The list of high-end-audio companies more storied and more reputable than Audio Research Corporation is short. Though William Johnson sold ARC to the Italian company Fine Sounds Group years ago, all ARC products are still made in the US, and ARC will still service any product ever made over the company’s 40-year history. That is taking good care of your customer, and it’s worth knowing if you’re thinking of dumping ten grand or more into a new box for your home stereo.

The subject of this review, the Reference 5 SE ($13,000 USD), entered the ARC line in late 2011. It replaces the Reference 5, and is the only single-box Reference preamp now offered by ARC. While the Reference 5 SE has since been eclipsed by the Reference 10 ($30,000), the Ref 10 is a two-chassis model, much like the cost-no-object 40th Anniversary Edition, from two years ago; both require twice as much rack space as the Ref 5 SE. After the 250 units of the limited-edition 40 were sold, its cost-no-object features were trickled down to the Ref 5 SE.

At its heart, the Reference 5 SE is a fully balanced, zero-feedback, class-A triode preamplifier that uses four 6H30 tubes in its single-gain analog stage, and one 6H30 and one 6550 tube in the power supply. I’ve owned class-A and a few single-ended amps, and have always felt that they did more with tone and space than their class-AB cousins could ever dream of. However, when your listening room is as small as mine is, living with a class-A amp is like living in an oven -- most of the power they generate is dissipated as heat. Additionally, single-ended tube amps produce none of the bass depth, impact, or power that other class-A or good solid-state amps can. Given my predilection for the sound of single-ended tubes and my knowledge of their limitations, I think that employing such circuitry just before a very good solid-state amp is a very good compromise indeed.

Additionally, the Ref 5 SE employs dual transformers: one toroid for the display and other non-audio circuits, and an R-core for the audio circuits. Both are mounted on the inner side panels. While within the limitations of a single-box preamp this novel mounting arrangement minimizes the potential of the audio signal being infected by vibrations and thus obscure low-level detail, it also contributes to the Ref 5 SE’s considerable size and weight: 19”W x 7”H x 15.5”D and 41.6 pounds.

Functionally, the Ref 5 SE is much like its predecessors: a remote-controlled, six-input line stage with home-theater bypass, line-level bypass for recording (yay!), and dual main outputs. All inputs and outputs are available single-ended and balanced (ARC recommends the latter; the Ref 5 SE’s circuitry is balanced throughout). Also like its predecessors, the 5 SE is a lesson in design convenience: It’s accompanied by a metal remote control with which the user can adjust or select the source, volume, balance, mute, phase inversion, and display brightness -- all features that I used extensively. Although having the ability to adjust volume or mute and select sources from the listening seat is a great gift to the lazy, purists would argue that any such added “feature” can compromise a component’s maximal performance.

But this is the real world; when properly executed, such features are a boon to the listening experience. In my irregularly shaped room, I had to adjust the balance a few notches to center the soundstage and get the proper depth. Further, many of my favorite discs are recorded out of phase; with ARC’s remote, I just toggled the Phase button back and forth, listening for the telltale tighter bass and imaging of in-phase playback. And turning off the display is critical to minimizing any component’s self-noise. Years ago, when I first listened to my Reference 3, I thought it was malfunctioning, so bad was the noise when the display was illuminated. The Ref 5 SE wasn’t that bad, but the noise was still obvious. And for convenience, any time a setting is changed, whether via remote or the Ref 5 SE’s front panel, the display lights up for a few seconds.

Owners of the Reference 5 can upgrade to 5 SE status for $3100 (models earlier than the Reference 5 are not eligible). The most significant difference between the models is that the Ref 5 SE’s power-supply capacitance is twice the Ref 5’s -- and as I’ve said in every electronics review I’ve written, You are listening to your power supplies. Additionally, and perhaps even more important, the key coupling capacitors through which the audio signal directly passes have been upgraded to Teflon. As an avowed modifier of audio gear, I’ve found that upgrading any preamp’s coupling caps to Teflon is a surefire way to improve its transparency and frequency extension. Compare the prices charged for 1µF, 600VDC Teflon capacitors and polypropylene caps of the same size and voltage -- the fivefold increase in cost suddenly makes ARC’s $3100 upgrade seem eminently economical. The other changes from Ref 5 to Ref 5 SE are mostly cosmetic: round metal buttons on the front panel instead of clunky, square plastic ones; and a top plate of nonresonant polycarbonate rather than metal.

