Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click here.
It was sometime around 2004. I’d been flailing around trying to find an appropriate replacement for my aging EAR Yoshino 509 mono tube amplifiers. The EARs had become unreliable to the point where I could no longer trust them in my reference system. Looking for reliability and neutrality, I purchased a Musical Fidelity A300cr amp, and that worked well for a year or so, but I was missing something. After reviewing the Anthem P2 Statement one year later, I ended up buying the review sample, hoping that I’d find peace with this large, powerful solid-state amplifier.
I couldn’t do it. I couldn’t settle myself, couldn’t swear off tubes. I was listening to less and less music, and finding it harder and harder to produce reviews. A friend of mine had just purchased a used Audio Research VT130SE, and I was enraptured by its formidable presence, tight grip, and appropriate hint of richness. I found a similar amp on eBay—a VT100, which generated 100Wpc from a total of eight 6550 tubes.
The auction ended at something like 2:00 a.m. on a weeknight, so I decided on the most I’d be willing to pay, and set up a maximum bid. Here’s where it gets interesting: I was willing to go up to $1500, so I thought I put that in the requisite form. But I didn’t. I fat-fingered it—I typed $15,000, hit Submit, and went to sleep.
The next morning, I woke up and discovered—no surprise—that I was the winner. Bidding had ended at $1700, which wasn’t so bad considering how far sideways it could have gone.
The VT100 was everything I had hoped for. It had tons of power, plenty of grip in the bass, a refined top end, and just enough tube richness to renew my love of music. The old girl was a touch fussy, going through two sets of power tubes in the near-decade that I owned it, but I could easily forgive that.
I hadn’t thought about that VT100 in years. I’ve had wonderful amps cycle through my system since it departed: a Bryston 4B Cubed, then a Hegel Music Systems H30A. Other review amps have come and gone, and I’ve been happily listening to mostly solid-state for a bunch of years.
But now! A short while back, I received Audio Research’s new D‑80 amplifier (US$12,950) for review—an all-tube design that’s made me remember just how much I love such things.
The D‑80 is one of six new products that have emerged from Audio Research since its restructuring and subsequent purchase by Valerio Cora, the owner of Acora Acoustics (the Canadian company that’s famous for its speakers with cabinets made from solid slabs of stone).
The genesis of the D‑80 was Audio Research’s desire to build a more affordable version of its Reference 80S (US$18,500), and as such, the D‑80 replaces the company’s VT80SE. It’s a fairly straightforward stereo design, built around two KT150 output tubes per channel. Input tubes are one 6H30 per channel, and the amplifier is hand-built in the US at Audio Research’s Minnesota facility.
In one of my discussions with Cora, I referred to the D‑80 as an 80Wpc amplifier, which seemed reasonable given its model number and the fact that this was the power rating provided on Audio Research’s website. Cora corrected me, stating that Audio Research would prefer it to be thought of as a 70Wpc amp. “The D‑80 will certainly generate 80Wpc, if not more, under ideal conditions—stable line voltage at or above 120V, and with brand-new, matched tubes. Since taking over the company, my policy as CEO has been to rate amplifiers based on real-world conditions under real loads, rather than best-case laboratory scenarios. Viewed through that lens, the D‑80 is consistently and honestly a 70Wpc amp.” However, two days before this review went live, the company’s website still specified the D‑80’s power output at 80Wpc. Cora has told us that the power rating on the site will be updated.
The D‑80 is built on the same platform as the Reference 80S, but Audio Research omitted some features to reduce costs. The more expensive amplifier features the ability to switch between pentode and triode operation. More obviously, the D‑80 doesn’t have the flashy glass front panel of the 80S. The guts are similar though, and the D‑80 uses the same auto-biasing circuit as the Reference 80S.
Visually, the D‑80 is classic Audio Research, with a slab-faced front panel that protects the vertically oriented tubes just behind. If you closed your eyes and pictured an Audio Research amplifier, the image in your mind’s eye would likely be something very similar to the D‑80. The two rack handles on the front add a touch of businesslike authority to the amplifier, and are especially handy when trying to maneuver this 62-pound chunk.
Inputs are via balanced XLR connectors. There are no single-ended inputs, and the D‑80 is fully balanced throughout. While they’re not included, you can use RCA-to-XLR adapters, but I’d imagine most purchasers will use the D‑80 with a fully balanced preamplifier.
