Audio Research LS28 Stereo Preamplifier Reviewed

Published On: September 25, 2017
Last Updated on: October 31, 2020
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Audio Research LS28 Stereo Preamplifier Reviewed

Ben Shyman auditions the LS28 line-stage preamplifier from Audio Research Corporation's Foundation Series. This $7,500 preamp utilizes four 6H30 tubes in its analog circuit and features balanced and unbalanced connections.

Audio Research LS28 Stereo Preamplifier Reviewed

By Author: Ben Shyman

Ben Shyman is an AV reviewer based in New York City. His interest in audio/video gear began in the late 1980s when he worked as a salesman for a regional AV retail outlet in northern New Jersey, selling brands such as Adcom, Sony, Bose, Sunfire, Nakamichi, and Pioneer. He published his first review on in 2004. His specialties include bookshelf speakers, audiophile electronics, and high-resolution source components. Ben fully embraces the digital future of music, including streaming audio, and believes in high-end elegance and simplicity in constructing AV systems.

Audio Research Corporation (ARC) has been a leader in high-end audio electronics for almost 50 years. In an industry filled with companies that come and go or fail to become globally recognized brands, ARC has stood the test of time with components that are coveted by enthusiasts--not just for their sound, but also for their craftsmanship and the company's notable customer service. ARC will repair, refurbish, or restore most of the products it has produced to the best of the company's abilities. Try and say that about any other product you own--audio, video, or otherwise.

Furthermore, ARC still designs, manufactures, and tests every component it ships from its Plymouth, Minnesota, facility. It's a global brand, yet everything is still 100 percent "made in the U.S.A." Audiophiles familiar with the aftermarket for audio gear know that ARC's products maintain their resale value nicely. This is especially true of the Reference Series preamplifiers.

In 2016, ARC introduced the Foundation Series, which includes the LS28 line-stage preamplifier ($7,500), the PH9 phono stage ($7,500), the DAC9 digital-to-analog converter ($7,500), and (most recently) the VT80 power amplifier ($8,000). It was ARC's goal to ensure that each component in the Foundation Series would share the same pedigree, design, and build quality of the higher-end Reference Series, in which the products cost two or three times as much. Much like the components in the Reference Series, the Foundation Series utilizes 6H30P vacuum tubes in its analog circuits.

As a member of the Foundation Series, the LS28 preamplifier is the company's introductory line-stage preamplifier. In ARC's preamp product hierarchy, it sits beneath the REF 6 ($14,000). The biggest difference between it and REF 6 is that the LS28 utilizes four 6H30 tubes in its analog circuit, while the REF 6 utilizes six 6H30P tubes in its analog circuit, as well as one 6550WE and one 6H30P in its power supply.


The Hookup
The LS28 arrived exceptionally packaged in an oversized box. The company was even kind enough to include a full-sized Stanley screwdriver for removal of the cover of the LS28, which you need to do in order to install the tubes. I inserted the four separately packaged, clearly labeled tubes, which ARC had already burned-in, tested, and electrically matched at the factory for maximum reliability and performance. The inclusion of the screwdriver was an expert touch that reminded me that, when you buy high-end, the tiniest details count. It would have been easy for me to grab a Phillips-head screwdriver out of my toolbox, but ARC likely did not want to interrupt my first impression of the LS28 with such a distraction. The unit also arrived with a Quality Assurance Certificate, initialed in 13 places to verify the entire manufacturing process--everything from assembly to final listening tests were notated.

The LS28 is available in a black or natural finish (mine was in the natural finish), weighs 15.9 pounds, and measures 19 inches wide by 6.5 inches high by 13.7 inches deep. A legacy design of ARC that's included on the LS28 are the handles on the front, which extend the total depth by another 1.6 inches. The front panel contains two large knobs for Input Select and Volume, plus six buttons for Power, Menu, Enter, Mono/Stereo, Phase, and Mute. A large fluorescent green display located in the center of the faceplate is sharp and easy to read, even from a distance.

Around back, you'll find four pairs each of balanced and RCA analog inputs, as well as three pairs of both balanced and RCA outputs (two main, one record). It also contains an RS-232 connector for added convenience. The metal IR remote is heavy, well balanced, and includes all the essentials to keep you in your listening chair for hours of maximum enjoyment.


Hooking up the LS28 was simple. I used Wireworld Eclipse 7 cables throughout, running balanced interconnects from a Mytek Brooklyn DAC (link required when published) to the LS28 and RCA interconnects from the LS28 to a First Watt SIT-2 Class A amplifier. Since I run only digital sources, the DAC served as my input switcher, which requires that only a single balanced input be run to the LS28. I used a Wireworld Eclipse 7 power cable in place of the stock cable.

The LS28's menus are thoughtful and functional, and there are several really nice features worth mentioning. Auto Shutdown turns the unit off after a specified time when it's not in use. This helps preserve tube life, which is estimated at 4,000 hours. The Volume Reset feature tells the LS28 to either remember the volume setting for each input or reset it to zero after powering down. The default is zero, which I left unchanged. I also appreciated that ARC programs the LS28 to power up in mute mode. This prevents accidental volume spikes that can result from leaving the volume up during a prior listening session. The remote includes an Hours button that showed me the LS28 had 400 hours of use when I began my critical listening.