The Ref 5 SE’s stock power cord has a 20A IEC connector, and while it acquits itself well, the ARC sounded considerably more transparent, detailed, and dynamic with the TG Audio cord I used. Finally, the Ref 5 SE requires 600 hours of use to break in, which I attribute to the Teflon coupling capacitors -- in my experience, these always take an interminably long time to burn in before the dynamics and the retrieval of microdetails are fully realized.

While the review sample performed flawlessly, the Ref 5 SE’s appearance and build quality were not close to best in class in comparison to some other gear I’ve had. ARC’s well-known brushed-aluminum faceplates have their fans, but that’s small comfort if you’re trying to convince your spouse of a product’s sonic merits when drop-dead-gorgeous alternatives are available from Ayre Acoustics and Jeff Rowland Design Group. While the Ref 5 SE’s display is conveniently large and can be turned off, it’s still an eyesore, even when dark. Further, the two return-to-center knobs on the front panel, one for volume and the other for source selection, feel cheap. I prefer to feel a reassuring click when I select a source, to say nothing of a volume knob with silky, continuous rotation (of course, using the Ref 5 SE’s remote precludes these gripes). That said, I found that, when I sat down to listen to music, I didn’t give a rat’s ass about such things. I focused on the music.

Listening

The Ref 5 SE sounded like its specs: a big, bold, powerful single-ended-triode (SET) tube amplifier, but without a SET’s stereotypical flaws of limited dynamics and truncated frequency extremes, and this character was clearly on display no matter what power amps I plugged it into, provided the amp’s input impedance was greater than 20k ohms, balanced. Otherwise, the bass was ill-defined, recessed, and woolly -- as I found when I partnered the Ref 5 SE with the McIntosh Labs MC501 monoblocks, which have an input impedance of 20k ohms, balanced.

To my mind, any discussion of the sound of a tubed audio component must begin with its noise floor. Tubes are far noisier than transistors, and you can hear the music on a recording only if it’s louder than the noise generated by all of the components in your audio system -- lowering the system’s noise floor is essential to hearing that detail. With the Reference 5 SE’s display on and no music playing, I could easily hear some hiss when I stood a few feet away from the speakers. Turning off the display caused the hiss to disappear, even when I placed an ear only inches from a tweeter. This was a very quiet preamp.

When I played “London,” from She & Him’s Volume 3 (CD, Merge MRG 474), it was easy to hear the reverberant space in the studio surrounding the performance of this torch song by a single female voice (Zooey Deschanel’s) accompanied by piano. This sense of space, delineated by echoes and reverberations, is the first thing that’s lost if the noise floor is too high -- after all, the venue doesn’t make noise; it makes echoes of musical sounds. The Ref 5 SE was sufficiently quiet that hall acoustics and the ambient space around, between, and behind musicians were precisely defined -- when they’d been captured in the first place.

I was most pleased with the absolute level of detail the Ref 5 SE extracted from well-worn recordings. Another simple arrangement, this time of a woman’s voice accompanied by guitar, is that of “World Warrior,” from Nedelle’s From the Lion’s Mouth (CD, Kill Rock Stars KRS 424). Here Nedelle sings to her limits of range and volume, and sometimes beyond; at the latter moments her voice starts to break up, and a very resolving system will reveal this so that we can hear what she felt just as she pulled back on her voice. The Ref 5 SE got that first-scratch-in-the-larynx thing big time.

