Audio Research Reference 10 Preamplifier

by Marc Mickelson | January 15, 2015


A few years ago I toured a fascinating mansion in Canada. Craigdarroch Castle was built in the late 1880s on a hill overlooking Victoria, British Columbia, by industrialist Robert Dunsmuir, who was the wealthiest and, in all likelihood, most powerful man in Western Canada in the late 19th century. The Castle is one of those grand, hulking houses the rich of that era built seemingly to keep out as much sunlight as possible. What made it so fascinating, aside from all of its opulence, was the story of the Dunsmuir family itself. After the death of Robert in 1889, before his Castle was even finished, his wife and children engaged in the sort of petty in-fighting that families with seemingly endless financial resources do. One of the Dunsmuir sons actually sued his mother, and eventually all businesses, the fortune Robert amassed, and the Castle itself were lost.

While the story of the Dunsmuir family occurred on a large scale, given the wealth of its patriarch, it is not the exception to the rule. Any expert will tell you that one of the most difficult transitions for a family-owned business to make is from the founder, the one person most responsible for its rise to prominence, to the second generation, most often an immediate family member, but not always. The pitfalls of this transition are legion, not the least being that it is often the founder's unique vision that is responsible for the company's existence to begin with, and that's not easy, or even possible, to replicate or replace.

Audio Research Corporation (ARC) has successfully undergone just this sort of evolution, although without the further involvement of family (unless you consider longtime ARC employees family). The company that William Z. Johnson, patriarch and guiding light, founded in the early 1970s sold to a large Italian investment firm in 2008. But the sale to new owners with deep pockets doesn't ensure a smooth transition and continued success. Just read Matt Taibbi's take on KB Toys in Rolling Stone for an example. Audio Research changed hands again, via a management buyout occurring early last year, and a recent announcement has the company evolving yet again with the retirement of president Terry Dorn at the end of 2014.

But from outward appearances Audio Research has remained the same as it ever was. New products have rolled out with near-clockwork consistency, and the company has even made a push to anticipate demand by manufacturing products before they are ordered, so buyers won't have to wait for the items they've just spent thousands of dollars to purchase.

The same sort of successful transition has happened to arguably Audio Research's signature product category -- tubed preamplifiers. The lineage began with the $750 SP-1 in 1972. In 1982, Audio Research created its first two-chassis preamp, the $3500 SP-10, this followed by the company's most renowned model, the $4900 SP-11, in 1985. The first of the single-chassis Reference-series preamps, the Reference 1, came in early 1996, followed by the Reference 2 in 1999 and the Reference 3 in 2004. The Reference 5 appeared in 2009 (there was no Reference 4), followed by the Reference 5 SE in 2012.

In between the Reference 3 and 5, Audio Research signaled that it was going back to the future, releasing another dual-chassis preamp, the Reference Anniversary, to celebrate the company's fortieth anniversary in 2010. The Ref. 40, as this preamp also came to be known, was limited in production. ARC took orders for one calendar year, and much to the company's surprise more than twice the projected number of preamps were sold. This made the introduction of the Reference 10, in late 2013, a near surety, as it became clear that boundary-pushing Audio Research preamps were still in great demand.

But while there are outward (and a few inward) similarities between the Reference Anniversary and Reference 10, the latter is the product of what ARC learned in the interim between the two preamps. First, the similarities. Both have two large chassis -- a line stage and power supply -- that are connected by a pair of serious-looking umbilicals, one for each channel. Both have the same number of balanced and single-ended inputs and outputs (six and two, respectively), and both feature computer-like screens on the front panel of their main chassis for indicating all manner of operating parameters. Both feature a massive amount of power-supply capacitance -- 8000 microfarads, which is enough for a small amplifier. The signal path remains fully balanced, all tube, pure class A and dual mono, with zero feedback -- all of which are nearly religious tenets for Audio Research. The remote control for one will even operate the other.