Charles Mingus writes in the liner notes of Blues & Roots (Atlantic, TIDAL MQA, 24/192) that he recorded the album in response to critics who said he did not swing enough. Less eclectic than preceding albums like Pithecanthropus Erectus or Mingus Ah Um, Blues & Roots is firmly grounded in gospel church music and New Orleans-style jazz and blues. And yes, it swings. "Wednesday Night Prayer Meeting" and "Moanin'" are the album's most notable tracks. Both songs feature a cornucopia of melodies and rhythms, which I found more decipherable and transparent through the LS28. Mingus' bass on "Moanin'" was presented with greater depth and punch, and the featured baritone saxophone, a masculine instrument in its own right, was full of muscle. The LS28 revealed itself as a highly musical preamplifier that could breathe life and air into a recording and which had me feeling closer to the intention of the artist, as much as that is possible with Mingus.

Charles Mingus - Moanin'

Growing up my parents listened to a lot of Bobby Darin, and I remember hearing "Mack the Knife" in our home like it was yesterday. Recently, my wife and I have been watching House of Cards on Netflix, featuring actor Kevin Spacey. This prompted me to play for her excerpts from the Original Motion Picture Soundtrack to Beyond the Sea (Rhino, TIDAL). Spacey directs the film, plays Bobby Darin, and expertly sings Darin's hits. The arrangements are true to Darin's originals, and the recording--from Abbey Road Studios--is modern and refreshing, with some serious musicianship. Transparency and imaging on the up-tempo "Hello Young Lovers" contained a sense of improved three-dimensionality with the LS28 that had Spacey squarely placed in front of his band, with drums and horns behind him. The double bass on "Mack the Knife" was smooth, round, and full. It provided the essential amount of swing to honor Darin's most famous song, which won him a Grammy in 1959. Finally, the horn arrangements on "Beyond the Sea" were bright and jazzy, all adding to the overall enjoyment of the listening experience.

Mack The Knife - Kevin Spacey as Bobby Darin

In the mid-1980s I saw Rush fans at the Meadowlands in New Jersey boo the band Marillion off the stage in the middle of playing their Misplaced Childhood album. It was a disgusting and sad display of fandom, and after the show I bought Misplaced Childhood. I could not believe my ears. It was awesome. I remain a big Marillion fan, at least of those albums featuring lead singer, master poet, and brilliant songwriter Derek W. Dick (aka Fish). Misplaced Childhood would eventually achieve Platinum status, and in July 2017 it was released as a Steve Wilson-remastered deluxe edition (Rhino/Parlophone). The Wilson remaster is available on TIDAL and contains Marillion's only hit single, Kayleigh, an apology from Fish to the women he dated and, presumably, the relationships he destroyed. Through the LS28, Fish's voice floated in space, and Steve Rothery's extended guitar solo contained a tone that was extended and relaxed, with the distinguished musical fingerprint that screamed Stratocaster.

Marillion - "Kayleigh"

The guitar introduction on "Waterhole" (Expresso Bongo) moved with an exaggerated yet pleasing eeriness across the soundstage from left to right and back again. Percussion, played with aggressiveness and anger, was deep and full yet clearly separated, complemented by a cascading xylophone track solely in the right channel. My favorite track on the album is "Childhood's End." It is always pleasing to hear new things in a recording, and for the first time I was able to clearly discern an acoustic track in the left channel during the verses. The LS28 made listing to Misplaced Childhood more thrilling, intriguing, and emotional than I had ever experienced before.

Marillion - Childhood's end?

Eddie Vedder's second solo effort, Ukulele Songs (Monkeywrench, TIDAL), is a unique album. Not every day does a mega-rockstar self-produce a folk album with the focal instrument being the ukulele. Despite Vedder and the ukulele being an odd combination, he proves highly adept and skilled playing this miniature guitar. The presentation is generally simple, with Vedder and the ukulele occupying center stage. The LS28 breathed added life into the transparency and openness of the presentation, making Vedder and the ukulele sound more live. On both "Broken Heart" and "Dream a Little Dream," Vedder's vocal track was forward and powerful, singing deep in his range, but never overcoming or bearing down on the diminutive Hawaiian chordophone. In my view, this was due to the excellence of the recording but also the LS28's ability to render complex passages with delicate precision. Most tracks on Ukulele Songs are love songs, and none are better in my view than "You're True." It was with this song that the LS28 performed near its best, presenting several clearly distinguished ukulele tracks, strumming frenetically, combined with a classic Vedder-esque vocal track with falsettos and his occasional throatiness.

