Audio Research VTM200 Mono Amplifiers
by Marc Mickelson
The VTM200 monoblocks ($14,990 USD per pair) fall perfectly into the middle of Audio Research's amplifier line. They belong to the company's VT series, which includes the VT50 stereo amplifier reviewed here a while back, but they are monoblocks like the Reference 300 and 600 ($29,990 and $39,990 per pair respectively -- ouch!). The VTM200's chassis is identical to that of the VT100 Mk III, 19"W x 8 3/4"H x 19 1/2"D, making it large but not nearly the size of the Reference-series amps, which were being moved around with engine hoists when I visited Audio Research. The VTM200 is available with standard ARC black or silver faceplates, but in either case the front-mounted handles are always black, adding a nice visual touch and convenience feature for toting around their 74-pound weight.
The only functional items on the VTM200's clean front panel are a power switch and LED. Around back, however, there are a number of features, including all provisions for biasing the output tubes (which I never had to do but is explained well in the user's manual), speaker connections for 4-, 8- and 16-ohm loads, a two-position switch for the amp's internal cooling fan, and a 12V on/off trigger included for custom-installation use. The VTM200 is a completely balanced design and will accept only XLR-terminated interconnects -- "for best sound," as ARC likes to say.
ARC claims for the VTM200's circuit "an input/driver/output combination with incredible linearity and dynamic headroom, having great stability under dynamic conditions and varying speaker loads." Its input stage uses direct-coupled JFETs and is followed by a single 6N1P tube amplifying stage. This in turn is coupled to a pair of triode-connected 6L6GC tubes -- which are used as output tubes in some designs. The VTM200's output stage utilizes six 6550C tubes -- three matched pairs -- and is fed by a power supply with 438 joules of energy storage (for comparison, the power supply of the Reference 300 has 448 joules). Screen voltage for the partially cathode-coupled output stage is supplied by two 6AS7 regulator tubes driven by another 6N1P. Inside, the amplifier is dominated by two massive and heavy transformers and two circuit boards. Of special note (because of the bother required) are the 20 screws used to affix the VTM200's top plate.
Each VTM200 is rated to deliver 200 push-pull watts from 10Hz to 200kHz at no more than 0.5% distortion at full power and below .02% at 1 watt. Interestingly, while many amplifiers today eschew the use of overall negative feedback, the VTM200 uses 12dB. Power requirements are high: 400 watts at idle and 670 watts at rated output -- per amplifier! These are not the amps for audiophiles thinking of going solar.
System and use
I used the VTM200 monoblocks to drive Wilson WATT/Puppy 6 speakers, which don't really need 200 watts to play loudly, but the extra power never hurts. Preamps were the Lamm L2 Reference and Audio Research's own Reference Two Mk II. I used a Mark Levinson No.39 CD player by itself or in conjunction with a Bel Canto DAC1.1 and DH Labs coaxial digital cable. The preamps and DAC sat on sand-filled Target stands, while the amps and CD player rested on Bright Star Big Rocks, the latter with a Townsend Seismic Sink in between.
I was lucky enough to have a few sets of balanced interconnects around for use with the VTM200s. These included JPS Labs Superconductor2, DH Labs Air Matrix and Transparent Reference XL -- matching speaker cables too. I preferred the Transparent cables with the ARC amps, but none of the cables could be considered a poor choice. Power cords were from Shunyata Research (all models), TARA Labs (RSC Air and RSC The One), JPS Labs (Kaptovator), Transparent (Reference PowerLink and PowerLink XL) and ESP (The Essence). However, because the VTM200s need power cords with 20-amp connectors (20-amp circuits are also highly recommended), I could only use the Transparent PowerLink XL 20s, which cost a hefty $1500 each, in the place of the heavy stock cords. Audio Research is proud of the power cords it includes with its products these days, as each is chosen for its sonics. The company even sells these cords to consumers. So if the thought of springing for a pair of high-priced power cords has you shaking your head, ARC has you covered.
