The tubed integrated amplifier is the ne plus ultra of audio. Strong words, those -- fighting words, even. But think it through: The tube integrated is the Platonic ideal of amplification. It’s one box that performs all the required, necessary tasks -- and nothing more.
While it’s true that technology stands still for no man, it seems that every pimply, shining-morning-faced schoolboy with a MacBook seems to think you need to add a DAC to every bloody component in order for it to do anything actually useful. While buying a DAC-in-the-amp might be reasonable if you plan to upgrade next year, I’m firmly against locking today’s computing technology into a product you might want to use for a few years, and doubly against it when considering an audio component of reference quality (and high price). Digital technology changes so rapidly that it just doesn’t make sense to incorporate it into an expensive amp or preamp that you might actually want to keep.
However, the DACless tubed integrated amp has stood the test of time. It’s been in production more than 60 years, and a significant number of those early amps are still making music today. A Dynaco Stereo 70 is still a competent music maker today, with no excuses required for its age.
Audio Research knows something about making long-lasting, good-sounding, rugged gear. Founded in 1970, ARC has been making audio products for nearly as long as I’ve been alive, and though they’re now owned by the Fine Sounds Group, they still will service any and every unit they’ve ever made. Although ARC has since branched out a fair bit, they built their reputation on tubed amps, preamps, and integrateds. While it’s true that ARC has introduced a new preamp, the DSpre, that does include a DAC, their core products remain single-purpose, tubed units. My VT100 Mk.I power amp has been in constant use in my system for over a decade, and is on its second set of power tubes. It’s never so much as burped, and still sounds fantastic.
Audio Research is constantly innovating. I glance at their website every once in a while, to keep track of upcoming new products, and the VSi75 tubed integrated amp ($8000 USD) caught my eye. It took a fair bit of wrangling to propel a review sample across the Canadian border -- international shipping is always a little tricky -- but eventually the UPS truck disgorged a large, white box in front of my house.
Decanting a new component is rarely exciting or glamorous, but removing the VSi75 from its carton was instructive. ARC’s packaging is of high quality, and laid out in a sensible, logical manner. The box is double-layered, and the foam is resilient and thick. I’d have no worries shipping this amp. All manufacturers should package this well.
Once I’d gotten the VSi75 out of its box, I used the included cotton gloves to install its six tubes without getting them grubby and oily. The amp itself is finished in brushed aluminum, so I didn’t feel the need to use the gloves while moving it around.
The VSi75 is a serious hunk of metal measuring 14.5”W x 9.25”H x 17”D -- it feels significantly denser than its 36.4 pounds. Given that its case is made of not-ridiculously-thick aluminum and its transformer cover is perforated, it’s reasonable to assume that most of the VSi75’s weight is in those transformers, as it should be. Tube amps are all about the transformers; the rest of the infrastructure surrounding those transformers is essentially of the supporting kind.
A peek inside reveals design overkill. The circuit-board traces are almost absurdly fat, suggesting unimpeded current flow and long-term reliability. (My Audio Research VT100 Mk.I is similarly constructed.) There’s an industrial flair to the VSi75’s innards -- they don’t have a jewelry-like feel. Rather, the circuitry -- the whole amp, for that matter -- feels like something you might find in a missile silo in Nebraska: solid, rugged, no-nonsense, built to last.
Like its little brother, the VSi60, the VSi75 has two matched pairs of KT120 power output tubes, two 6H30 driver tubes, solid-state regulation, and a JFET input stage. The VSi75 is single-ended only, so all five inputs are RCAs. It also has a tape output, should you wish to fire up the old reel-to-reel. Conspicuous for its absence is a fixed-level input for home-theater use. I use my main listening room for a theater as well, and my trusty Sonic Frontiers SFL-2 preamp also lacks HT pass-through. I’d love to be able to just flip a switch and not have to worry about whether I’ve set the volume right for home theater. First-world problems . . .