While the front-panel screens are of a similar size, they are very different. The Reference Anniversary's vacuum-fluorescent screen is for display only, while the Reference 10's color LED display is actually a touch screen that does everything the Reference Anniversary's display does and allows input of commands, giving the user complete control over the preamp and broadening its feature set. All of the remote's commands are duplicated, along with some niceties like the ability to rename inputs and adjust foreground and background color. Want your preamp to honor your home team? Now it can. While the Minnesota Vikings' purple and gold looked nice, I preferred the green and gold of the Green Bay Packers, although for most of my use I went with the Reference Anniversary's green text on a black background because it was easiest to see in my well-lighted listening room.

Inside, the Reference 10 reflects the discovery of new passive parts, including new coupling capacitors, replacing the absolutely immense Teflon ones used in the Reference Anniversary. The tube complement remains the same. Eight 6H30s, the latest breed of dual-triode tubes, reside in the main chassis, providing gain. They were chosen for their higher transconductance and lower noise than the more common 12AU7 or 6922. Two more 6H30s are in the power supply, each driving a single 6550 pentode. It's a bit jarring to peer into a preamp's innards and see what are common amplifier output tubes within. The 6H30s are spec'd for 4000 hours of use and the 6550s for 2000 hours. A built-in time counter makes it easy to follow tube usage and know when replacement is nigh.

The styling mostly echoes classic Audio Research, except for the offset logo, power LED and touch-screen display. The Reference 10 looks sharp -- a further evolution of the classic Audio Research crisp, lab-grade aesthetics. With the Reference 5, Audio Research began offering a pierced-acrylic alternative to the machined-aluminum top cover used for earlier Reference-series preamps. This not only improves sound but also looks better.

The one obvious downside of the Reference 10 (and the Reference Anniversary before it) is its sheer size. Both chassis are wide and deep, requiring their own space -- stacking is impossible, and it's not recommended anyway. If you have a standard four-shelf equipment rack, this means you have to allot half of the shelf space for your preamp, and if you decide you can't live without the companion Reference Phono 10 phono stage (by all reports, one of the finest extant), you will need to buy a second rack. Of course, if you're about to spend such a sum of money on a preamp and phono stage, you are surely willing to buy the necessary support furniture. But just be aware that you may not be able to simply drop one of these products into an existing system.

Beyond this, you'll also need to configure the Reference 10 for your system, renaming inputs to match your source components and indicating if each is single-ended or balanced, as well as adjusting the offset, so overall volume is equalized for each source. This is a welcome feature, especially for doing A/B comparisons, and one that earlier Reference preamps omitted.

Audio Research recommends at least 200 hours of use -- not just "on" time -- before you begin to evaluate critically a new-from-the-box Reference 10, with 500 hours being the threshold for best performance. This seems like a burden -- I don't get 500 hours to listen in a year. However, you can simply connect a thrift-store CD player or FM tuner, set the volume low, and let things simmer. The review unit arrived with a little over 200 hours already on it, with more time added over the subsequent months. While I'm sure the Reference 10's sound would change significantly from 0 to 200 hours, I noticed only slight changes after that point, with the bass taking on a bit more depth and power and the soundstage seeming more lucid and focused.

I've briefly discussed the history of Audio Research preamps, and this is a natural segue to a discussion of what they've historically done in sonic terms. First and foremost are the sheer size of the soundstage and sense of scale they convey. Saying that an Audio Research preamp sounds "big and airy" is an understatement. The soundstage seems to spread in all directions at once, the musicians and singers sounding more life-size and vivid. This is often beyond what even very good tubed competition achieves, and it has been the defining characteristic of Audio Research preamps (and the company's amps, phono stages and CD players as well).

Along with this, Audio Research preamps have handled the bass region well -- beyond what is expected from tubes. Early Reference preamps had very deep and weighty bass for tubes that was also overly ripe, but more recent models, especially the Reference Anniversary, needed no "for tubes" qualification. The Reference Anniversary's bass had state-of-the-art completeness, with tremendous depth and power along with remarkable resolution -- the ability to untangle bass lines and capture small shifts in pitch, as well as display power and slam that made the music felt as much as heard.