The VMT200s are fan cooled. This will increase the life of the all internal components, but it also helps the amps double as space heaters, a benefit during the winter for sure. The VTM200s raised the temperature of my 12' x 24' listening room six degrees, so if you live in warmer climes than the upper Midwest, you may want to make sure your AC is working at its peak when you have these amps in your listening room.
A product of Minnesota
There I was sitting three rows from the PA speakers at a performance of A Prairie Home Companion, Minnesotan Garrison Keillor's long-running radio show replete with Keillor's brand of down-home humor and lots of live music. As I sat there listening, my eyes often closed during the musical numbers, I was impressed with the sound. You may be thinking that any audiophile should be impressed with the sound of live music, but often PA systems in large halls make sonic matters unbearable. I remember a Proclaimers concert years ago at which the sound was so loud and muddy that I couldn't make out any of the words the Reid brothers were singing or speaking. And no, their Scottish brogue wasn't the problem -- the dreadful PA system was.
But this was not the case when I attended A Prairie Home Companion. In most instances, I would have considered myself too close to the PA speakers, but here my proximity made me realize that the sound was truly special. It was utterly clear and immediate, but its impact, that ability of notes to explode into sound, caught my attention. It was what I was hearing from the VTM200 amps I had in my system, but I was loath to describe it as a simple increase in speed or resolution. It was impact that the ARC amps brought to my system -- due to the startling vividness of the music they made.
Does this mean that the VTM200s are perhaps a little too prominent in the upper midrange or treble? This is often the frequency range from which a sense of greater detail and speed comes -- highs that are tipped and emphasize the leading edge of transients. But this is not the case with the VTM200s -- no way. Unlike the highs of some tube amps that I admire, the treble of the VTM200s is not even a little euphonic. It's honest to recordings and the playback chain -- not the source of additional glare or grain, but not hiding it if it's there already either. My CD for testing this is Wayne Kramer's rowdy The Hard Stuff [Epitaph 86447-2], which begs to be played LOUD even with its steely treble that will chase most listeners from the room. The guitars on "Crack in the Universe" seared with the VTM200s, as they should. The ARC amps may use tubes, but they don't prettify recordings; by the same token, they serve what's on each disc, reproducing what's fed to them without editorializing. The VTM200s don't sound like solid-state amps, however, because there is a recognizable bit of tube bloom happening, images seeming to float in very defined space.
Another sonic trait that helps the VTM200s sound impactful is their upper bass, which lends real power and punch to music, especially rock and jazz. It's a little more prominent than what you'll hear from a leaner-sounding amp, especially solid state, but it counters with lots of detail and texture. I loved listening to non-studio recordings with the VTM200s, especially Cowboy Junkies' Whites Off Earth Now [BMG 2380-2-R] and the Columbia Records Radio Hour, Volume 1 sampler [Columbia CK 66466]. Both are live recordings, and they sounded exceptionally so via the VTM200s. Lower in the bass, the VTM200s are very impressive for a tube design, never crapping out like lesser tube amps will but also remaining true to the signal fed to them without any added warmth or excessive weight. The upper bass conveys a sense of power and, again, impact, while the rest of the bass region is unobtrusive and goes plenty low. "Where the Dream Begins," from Tom Russell's newest release Borderland [HighTone HCD8132], displayed far more low-end detail and directionality with the VTM200s driving the Wilson speakers. At slightly higher-than-normal listening levels, I could literally feel the bass in the pit of my stomach.
The VTM200s are soundstaging champs, casting a sonic space that's enormously wide and deep -- beyond even the boundaries of my room. This is aided by the sheer power these amps can deliver -- I doubt there's a speaker made that the VTM200s can't drive to deafening SPLs. And large-scale dynamics? Get outta here -- these amps soar. Back to Whites Off Earth Now and "State Trooper," a cover of the song from Bruce Springsteen's Nebraska. "The band is here," say my notes, "and so is the venue." We reviewers often talk about a speaker taking over a room, but the VTM200s are able to pull off this feat too via their big, tactile sound. In fact, these might be the first amps that were too big for my room! I can even see having to reposition speakers to prevent the bass from turning into a congealed mess due to too much boundary reinforcement and the soundstage from sounding like it's too far forward.