The binding posts are good quality, but not extravagant. Interestingly, with four posts per side, there’s provision for 16-ohm speakers in addition to the more usual 4-ohm and 8-ohm connections. The input power connector is a 20A IEC, and Audio Research supplies a beefy, black plastic-covered cord with the amp. That 20A IEC is an important detail, as standard power cords terminated in 15A IEC connectors will not fit. As I didn’t have any 20A IEC power cords, I used the supplied cord for the duration of the review.
Overall construction quality of the D‑80 is excellent. The sides are solid aluminum, the top plate is also thick aluminum, and the well-made steel cover over the transformers does not ring when tapped. The D‑80 comes fitted with a utilitarian—but still somewhat stylish—tube cage that is secured by two screws. It’s an easy on/off procedure, and I left the cage off so I could view those plump KT150s.
The D‑80 exudes strength and solidity, with craftsmanship taking precedence over style. And that’s a style all of its own. In general, the D‑80 evokes the same built-to-last vibe as does my VPI Prime Signature turntable, another proudly made-in-USA industrial product.
Packaging is solid and well-made. The D‑80 ships double-boxed, and the foam inserts are snug and protective.
Startup is intuitive: Hit the power switch at the center of the front panel, and the green LED begins to flash. Once warm-up is complete, the light goes solid green. That warm-up period is quite long—I timed it at a little more than two minutes. Over the course of my review, the D‑80 was operationally invisible. It started up immediately, made no fuss, was silent in use, and warmed up quickly.
As I mentioned in the most recent installment of My Audiophile Neighborhood over on SoundStage! Global, the D‑80 is equipped with a fan that’s tasked with keeping the amp’s voltage regulator at a safe temperature. That fan is somewhat noisy, and my neighbor Ron and I worked with Audio Research to arrive at a solution whereby the fan would only engage if the internal temperature reached a certain threshold. During my use, the fan never engaged. My review sample was an early production model, and all units shipped to dealers will feature this modification.
For the duration of the review, I fed the D‑80 from my Simaudio Moon Evolution 740P preamplifier by way of a set of Siltech Royal Single Crown interconnects. Speaker cables alternated between the matching Siltech Royal Single Crowns and Crystal Cable Art Series Monets. Speakers were the same Bowers & Wilkins 805 D4 Signature standmounts I’ve been using since they landed in my room last year.
When I first hooked up the D‑80 to the 805s, I used the 4-ohm taps. I had eyeballed our measurements of the 805 D4, and these showed some impedance dips that looked like they would be better served by the lower-impedance connection. That said, the 805s sounded dull and uninvolving configured that way, and in short order I swapped over to the 8-ohm taps and never looked back. The D‑80 was commendably silent. With the Simaudio set to a reasonable listening level and the music paused, I could hear absolutely no hiss from the 805s, even with my ear pressed right up against the drivers.
Juice it up
I had both expectations and hopes for the D‑80. Like I said, it had been a while since I’d had a tube power amp in my system. Audio Research has been making tubed components for 55 years, so I expected flawless operation and competent sound quality. Those were my expectations, and (no surprise) the D‑80 delivered. No burps, no hiccups. Over my time with the D‑80 it just plain worked, which is always the expectation, but nothing is guaranteed in audio. Silent, solid, consistent. Those boxes were ticked.
My hopes? I was greatly looking forward to a tube holiday—to relax into a warm bath of Dionysian luxury. Tube amps have a sound. That’s another expectation. Smooth, warm, slightly rich, maybe a bit loose in the bass and maybe a touch sparkly on top, right? Well, not so much with this guy. My first impression of the D‑80 was my first and only surprise. I unplugged my Hegel H30A solid-state arc welder, plugged in the all-tube D‑80, and on first listen, the two amps were more alike than they were different. More than any other quality, the D‑80 exuded neutrality.
One of the first albums I played after hooking up the D‑80 was Rain Tree Crow (16-bit/44.1kHz FLAC, Virgin Records / Qobuz), from the group of the same name. This atmospheric album, loaded up with David Sylvian on vocals, could easily be considered as a reprise to Japan, the early 1980s group that was also fronted by Sylvian. It’s a spacious dreamscape, one that’s easy to sink into. That first listening experience was satisfying. I got the large, billowing images from the backing instruments, with Sylvian’s tight, defined vocals layered coherently over top. The bass, most notably Mick Karn’s delicate fretless noodling, was tight and clear in both its extension and definition. There was no slop here. In all, this album sounded like it should, and made for a perfect, if uninformative start to the review period.
Over the next few weeks, I’d unconsciously find myself returning to albums with the same vibe as Rain Tree Crow. As I’ve mentioned in the past, rather than using any sort of logical auditioning protocol, I let a component pull me around and let it show itself to me. And part of this process is letting the component choose the music I’ll listen to.
