Meter with two pointers is located in the middle of the front faceplate allowing the monitoring of the power output of each channel.
- One piece of specially designed big power EI transformer for power supply and two pieces of Single-ended EI output transformers with wide bandwidth are applied. 
- Japanese Audio grade ALPS volume potentiometer-
- Remote control for volume control and mute.
- Hand made construction with the finest point-to-point wiring.
- Easily installing tube cover for better protection.