Like any self-respecting integrated of this decade, the VSi75 comes with a remote control. This one is a heavy bar of aluminum (it feels cast) that duplicates all of the front-panel buttons: Power, Mute, Volume Down, Volume Up, Bias, and Input. I used only the remote -- the front-panel buttons are uniform in size and color, and their labels are small and not easy for my aging eyes to read. The remote responded well, usually needing only to be vaguely waved in the amp’s general direction.
The VSi75’s small screen displays the volume level in extremely small steps. According to ARC, this digitally controlled “analog volume control” comprises an array of resistors controlled via relays. When the VSi75 is turned on, its display counts down 40 seconds of warmup. Then it fully boots, with Mute engaged and volume set to “0.” To operate the amp, unmute it and raise the volume to the desired level. (I’d prefer that an amp default to the last volume level used.) While the volume control responds rapidly when its button is held down, it’s a very slightly fussy prospect that I never warmed up to. That said, I can see why ARC does it this way -- better safe than sorry, right?
Biasing the tubes couldn’t be easier. Using the remote or the front panel, press Bias and the front panel reads out the level of Tube No.1. Reach in with the supplied screwdriver and twist the trim pot corresponding to that tube until you get to 65mA. Press Bias again and move on to Tube No.2. Repeat twice more and you’re done. I tweaked the amp when I received it (it was off by only 1 or 2mA), and checked it once or twice throughout the review period, but never had to adjust it again. Easy peasy.
For power output, the VSi75 uses the fairly new KT120 tube -- essentially a KT88 fed growth hormone. The KT120 is bigger, stronger, draws a little more current than the old KT88, and can chug out a good bit more power than can the KT88 or the 6550. Hence the sturdy 75W from each pair of KT120s, compared to around 60W or so from a pair of KT88s. The KT120s feel much more substantial in the hand than the 6550s in my VT100. According to David Gordon, ARC’s managing director of sales, the VSi75 didn’t need beefing up to accommodate the brute-like KT120s; that makes sense, given ARC’s propensity to build their products to last.
When the VSi75 was shipped from Minnesota, I corresponded with Gordon, who requested, in no uncertain terms, that I be sure to set up the amp with its supplied power cord plugged directly into the wall, and resting on its own feet rather than on any aftermarket supports. Fair enough, I thought.
“Also,” added Gordon, “make certain that you give it a good 150 hours of break-in time. It might sound a little harsh up to that point.” The review sample already had some hours on it, so it essentially needed another solid week of run-in.
I’ve heard these break-in warnings before, but I generally ignore them -- I have yet to hear a component’s sound change enough over a review period to be audible. So I plugged the VSi75 into the wall using their beefy but otherwise unremarkable power cord and sat back for a listen. My first impressions were troubling. The sound was bright and etched, without much bottom end -- not the sort of sound that endears itself to me. But I remembered what Gordon had said, and rather than jump to any conclusions, I left the VSi75 switched on, stuck a CD in my HD DVD player, and left it on repeat, electricity bill be damned. Fortunately, the VSi75 has a built-in hour meter, so I could keep track of things. I sealed off the basement for a week and checked in periodically.
I also took this opportunity to secure the loan of a Blue Circle Audio BC703NB phono stage. I was troubled by the lean sound of my system with the VSi75, and was a little concerned that my Aqvox Phono 2 CI balanced phono stage wasn’t playing nice with the single-ended ARC. Gilbert Yeung of Blue Circle loaned me a BC703NB, which just smoked the Aqvox -- as well it should, given that it costs nearly four times as much. Anyway, while the BC703NB sounded worlds better than the Aqvox, the system’s lean sound wasn’t the fault of the phono stage. The basic nature of the sound remained the same. The ARC simply needed some more time on it.