I first became aware of Sofia Rei through her live performance with John Zorn, Mike Patton, and Jesse Harris. I strongly suggest you watch this entire concert on YouTube—it’s magnificent. Anyway, Rei has a lovely voice: clear, pure, and full of baroque flourishes. As I listened to The Book Beri’ah, Vol 1: Keter (16/44.1 FLAC, Tzadik / Qobuz), which features Rei with JC Maillard on saz bass, I found myself settling in to the delightful interplay between Rei’s vocal acrobatics and the tabla and other percussion instrumentation. The D‑80 continued to sound neutral, essentially doing a disappearing act. But wait! Slowly, gently, the D‑80 began to reveal a more delicate side.
It began with the cascading overtones on the wiry guitar in “Ge’ulah.” Ostensibly, the D‑80 did that only-the-gain thing, but listening to this track again, I noted how those overtones seemed to wind their way around Rei’s voice. I began to notice how the strings sounded more distinct, each note standing alone, highlighted slightly in space. From the midrange up into the lower treble, the D‑80 extracted an additional sense of dimensionality from the instruments—especially the guitar.
I hesitate to use the term texture, but I think I’m going to have to. My hesitation stems from the association with additive artifacts. The more tube-like an amplifier, the more I think it’s adding information that isn’t there. That doesn’t mean I disapprove, because hell yeah, I sure do like that effect. But I am also willing to acknowledge that the burnished glow that tube amps can add isn’t exactly neutral. A hi-rez photograph of a landscape is a more accurate representation than an oil painting of the same scene. No question there. But the texture that oils add to an image has its own charm, and can evoke more of an emotional response. Tubes can add a dimensional layer that’s the aural equivalent of running your hands or eyes over paint applied to a canvas.
There are degrees of this, obviously. And the D‑80 is extremely judicious in its application of aural texture. That’s why I didn’t notice it at first, instead finding myself focusing on the amp’s essentially neutral presentation.
It’s there, though. The D‑80 is a clever amplifier—it keeps the midrange free of congestion, of any kind of coloration that might lead you to say, “Hey! Those are tubes making that sound!” At first, I had to hunt for that tube sound. I could find it on Marc Ribot’s Silent Movies (16/44.1 FLAC, Pi Recordings / Qobuz), where a simple, unprocessed electric guitar quietly noodles away in a big, empty room. The D‑80 kept Ribot’s guitar tightly focused; crisp and distinct, without any additional warmth. But I could easily flip my attention and note how the amp’s rendering of each brush of the strings was dimensionally complete.
On the very odd occasion, the D‑80 sounded just a tiny bit loose in the upper treble. It took a specific type of music to generate this effect. When I cranked up “Do You Love Me?” by Nick Cave & the Bad Seeds, from Let Love In (16/44.1 FLAC, Mute BMG / Qobuz), the highs became slightly congested and dirty. Not extremely, but noticeably. Admittedly, playing this track through the B&W 805s (which have a treble rise) is an edge case, given that it’s possibly the most abrasive song ever recorded. Still, it seemed like the D‑80 was losing a bit of control over the highs under this assault. This didn’t result in harsh distortion; it was actually quite listenable. Over the duration of the review period, “Do You Love Me?” was the only track that triggered this behavior.
The D‑80 is an imaging monster. Sticking with Silent Movies, I found myself drawn into the contrast between the solidity of Ribot’s bass strings—the rhythm notes he sets up with his thumb—and his fingerpicked melody. On “Fat Man Blues,” he keeps up a loping, train-ride rhythm, and I could almost see the interplay between those two actions.
Same goes for voices. Slint’s Spiderland (Remastered) (24/44.1 FLAC, Touch and Go Records / Qobuz) is far from an audiophile recording. It makes its impact via pure fury disguised as coherent noise. “Breadcrumb Trail” begins with crunching guitar that filled the entire front of my room, but Brian McMahan mumbles away throughout the introduction. The D‑80 pinpointed his position, integrating his storytelling, making it feel more like a part of the actual tapestry of the song rather than just a tacked-on afterthought.