Finally, no review of these amps would be complete without a word or two about their exceedingly low noise floor. Music emerges from very far down in the mix, so each sonic event has a longer duration, imparting the fact that notes, not just individual instruments, have qualities of their own too. Call this microdynamics or what have you, but a perfect example of this is the great JVC XRCD remaster of Wynton Kelly's Piano [Victor VICJ-60259]. Yes, there's a little bit of tape hiss on this 1958 recording, and the VTM200s' fans are not completely silent either, but even with these impediments, the notes of Wynton Kelly's playing spring to life and sustain with great purity and precision. And Milt Jackson's vibraphone on another XRCD, The Modern Jazz Quartet's Django [Victor VICJ-60160], takes forever to fade away, then rings again with each new stroke. You will notice these details with other amps too, but with the VTM200s, they're startling in their vividness, as are musical details of all kinds.
In a nutshell, the VTM200s cast a huge soundstage, are detailed without sounding exaggerated, portray music with clarity and punch, and offer seemingly limitless power. They're powerful amps, and they sound that way. I can't say they walk the line between tubes and solid state as much as they transcend it. If you want the energy of live music in your home, these are your amps.
The power of power
Although both the ARC VTM200s and Lamm ML2s are tubed monoblocks, the similarities end there. The Lamms are 18W single-ended amps -- need I say more? They also cost over double what the VTM200s do. But comparing the two amps puts each in higher relief, showing even more clearly the ways in which each succeeds.
In general, the ML2s offer a more laid-back perspective on the sound that's no less detailed but more full and palpable. This is at the heart of the charm of these amps -- they are detailed yet very natural and organic. And as good as the VTM200s are on transients, the Lamms are very slightly more snappy on the inception, while the VTM200s do decay like no other amp I've heard. The ML2s have more midrange texture, the VTM200s sounding slightly leaner in this region. The Lamms are more poised and their soundstage more distant, although they are not obscure or distant themselves. The VTM200s are more lively and massively powerful. If you get the idea that few listeners would consider both amps for purchase, you're right. The two are sort of like a Bengal tiger and a bald eagle -- both command attention, but for different reasons.
The VTM200s are more about macrodynamics and truth, while the Lamms are about microdynamics and beauty. And this will be the rub for some listeners. While the VTM200s can belt out the sound, they don't captivate in the same way the Lamm ML2s do. They dont involve in the same way. The VTM200s are high-fidelity brutes. Their qualities can make for some spectacular sound, but they won't be the envy of SET enthusiasts, who seemingly hear what others don't. You'll hear everything with the VTM200s -- and how!
Often, as I finish my listening to and thinking about a piece of review equipment, I wonder about its potential buyers. Those for the VTM200s are audiophiles with deep pockets but not bottomless ones (ARC's Reference 300s and 600s are for these) who need lots of tube power but want no concomitant tube lushness. VTM200 owners will be looking for an honest pair of amps that can power even insensitive speakers in a large room, and do so with a kind of vividness that is closer to the nature of live music than other amps whose stock and trade may be greater human involvement with the music. To some extent, it will come down to the old audio debate of honesty versus subjective enjoyment, the VTM200 owner wanting all of the former in service of the latter.
Needless to say, I greatly enjoyed my time with these tubed powerhouses, and if you are considering an amplifier at or above their price -- tube or solid state, even ARC's own Reference-series amps -- you need to hear the VTM200s during your buying tour. The VTM200s are certainly not cheap, but with them you may get more of what you're after sonically and perhaps save some money too, neither of which is a bad thing.
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