A hallmark of ARC electronics has long been an expansive soundstage that extends well past the speakers’ outer side panels while also projecting forward, to immerse the listener in the music -- think rows 1-10, not 20 and back. The Ref 5 SE expanded on this with greater solidity of singers and instruments than I hear, for example, through my Ref 3, whose rendering of space is more billowy. The Ref 5 SE’s ability to render such a large, forward, well-defined soundstage will be enough to get some shoppers to pull out the plastic immediately; it was quite unlike any other preamp I’ve heard in its ability to immerse me in the music. This was never better illustrated than when I listened to live recordings, such as Phish’s A Live One (CD, Elektra 7559617772). When the audience’s applause fades in just before the first track, “Bouncing Around the Room,” it kept unraveling in layers, expanding in depth, and increasing in loudness through the ARC, transporting me back to the last Phish show I attended. When I had the same experience listening to a Grateful Dead concert recorded in the Olympia, in Paris, on May 4, 1972 -- before I was born -- I thought of what I offer non-audiophile acquaintances as an explanation of why I spend more on audio gear than on my car: My stereo will take me places no car can. The Ref 5 SE sure took me to such places.

I never heard the Reference 5, but the Ref 5 SE absolutely trounced the Ref 3 in dynamic contrast and freedom from congestion -- in those regards, the Ref 3 sounds downright wimpy in comparison. When I listened to “Moby Dick,” from Led Zeppelin’s live How the West Was Won (CD, Atlantic 7567835872), the Ref 5 SE could jump to life during the start-stop-start of John Bonham’s drum solo with far greater verve than the Ref 3. No doubt part of this improvement in dynamics was due to the Ref 5 SE being the quieter model -- an increase in dynamics is really a reflection of music rising through the noise floor; the lower a component’s noise floor, the more dynamic its sound. But the Ref 5 SE also demonstrated far greater control and depth in the bass. The double bass in “Life on Mars,” from the Bad Plus’s Prog (CD, Telarc 3125), had greater texture (read: microdetail) through the Ref 5 SE than through the Ref 3, while “King Rat,” from Modest Mouse’s No One’s First, and You’re Next (CD, Epic 746289), showed the Ref 5 SE’s superior bass power and control. As the band ramps up to the climax, increasing in intensity and power, the Ref 5 SE never lost control of the kick drums or bass guitar, which fill out the bottom octaves and give the music its foundational heft -- nor did the ARC compress, harden, or lose stage definition as the volume ratchets higher. The Ref 5 simply held it all together, letting the music fly with abandon.

The final point that stood out with the Ref 5 SE was how absolutely complete it behaved when a note ended. Except when compared to the Ref 5 SE, solid-state devices typically have it all over tubes when it comes to drive and moxie -- but at the cost of rushing through the performance, shortchanging the harmonic decays of voices and acoustic instruments (piano, guitar, etc.) in quiet passages. The Ref 5 SE not only had drive and moxie, but when the tempo slowed and things trailed off into nothingness, there was simply more trailing off with the Ref 5. This decay -- full of overtones, ambience, and woody resonances -- is the aural stuff of emotion, the negative space that makes the positive so much more meaningful. Frank Sinatra got this -- how he ended a note was as important to him as how he started it. Listening to “When the World was Young,” from Sinatra’s Point of No Return (CD, Capitol 337402), it’s the majestic decay of his voice in the second stanza, accompanied only by piano, that makes this performance of the song a masterpiece, and the Ref 5 SE let the sounds of voice and piano continue on and on, hanging and decaying, and leaving me hanging in the process, rather than rushing me a moment too soon into the bridge, as I’ve heard solid-state preamps do. At the same time, Sinatra’s voice was simply glorious through the Ref 5 SE, full of depth and power, with none of the upper-bass thinness I hear with the Ref 3. Strings were also more extended, complex, and delineated with the Ref 5 SE, rather than the lovely but subdued and monochromatic top end usually heard from tubes, or the extension with a side order of grain often served up by solid-state gear.