The D‑80’s 70 watts per channel were plenty for my listening habits. I like to listen loud, but at no point did I feel like I needed more power. In fact, the D‑80 was a champ at portraying dynamic contrasts, going from a whisper to a howl in nothing flat. As a result, I didn’t have to listen quite as loud as I usually do in order to get the same effect, the same impact. “Dissidents,” from Thomas Dolby’s The Flat Earth (Collector’s Edition) (16/44.1 FLAC, Echo / Qobuz) is a dynamic buffet, with the opening bass line just snapping out of the speakers. The D‑80 took that bass line and seemed to accentuate it, emphasizing the rise, the attack, and the quick fall on the downside, much more so than I’m used to. Adding to this dynamic prowess was the D‑80’s silence, its lack of hiss and hum. But more than that, quiet passages seemed more delicately rendered, lower in volume—like they didn’t have to fight with the background ambience of the room.
A bit more on Spiderland and the D‑80’s presentation. This is a massive album, redolent with emotion and tension, and it’s full of dynamic swings, going from quiet grumbling to symphonic-level attack in an instant. I’ve told you so far what the D‑80 does, but not how I feel about it. Listening to “Washer,” having it heave itself over me like a fast incoming tide, I just loved how the D‑80 did, well, everything. Tight, bottomless bass; crisp, unfatiguing highs; and a quick, expressive midrange. Couple in the superb front-to-back layering of the soundstage, and the D‑80 drew me in to the exclusion of all else, and made concentrating on writing this review exceptionally difficult.
I needed a break after being battered about the head and neck by Spiderland, so I told Roon to play The Chopin Project (24/96 FLAC, Mercury Classics / Qobuz), an old-meets-new slice of pure tranquility by Ólafur Arnalds and Alice Sara Ott. Piano mixed with violin and synth washes sounds kinda new-age corny, but it works, it works! The front of my room disappeared into buttery, soft-edged fractals, with the D‑80 displaying weight and power on the piano’s low notes, and a delicious sense of dimensionality to the strings. What a pleasure it was to listen to this music through this amplifier.
There we have it
As I spent more and more time listening to the D‑80, I found myself casting side-eye at the Hegel, which sat there looking dusty and abandoned. I still love that big ol’ chunk of steel and silicon, but at odd times I caught myself wondering if the D‑80 wasn’t the better-sounding amplifier—a complete, more musically-satisfying companion to much of the music I love.
Since my old VT100 shit the bed, the thought of actually owning a tube amplifier hasn’t resonated with me. I’ve enjoyed every single one that’s cycled through my system, but I’ve always been aware that they’ve been colored in some way. And besides, I’ve been nervous that if I actually bought one to use as a reference, a) it would break on me and b) it would confound my speaker reviews.
I still think that I’m better off with a solid-state amplifier like the Hegel while I’m writing for SoundStage!. But holy hell, if I only needed to listen for the sheer pleasure of it, I’d jump on this-here Audio Research D‑80 in a heartbeat.
. . . Jason Thorpe
jasont@soundstagenetwork.com
Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click here.
Associated Equipment
- Turntables: VPI Prime Signature, European Audio Team Fortissimo S
- Cartridges: European Audio Team Jo N°8, DS Audio DS 003, Goldring Ethos SE, Ortofon Cadenza Black
- Phono preamplifiers: Aqvox Phono 2 CI, Hegel Music Systems V10, EMM Labs DS‑EQ1, Meitner Audio DS‑EQ2, Mola Mola Lupe
- Preamplifiers: Hegel Music Systems P30A, Meitner Audio Pre, Simaudio Moon Evolution 740P
- Power amplifier: Hegel Music Systems H30A
- Integrated amplifier: Hegel Music Systems H120
- Digital sources: Logitech Squeezebox Touch, Meitner Audio MA3
- Speakers: Focus Audio FP60 BE, Aurelia XO Cerica XL, Totem Acoustic Sky Tower, Bowers & Wilkins 805 D4 Signature
- Subwoofers: Bowers & Wilkins DB2D
- Speaker cables: Siltech Royal Single Crown, Audience Au24 SX, Nordost Tyr 2, Crystal Cable Art Series Monet
- Interconnects: Siltech Royal Single Crown, Audience Au24 SX, Furutech Ag‑16, Nordost Tyr 2, Crystal Cable Diamond Series 2
- Power cords: Siltech Royal Single Crown, Audience FrontRow, Nordost Vishnu, Audioquest Thunder
- Power conditioners: Quantum QBase QB8 Mk II, Audioquest Niagara 5000
- Accessories: Little Fwend tonearm lift, VPI Cyclone record-cleaning machine
Audio Research D‑80 stereo amplifier
Price: US$12,950
Warranty: Three years, parts and labor (with registration); 90 days on tubes
Audio Research
6655 Wedgwood Rd N Suite 115
Maple Grove, MN 55311
Phone: (763) 577-9700
Website: www.audioresearch.com
Email: service@audioresearch.com