After the requisite burn-in, things sounded much, much better. That initial brightness and etch were replaced by a calm honesty and a subtle feeling of power and heft. Greatly relieved and encouraged, I reached into my pile of acid-test sharp-edged rock albums and hoisted out Frank Zappa’s Sleep Dirt (LP, Discreet DSK 2292). The album is crisply recorded and full of jangly but not distorted guitars. It’s a tough listen at the best of times, and if a component veers toward the bright side of the road, it’s nearly impossible to sit all the way through a side. But when my system (and its one or more guests) gets it right, there’s just so much going on that it’s an absolute delight. The title track features a near-as-dammit acoustic guitar duet (it sounds rather processed to me) with Zappa and James “Bird Legs” Youman trading off smooth, flowing licks. I sat there, rapt, through the track, and then, throughout the listening period, kept returning to listen to it again. I could feel as well as hear fingers sliding up and down the strings, each note distinct, every harmonic clearly delineated from its neighbor. In fact, it didn’t take much more than this one track from this one album to get a close look into the VSi75’s soul. This amplifier provided an astonishingly clear window into the spaces within and between the notes of this music.
I’ve harped on before about the later works from Talk Talk’s catalog -- about the sparse, rich, tension-filled buildup of their songs and the cathartic releases that follow. Well, the VSi75 made me wish my turntable had a repeat function. Spirit of Eden (LP, EMI E1-46977) is one of those rare albums that renders me breathless. It’s packed full of things to hear, and repeated listens reward with new discoveries. “Eden” features Talk Talk’s signature tension, with the guitar building to an aggressive climax, and segues with wonderful power into “Desire.” The VSi75’s wonderful way with space allowed me to hear an absolutely monstrous soundscape that stretched from wall to wall and from front to back. That guitar crescendo evaporated away, leaving me exhausted because I was listening loud -- so loud that it had to be near the limit of safety. That’s how this album should be listened to, and that’s how the VSi75 was telling me to play it. I could feel that insistent electric guitar rasping at my bones, digging in, almost hurting me, yet I knew it was going to end suddenly enough and soon enough that I could not only tolerate but actually revel in it. The VSi75 made that guitar into an instrument of torture and love.
There was no midrange or treble glare, no dryness in the VSi75’s sound, no overt euphonic sweetening. The tubed nature of the VSi75’s sound came clearly across in the top registers. Lee Harris’s ride cymbal is prominent in all of Talk Talk’s music, and there was an endearing silkiness to its sound via the VSi75, a texture that didn’t push past reality to become a caricature of itself.
At the start of “Desire” there’s a low-bass rumble and some kind of bowed sheet-metal infrasonic bass that I’d never noticed before, overlaid by Harris’s snazzy muted snare. This is true deep bass, and my Focus Audio FP 90 BE speakers can dish it out, given the right amp. The VSi75 and its artillery-shell KT120 tubes dispensed bass that was tight, tuneful, and just plain old in charge. This wasn’t the kind of soggy tube bass you expect to hear from your daddy’s Dynaco Stereo 70. In fact, it was in the very bottom end that the VSi75 differentiated itself from most of its tubed brethren. Supple, tight, and quick, with absolutely no overhang, the VSi75’s bass most definitely didn’t sound as if it was coming from a tubed integrated amplifier.
Wallowing in an extended Talk Talk jag is like suffering through a bad teenage breakup. It’s chock-full of emotions -- the happy memories, the pain of separation. It’s a hard, deep hole out of which to dig myself, and who better to hand me a shovel than Tom Waits? I wrote about his Mule Variations (Epitaph/Anti- 86547) almost 13 years ago, and I still listen to that same copy today. I can’t help but laugh at Waits’s Bukowski-inspired lyrics, incredibly obvious and oh, so fun. “I woke up this morning with cold water,” he grumbles, before launching into a tirade detailing the miseries of living on the streets. “I’m reading the Bible by a 40W bulb,” he moans. Extremely entertaining.