The Reference 10 builds on both of these strengths. It has a slightly faster, leaner character than the Reference Anniversary, illuminating the recording's own sense of space even better, and it displays more musically significant detail in the bass region too. Various rock CDs and LPs made this point well, but an even better example came from Suzanne Vega and her wonderful six-disc Close-Up Series set [Amanuensis 2507]. This collects Vega's four Close-Up compilations, each sold separately, and adds a bonus CD of outtakes and a DVD. Aside from it being the least expensive way to buy all of this music (and the only way to get the extra CD and DVD), this is a special collection, and what makes it so is the stripped-down though not necessarily acoustic treatment Vega gives to more than sixty of her songs that span her entire recording career. The sound is special too, with an analog-like sense of ease and unforced resolution. I have to think that Bob Ludwig's mastering of the discs has a role in the truly terrific sound.

There are many, many highlights. I'm particularly fond of the covers from Vega's Nine Objects of Desire, but "Blood Makes Noise," from 99.9 F°, is a great demo track. It opens with a growling, throbbing bass line and what sounds like a synthesized electric guitar, both underscoring the song's title. Vega's voice has some electronic overlay, but it is anchored in the center of an ethereal soundscape that expands into all corners of the room, the bass line powerfully underpinning the song, aided by the low-end power of the Reference 10. This is high-level music-making befitting Vega's intelligent songwriting, the entire package being not just an overview of her work but a worthy addition to her catalogue. While "Blood Makes Noise" is one great cut, there are so many others that are just as engrossing musically and sonically. Great stuff made even greater by the Reference 10.

Midrange dimensionality and density were present and accounted for, though not overt -- in other words, not tubey in the inflated, euphonic sense. Presence was generously maintained, but the mids never drew attention, the Reference 10's keen tonal balance preserved. Voices as diverse as Diana Krall's and Tom Waits' had proportion and character, thanks to the Reference 10's immense resolving powers. It had focus -- the ability to reveal minute detail while never parsing it into irrelevance -- without adding colorations that skew voices toward the throat or chest.

The Reference 10 didn't sound even a bit soft or cloying, as even some modern-day tubed preamps can. Its sound was about truth, though not a severe form of it that's more an ideal than a welcome quality. Dynamics were impressive on both the micro and macro scales, the Reference 10 revealing the tiniest of shifts in inflection from a stringed instrument, then roaring like a jet when the brass let loose. I've mentioned "Fanfare for the Common Man" from the Telarc SACD of Copland and Hindemith compositions [Telarc SACD-60648] in my reviews many times. I also have the CD [Telarc CD-80078] and LP [Telarc DG-10078] of this amazing-sounding recording. It was interesting to compare them all with the Reference 10. The CD sounded spectacular until I played the SACD, whose dynamic range began from a slightly deeper place. The LP couldn't keep up with either digital copy in this regard, but surprisingly the bass drum had more-prominent woody resonance and the tam-tam strikes were more about the attack than the shimmering decay. These are small points to be sure, not the kinds of things we pay close attention to (or even notice) when we're listening purely for pleasure. But the ability of the Reference 10 to reveal them paid dividends up and down the spectrum. While digitally sourced LPs get a deserved bad rap, this one is a digital-to-analog recording done very, very well. It sounded beyond extraordinary with the Reference 10 in the system.

And it emphasized this preamp's greatest and most deserved accolade: its honesty to the signal and to the music, its precision and artfulness. The Reference 10 opens up your music collection, even as some of the qualities I've outlined may seem to make listening a more selective process. This is what great audio equipment does -- puts engineering to work for your enjoyment, not in spite of it -- and it's even more fundamental to the Reference 10 than to any Audio Research preamp that precedes it.

Given that I reviewed the $25,000 Reference Anniversary, I'm sure you want to know more about how that mighty beast stacks up against the Reference 10, which replaced it and occupies the position at the top of the product line, both in terms of ambition and cost.

In my review of the Reference Anniversary, I wrote that it had "an overwhelming sense of composure" and "a sense of calm." Furthermore, "Instrumental and vocal textures were vivid and tangible, imparting a view of the music that was holographic and densely physical at the same time." What this most readily translates to vis-à-vis the Reference 10 is a denser, sweeter character and slightly darker tonal balance. The Reference Anniversary emphasized tangibility and presence. The Reference 10 builds on the considerable strengths of its forebear, sounding lighter, faster, and more resolute, especially in the bass, which was a bona fide strength of the Reference Anniversary and remains so for the Reference 10. If I were using various solid-state amps, I might actually prefer the Reference Anniversary's greater warmth and slightly bloomier bass. However, with any of Audio Research's Reference amps, or amps from VTL or Lamm, I'd choose the Reference 10, because of its more even-handed tonality and better capturing of bass texture and microdynamics.