Eddie Vedder - You're True (Free Album Download Link) Ukulele Songs

"Sleepless Nights," a duet featuring Glen Hansard from The Frames, was also well balanced through the LS28, containing a natural easiness that made listening a joy. Finally, listening to "Longing to Belong" was especially rewarding, as the LS28 presented the cello with enviable timbre and tone.

It was time for some live music, and John Mayer's Try! (Columbia, TIDAL) fit the bill. A blues power trio featuring Mayer on vocals/guitar and studio-professionals Pino Palladino on bass and Steve Jordan on drums, Try! was nominated for a Grammy for Best Rock Album in 2005. Despite collaborating on recordings with Eric Clapton, B.B. King, and Buddy Guy, Mayer has recorded a lot of fluff as a solo artist throughout his career. Try!, however, features some of his best works, combined with covers from Jimi Hendrix and Ray Charles. It is hard to argue against Mayer's serious guitar chops, and the trio's chemistry--a heavy groove and feel--works well, despite long blues jams that break no new ground and are way too reminiscent of The Jimi Hendrix Experience. Jordan's snare drum, played snares off, on Ray Charles' "I Got a Woman" was hard and dry, setting a deep groove through the LS28 preamplifier that was forward and powerful. You could almost feel the tension in the drum. On "Something's Missing," Palladino's bass contained a robust bottom end.

"Gravity" and "Vultures" are two of my favorite Mayer originals on the album, and the LS28 was able to bring me closer to the emotional outpourings of these performances. Mayer, Palladino, and Jordan excel at providing each other plenty of musical space on these tracks, but through the LS28 each song sounded more open than I have heard in the past. If I had to describe the greatest impact the LS28 had on Try! it would be in helping the live performance sound even more live than with other preamplifiers I have heard.

John Mayer Trio - Vultures

While the LS28 is obviously a music-first preamplifier, it is also adept at improving the dynamics and overall realism of movies. During my time with the preamplifier, my wife and I watched numerous movies, including The Zookeeper's Wife, Arrival, Collateral Beauty, and Hell or High Water. To me, vocal clarity is by far the most important aspect of movie-watching, and the LS28 was exceptional at voicing and tone, as well as soundstage placement. With respect to sound effects, the LS28 also performed well in my two-channel system, adding that extra sense of realism and space to the overall quality of the soundtrack. Your priority should be two-channel music with the LS28, but I feel comfortable saying that it does justice to movies if your system is configured for two-channel home theater, as well.

The Downside
As my listening hours exceeded 400, the ARC LS28 sounded better and better. By the time I began critical listening for this review, it was hard to find much in the way of sonic flaws. It just sounds that sweet. However, no unit at any price exemplifies perfection, and the LS28 does have some functional downsides. For one, it's an analog-only product. If any of your sources are digital, you'll have to add in your own DAC (as I did), which adds to the overall expense.

An odd quirk in the Auto Shutoff feature sometimes had the unit powering down when watching movies/television. I guess that could be fixed by extending the shutoff time from the default two hours to something greater, but under that option it would add significant hours to the tubes over weeks and months.

Also, having some ability to choose alternative remote codes would be appreciated. My new Oppo UDP-203 Ultra Blu-ray Player severely interfered with the ARC LS28's left/right balance controls. Of course, Oppo could also provide alternative remote codes, which would also solve this problem.


Comparison and Competition
I had difficulty finding other tube-based preamplifiers right around the LS28's $7,500 price point. But here is a list of other noteworthy stereo preamps, both tube-based and solid-state: the McIntosh C48 ($4,500), the PrimaLuna Dialogue Premium ($3,199), the Luxman Classic CL-38U ($4,490), the Parasound Halo JC2 BP ($4,495), the Pass Labs XP-10 ($5,250), the Ayre Acoustics K-5xe ($4,350), and the Simaudio Evolution 740P ($9,000).

The LS28 left me wondering about the end of the road in audiophile land. Where does a hobbyist go when spending $7,500 gets you a component as luxurious and high quality as the LS28? There are some exotic preamplifiers costing two or three times as much, even from Audio Research, that are unlikely to sound two or three times better. Or do they? Before spending that kind of coin, does it not make more sense to substantially upgrade your room and then your amplification or speakers? Combined with the fact that no other company on the market can equal the service and support offered by ARC, the value proposition for the LS28 is substantial.

Sonically, the LS28 will enhance the musicality of your system through its precise and open soundstage that I can only describe as airy and transparent. As a tube preamplifier, it sounds warm and full, but not overly so. In my view it has a relaxed sound that does not get in the way of the music but rather enhances the overall enjoyment of the presentation. And in my view, that is exactly what a good preamplifier should do. It matched fantastically well with my solid-state Class A amplifiers from First Watt and Pass Labs, which can sound tube-like and three-dimensional in their own right. The LS28 added more speed and punch in the bottom octaves, smoothness in the midrange, and clarity in the highs. Overall, the Audio Research LS28 is without question a fantastic performer.

Additional Resources
• Visit the Audio Research website for more product information.
• Check out our Stereo Preamplifiers category page to read similar reviews.
Audio Research Introduces Trade Up! Program at

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