Audio Research LS28SE Preamplifier | REVIEW

The Audio Research LS28SE line stage preamplifier arrived at a time when I was playing with lightning in a bottle,  a small project line stage utilizing a simple point to point OTL circuit and hot-rodded with some very pricey Bendix 6900s as the primary gain device. A keen-eared EE friend of mine brought it over as an amuse-bouche of sorts. I can’t write about such playful antics however, as they don’t represent real products, but as anyone who’s played with exceptional DIY and modifications knows there are sound realms that exist outside our traditional good, better, best conception of marketable hi-fi products. 

Much like that experiment, which captures lightning in a bottle, Audio Research exists outside the traditional conception of what high-end audio is in 2022–at least in my mind. I’ve heard the brand many times, and always associated it with brands like Wilson, McIntosh, B&W, and a host of other giants of the industry. Yet this is not entirely an accurate accounting of a brand, which also stands apart by being a smaller company, both previously and now with its fresh independence. There’s that evidence of careful listening and tuning that often comes only from individuals who are totally dedicated to their craft. Designers who are also audiophiles are a rarer breed than you might expect. 

Words and Photos by Grover Neville

I digress, but I’ll stand by the idea that there is a certain something to the Audio Research sound which has always been compelling to the true high-end aficionado. Valerio Cora of Acora Acoustics, a designer for whom I have a huge amount of respect, has praised ARC gear, and I’ve heard it matched to impressive effect with ProAc, the brand of my own personal speakers. 

The Story of the Audio Research LS28SE

My initial contact with ARC, concerning this review of the Audio Research LS28SE, started shortly after the company had become independent of McIntosh. Despite that challenge shipping and contact with the company was swift, efficient and pleasant. The box that arrived was not elaborate, but well packed, with a few pieces of precisely fitted foam that made unpacking as quick and easy as the process of arranging the review sample. A remote, four 6H30 tubes, a power cord, manual and the unit itself constituted the entire contents of the box. 

Setup required unpacking the 6H30 tubes, which came fitted with rubber rings–presumably to address potential microphonics, which I never encountered during the review period–unscrewing and sliding off the top of the chassis, installing aforementioned tubes, and putting the top back in its place. The entire process took less than five minutes at an unhurried pace, and I appreciated how well the tubes were packed. Once that’s done, the Audio Research LS28SE is ready to rock and roll. 

Audio Research LS28SE Developments

The Audio Research LS28SE came with a few interesting additional features, some of which I haven’t seen before on a line stage. The retro green LED menu gives you the typical array of input selection, volume indication, and even a phase inversion and mono function, which are quite handy though seldom included in hi-fi. Also included are a home theatre bypass, an interesting tube hours indicator and an input-naming function. While the interface isn’t quite as slick as the Naim or Mola Mola units I’ve reviewed previously, it was nice that ARC has given you a thorough range of options and tools that make this unit feel complete in a way that an expensive line stage should, and I noticed that when I returned to using some of my other line stages. 

The input-naming function came in handy because it meant I could plug everything into the unit at once and not have to perform the dreaded reach around and fumble around in the back end. Plus, the Audio Research LS28SE comes with a ton of i/o. Four balanced and four single ended inputs, two each single ended and balanced outputs, and a balanced and single ended tape record out. I don’t remember the last line stage that let me plug in eight different sources, and seamlessly compare balanced to single ended regardless of the output connection type. This is very much a reviewer’s dream in terms of flexibility here. 

One final thing I’ll mention before diving into sound is the build quality. ARC has eschewed the Nagra or Boulder methodology of huge billet aluminum panels and sold chunks of milled metals, instead opting for a simpler, thinner metal chassis. Panels are smooth and go for clean lines and thinner profiles, all of which ends up focusing your attention on the very classy black information panel on the front. I personally like this functionality, and the unit is surprisingly lightweight despite its size.

All of this added up to something that was easy to take in and out of the system, and similarly simple to unbox or put away. For those looking for an excessively heavy chassis with expensive and fanciful metalwork, the Audio Research LS28SE is not it. All attention here is on great functionality, ease of use and the sound.

eARCandy

Clarity and detail have always been hallmarks of the Audio Research sound, in my experience, and here we have them in abundance. At times, the dirty D word has also come up. (I’ll give you a moment to excise your internal juvenile.) Dryness is a term often used as an insult by those who like a somewhat longer, wetter decay time and find a more damped sound not to their taste. 