The VSi75 ran that fine line between having no sound and embodying just a tiny bit of tube glory. It was there, but I had to hunt for it. Check out Marc Ribot’s searing, monstrous guitar solo in “Cold Water.” The VSi75 planted it firmly in my face, with Ribot’s hum and edge-of-the-cliff feedback, sounding like barely restrained anger, curling my nostril hairs. But deep within the music, the VSi75 injected that humanity that only tubes can. Saved from sterility by that inner light and the floating harmonics that accompany it, this solo inspires and entertains. A lesser amplifier would miss out on the wry humor buried deep in Ribot’s playing, but the VSi75 promoted it from becoming simply another guitar.
Compared to what?
Sitting in front of me as I type this is the unicorn of integrated amplifiers. The ARC VSi75 is a tube amp that doesn’t overtly sound like one. In comparison to Focus Audio’s Liszt Sonata ($12,000), which I had on hand to use with Focus’s FP 90 BE speakers, the VSi75 sounded truer to the original signal: less overtly lush, more honest. Listening via the Liszt Sonata to side 1 of Astor Piazzolla’s Tango: Zero Hour (LP, Pangea PAN-42138), I felt as if I were suspended in warm, rich soup, so juicy did this amp sound. As you may recall if you read my review of the Liszt Sonata, I’m very keen on this type of sound, and could happily live forever with this amp. However, I’m aware that the editorializing of an overtly rich tube amp is not for everyone -- heck, it’s probably not for most audiophiles.
Wrap it up?
I’m fairly certain that most listeners, hunting for the archetypal perfect amplifier, would more than likely be happy with the Audio Research VSi75, given its honest, truthful sound. But the world is far from perfect. I suspect that the VSi75 may not find as many homes as Audio Research would like and that the amp deserves. But despite my best efforts, I suspect that those who might most enjoy this amp might be the least inclined to purchase it.
I can imagine the VSi75 appealing to owners of solid-state gear who are searching for a slightly richer, warmer sound. However, they’ll more than likely flail around, switching between transistor amps, trying to find the one that will inject the right dose of soul into their music. They won’t think to investigate such as the VSi75 because tube amps are unreliable and inaccurate, right? No. No, they’re not. At least, not this one.
Hardcore tube lovers, too, might give the VSi75 short shrift. After all, its sound isn’t exactly lush. It’s got a FET input stage, and it’s solid-state regulated. Probably doesn’t even sound much like a tube amp, right? Wrong again. It sounds like a tube amp: a subtle, honest, articulate one that just so happens to exert an iron grip on the speakers lashed to it.
When I began writing for SoundStage!, Doug Schneider drilled into my head the idea that I should always consider who would want to buy the component under review. Who is the VSi75 for? I think the VSi75 would appeal to a huge cross-section of audiophiles. It so broadly straddles the lines of expectation that it may be its own worst enemy. It’s a tube amp that doesn’t audibly slap you in the face about its configuration. Solid-state lovers would like it. Tube lovers would like it. But where it would hit a home run, I believe, is with two groups: those who would like to try a tube amp but are leery of doing so because of the perceived downsides of tubes, and tube aficionados who might be getting tired of unreliable, soggy-sounding tube amps.
If you’re a member of either group, there’s a good chance that an audition of a well-broken-in ARC VSi75 could save you a lot of trouble.
. . . Jason Thorpe
- Analog source -- Pro-Ject RPM 10 turntable, Roksan Shiraz cartridge
- Digital source -- Logitech Squeezebox Touch
- Phono stages -- Blue Circle Audio BC703NB, Aqvox Phono 2 CI
- Preamplifier -- Sonic Frontiers SFL-2
- Power amplifier -- Audio Research VT100 Mk.I, Anthem Statement M1 monoblocks
- Speakers -- Definitive Technology Mythos STS, Focus Audio FP 90 BE
- Speaker cables -- Nordost Frey
- Interconnects -- Nordost Frey
- Power cords -- Nordost Vishnu, Shunyata Research Taipan
- Power conditioners -- Quantum QBase QB8, Shunyata Research Hydra Model-6
Audio Research VSi75 Integrated Amplifier
Price: $8000 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
Fax: (763) 577-0323