Comparisons

While the Reference 5 SE constitutes worlds of improvement over the Ref 3 in bass depth, impact, and texture, it never reached the subterranean depth, impact, and control I heard from “King Rat” and “Moby Dick” when the Edge Electronics Signature 1.2 preamp ($12,200 when available) was in circuit. And while the Ref 5 SE’s dynamics, extension, freedom from congestion at higher volumes, and pace, rhythm, and timing (PRAT) were all outstanding -- clearly better than the Ref 3’s, or of any other tube preamp I’ve heard -- the Edge was slightly better yet in all of these parameters. I suspect that this was due to its battery-powered operation and vanishingly low noise floor. However, when it came to tone, space, soundstaging, and ergonomics, the Ref 5 SE was clearly superior.

Comparing the Ref 5 SE with SMc Audio’s VRE-1C ($16,950) was an exercise in contrasts. While the VRE-1C was fantastic at PRAT and retrieving detail, it was unable to match the Ref 5 SE’s harmonic completeness, tonal decay, or its ability to render a spacious and well-defined soundstage. “Queen Bitch,” from David Bowie’s Hunky Dory (CD, EMI 0687598), had more dynamic range, pace, and drive through the VRE-1C, but the Ref 5 SE added more acoustic space, tonal color, and decay, making for a more compelling listening experience.

I also compared the Ref 5 SE with Ypsilon Electronics’ PST-100TA passive preamp, which is remarkably heavy (55 pounds) and expensive ($26,000), but whose sound is remarkably transparent. While the Ref 5 SE never left me wanting more detail retrieval or tonality, the Ypsilon was clearly better at both, training an uncolored microscope on all aspects of the music. Being an overbuilt passive design with discrete transformer taps for volume control, the Ypsilon is second to none at providing a clear window on the recording -- but at the price, it should be; it’s the best preamp I’ve heard. With the Nedelle or Sinatra tracks, the Ref 5 SE approached but could never reach the Ypsilon’s levels of detail and transparency. In fact, it was a bit more challenging to take full advantage of the Ypsilon’s transparency -- all other components and ancillaries (cables, footers, etc.) were called into question. With its SET-like character (yes, it’s a coloration), the Ref 5 SE was actually easier to make wonderful sounds with, even if it couldn’t reach the Ypsilon’s heights.

Conclusions

On paper, Audio Research’s Reference 5 SE is designed to sound like a SET. In practice, it does so perfectly, without the usual flaws or suffocating character that I’ve heard from most SET amps. For those who suffer from the solid-state blues, the Ref 5 SE will make almost any system it’s plugged into sound bigger, bolder, more holographic, and more downright musical -- just as a SET will. While the Ref 5 SE lacks the subterranean control and lift of the best solid-state preamps I’ve heard, and the absolute transparency and detail retrieval of the standard-setting Ypsilon PST-100TA, it has more of these things than any other tubed preamp I’ve heard, along with the tone and space that few -- if any -- solid-state preamps can muster. The fact that it does so for thousands less than the Ypsilon makes the Reference 5 SE something of a best buy in the super-preamp category. I can’t recommend it highly enough.

. . . Ryan Coleman
ryanc@soundstagenetwork.com

Associated Equipment

• Sources -- Esoteric K-01 SACD/CD player, Esoteric P-02/D-02 CD transport/DAC, Modwright-modified Sony 5400ES
• Preamplifiers -- Ypsilon Electronics PST-100TA, Edge Electronics Signature 1.2, Audio Research Reference 3, SMc Audio VRE-1C
• Amplifiers -- Boulder Amplifiers 1060, Edge Electronics Signature NL-12.1, McIntosh Labs MC501 monos
• Speakers -- Rockport Technologies Merak and Sheritan II, Avalon Acoustics Time
• Cables -- TG Audio (power, interconnects), AudioQuest Redwood (speaker)

Audio Research Reference 5 SE Preamplifier
Price: $13,000 USD.
Warranty: Three years parts and labor; 90 days, tubes.

Audio Research Corporation

3900 Annapolis Lane N.
Plymouth, MN 55447-5447

Phone: (763) 577-9700

Website: www.audioresearch.com