Myself? I’ve been living in the studio world long enough that a certain kind of dryness can be quite enjoyable. Certain pieces of gear, such as the Weiss DAC502, have a dry sweetness to them. They are prosaic yet somehow musically compelling, usually because said damping comes alongside a careful tuning that does not imprint itself in an annoying way on the sound. Thus, if we hold the word dry to mean a generally more damped, tighter sounding decay which tends to give us more perceptual texture, we see how this is not a bad thing at all in moderation, but rather a certain flavor or character. 

This in mind, the Audio Research LS28SE, is nearly dead neutral to my ears. What small character it does have, however, draws my ear ever so slightly to the treble. It is not so much a tilt to the frequency response, but more of a sense that bass levels, especially on modern records with occasionally misbehaved low ends, get tightened up and reined in while the upper regions have an appealing openness and clarity to them. Across the entire frequency range, everything is devoid of harshness yet dense with texture. If it seems like I’m reaching for some oxymorons here, it’s because the LS28SE is a tremendously nuanced and difficult beast to describe when it comes to the sound. Transparent is a good start, but it doesn’t go nearly far enough. 

$10,000 is a lot of money, at least to my sensibilities, and certainly for a preamp which is a company’s least expensive offering. What the very best line stages do, however, requires a subtle appreciation of source gear. Most line stages or volume controls make your system sound a bit worse to various degrees, while a much smaller more elite group of good preamps do minimal harm to the sound. This second group is where most hi-fi preamps live, happily imparting their various colorations while mostly letting the amplifier and associated phono or DAC do its thing. However, there is a third category of truly exceptional preamplifiers that, when inserted in a system, actively enhance the sound of a stereo system. 

The Audio Research LS28SE is one of the few line stages I’ve heard that fits into that third category. It stays mostly neutral but steers the system gently into a realm of clarity, openness and control that is  addictive. What it does not do is offer wild party bass or seductive treble sparklies. At times I thought I detected grain, or extra grittiness in the bass, but it always revealed itself to be an extra texture inherent on the recording. 

For me, the Audio Research LS28SE revealed the essence of the ARC Sound. If it had sounded like the stereotype of overdamped, bright bling-fi, it would not have held my attention–I run two ways with Alnico tweeters, pulp cones and Directly-Heated Triodes, as old school as they come, and I was riveted while listening to the LS28SE. 

The Audio Research LS28SE Sets Sail

While concluding my thoughts on this line stage, I’m still discovering new revelations. The Audio Research LS28SE is, pretty much, the best line stage I’ve had in my own system. I qualify that only because it’s difficult, in unfamiliar systems, to know what difference the line stage is making compared to the more dramatic variables such as amp or speakers.

That said, I think if you’re looking at a line stage and have $10,000 to spend, you’d be hard pressed to find anything under this price that will even come close to the ARC. I tried a half dozen of my favorite alternatives and none of them came close to touching the ARC. However, you won’t hear those distinctive tube-like qualities, even though imaging performance was excellent (as it usually is in my system). In addition, you won’t get those dramatic or theatrical bass or dark, chocolatey midrange tones.

The sound of the Audio Research LS28SE is basically truthful, ultra-refined and textured, with obvious strengths in the higher octaves. I found the result to be a sound which spoke more to my head than my feet. I had no problem going deep with tunes, so this is more a point about system matching, which is to say you need to make sure your system is up to par with the LS28SE. When I paired some less expensive source gear or amplifiers with the unit, it had no issues illuminating exactly where they were lacking, and in a way that some other less detailed preamps did not. The LS28SE was never the source of any harshness, nor did I feel it was unflattering, but it did sound refined enough to let me know when certain gear wasn’t pulling its equivalent weight.

I think most of what I’m trying to convey here is that this is a mature product. For the hardcore audiophile, Audio Research has always been there, ready to provide that earnest, detail-rich sound, and this preamp continues that tradition. A $10,000 preamplifier is a big purchase, but this product, to my ears, sits firmly in the high-end sound category, and I never questioned if the price was unreasonable for the sound quality on offer. If you’re ready to hear what a truly high-end line stage can do, the Audio Research LS28SE is one of those rare preamps that will truthfully elevate the sound of your system.