Right now, a more pertinent comparison is between the Reference 5 SE ($13,000) and Reference 10, given that both are currently available, and until the Reference 10 came along the Reference 5 SE was ARC's top preamp. There are probably some buyers pondering the choice between the two, especially given that the Reference 5 SE has a single chassis and is therefore easier to find room for on the equipment rack.

There is certainly a very similar broad signature at work. That is, lightness, speed, dynamic agility and bass resolution apply to both, but the Reference 5 SE doesn't have the same stop-start suddenness as the Reference 10, and it doesn't dig quite as deeply into the bass. It also shows just how startling the Reference 10's large-scale dynamics are, those tam-tam strikes on "Fanfare for the Common Man" cutting through the air with even greater force and abruptness.

In some respects, the Reference 5 SE splits the differences between the Reference 10 and Reference Anniversary. However, this quick round-robin comparison stays mostly on the level of generalities, so, depending on your personal musical touchstones, you may find that what I outline here is more incomplete than revealing. I would say that (no surprise here) all three of these preamps are broadly similar in sound, but there's no question that the Reference 10 is the most complete and engaging among them.

Willam Johnson passed away in 2011, and I am certain he would be pleased with the current state of his company (I would not say the same for Robert Dunsmuir and what became of his empire). As proof, the Reference 10 is not only a fitting tribute to his much earlier preamps, it's thoroughly modern in function and utterly complete in sound. While one could want a different sonic character in this way or that, this would be an expression of preference, not some universal truth about the Reference 10. Ergonomically, I can't even concede a quibble, as the Reference 10, with its touch-screen display, is more user-friendly and customizable than any preamp I've used, and that includes the Mark Levinson No.32 and VTL TL-7.5, which are very flexible in their own rights.

Audio Research has successfully transitioned to its second generation, and the company continues to add chapters to its story. The long one on preamps can be headed with the Reference 10. It's a preamp for today and for the ages.

Price: $30,000.
Warranty: Three years parts and labor.

Audio Research Corporation
3900 Annapolis Lane North
Plymouth, Minnesota 55447
(763) 577-9700

Associated Equipment

Analog: TW-Acustic Raven AC turntable; Graham B-44 Phantom Series II Supreme and Tri-Planar Mk VII UII tonearms; Denon DL-103R and Dynavector XV-1s (stereo and mono) cartridges; Nordost Frey 2 and Valhalla 2 phono cables; Audio Research Reference Phono 2 SE, Lamm Industries LP1 Signature and LP2.1 phono stages.

Digital: Ayre Acoustics DX-5 "A/V Engine," Halide Design DAC HD, Toshiba Satellite laptop.

Preamplifiers: Audio Research Reference Anniversary and Reference 5 SE.

Power amplifiers: Atma-Sphere MA-2 Mk 3.1, Lamm Industries M1.2 Reference, VTL Siegfried Series II Reference and MB-450 Series III Signature monoblocks; Jeff Rowland Design Group Model 825 stereo amp.

Loudspeakers: Wilson Audio Alexia and Sasha W/P Series 2, Venture Audio Ultimate Reference.

Interconnects: AudioQuest William E. Low Signature, Nordost Valhalla 2, Shunyata Research Zi-Tron Cobra and Anaconda.

Speaker cables: AudioQuest William E. Low Signature, Nordost Valhalla 2, Shunyata Research Zi-Tron Cobra and Anaconda.

Power conditioners: Essential Sound Products The Essence Reference-II, Quantum QB4 and QB8, Quantum Qx4, Shunyata Research Hydra Triton.

Power cords: Essential Sound Products The Essence Reference-II and MusicCord-Pro ES, Nordost Valhalla 2 and Frey 2, Shunyata Research Zi-Tron Cobra.

Equipment rack and platforms: Silent Running Audio Craz² 8 equipment rack and Ohio Class XL Plus² platforms (under Lamm M1.2 amps), Harmonic Resolution Systems M3 isolation bases.