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Equipment Review
February 2005

DK Design Group VS.1 Reference Mk II Integrated Amplifier

by Doug Schneider

"A well-built, great-sounding integrated amplifier that belies its asking price."


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Review Summary
Sound "A gutsy, full and weighty presentation"; "its bass is solid, controlled, and ideally extended, creating a rock-solid foundation for the music." "The highs have excellent extension with a precise delivery, which helps the VS.1 sound quick and nimble." "The mids helped the VS.1 sound grand, with a slightly warm tone and harmonic richness that will please audiophiles who enjoy electronics that have a bit of character."
Features "A massive, almost overbuilt, remote-controlled behemoth with a tube-based line-stage section and a high-power solid-state power-amplifier section" that is said "to output a hefty 160Wpc into 8 ohms and 320Wpc into 4 ohms." "Yes, the VS.1 Reference Mk II has a phono stage for the vinyl lovers who are still in abundance among us."
Use The VS.1 Reference Mk II's front-mounted meter doesn't track output power, but instead the input signal. "The VS.1 Reference Mk II sounded pretty good straight out of its box, but it did enjoy warm-up time, not just when brand new, but each time I pushed Standby to turn it on."
Value "The VS.1 Reference Mk. II's extraordinary build quality and exceptional sonics make it one of the conspicuous values in audio today."

I’ve long admired the common sense and convenience intrinsic to integrated amplifiers. In contrast to separates, these single-box solutions can be a much more economical path to high-quality sound and still allow you to keep your listening room uncluttered.

Unfortunately, although there are a some admirable exceptions -- models from Mark Levinson, Krell, Simaudio, BAT, Rowland, and a few of the British brands like Arcam -- the integrated amplifier is often seen as an "entry-level" product, targeted at budget-conscious audiophiles and not those searching for a taste of the best. An integrated is what you start out with, not what you aspire to. Added to that stigma is the fact that, with a few exceptions, integrateds are not often very powerful or very well built. Power ratings rarely exceed 100Wpc, and far too many integrateds are somewhat flimsy units with stamped-out chassis and plasticky little buttons.

Enter the VS.1 Reference Mk II from the US-based DK Design Group, which certainly has the potential to shake up the status quo. It’s a massive, almost overbuilt, remote-controlled behemoth with a tube-based line-stage section and a high-power solid-state power-amplifier section. At $2995 USD, the VS.1's price places it squarely between the budget end and some higher-priced integrated amps that cost thousands more and whose build quality is comparable.

In fact, the VS.1 Reference Mk II has such broad appeal that it might make bargain hunters think about "stepping up" and might cause some less-cost-conscious audiophiles to reconsider how much they should spend on separates.


I’d seen pictures of the VS.1 Reference Mk II before the unit arrived, but they didn’t prepare me for the huge box that showed up on my doorstep. I cracked it open, looked at the amount of metal inside, slid the box around the floor just to get a feel for it, and said out loud, "Oh, man, this is going to be heavy. Honey, can you give me a hand for a second?"

The VS.1 Reference Mk II weighs in at more than 80 pounds. The chassis is made of thick, thick metal -- the kind of stuff that you find on much pricier gear -- and the faceplate and heatsinks are rock solid. The workmanship and materials wouldn’t be out of place for a product two or three times the VS.1’s price. Even Krell -- a company known for massive, overbuilt products -- with their own high-output (200Wpc), high-value ($2500) KAV-400xi integrated amplifier can’t play the size game with DK Design. The ‘400xi weighs in at a paltry 36 pounds, about half of what the VS.1 does. While sound quality certainly doesn’t correlate with weight, I’m pointing out the VS.1's bulk because some audiophiles derive some comfort from getting mass for their money. In that regard, I know of no product near the VS.1’s price that comes close to it.

The connections on the back are sturdy and of good quality -- no surprise given the heft of the chassis. The topmost connectors are the speaker binding posts. Near the bottom and to the right is the IEC power-cord receptacle, and immediately to its left is the master on/off switch. On the left-hand side are all the line-level inputs, with the left-most one being the phono-stage input. Yes, the VS.1 Reference Mk II has a phono stage for the vinyl lovers who are still in abundance among us. (Unfortunately, I’m not really one of them, so I won’t be commenting on the sound of it.) Right of the phono input is AUX1 and, not surprisingly, AUX2 then AUX3. Below and to the left of the single-ended line-level inputs is a single set of XLR inputs; however, the VS.1 Reference Mk II is not a fully balanced design. For best sound, DK Design recommends using the RCA inputs: "With the RCA connection, the sound is a little bit more dynamic and has more presence." Finally, to the right of the single-ended line-level inputs are a pair of preamp output jacks if, for example, you have a powered subwoofer or some other reason to make use of the line-level signal.

The front panel is sleekly designed with a decidedly Levinson-esque look to it. On the front panel’s bottom left is the Standby/On button. This is used for day-to-day powering-up of the VS.1 once the master on/off switch is turned on. The large middle button is the volume control, and to its right is the input selector. These three controls are also available on the included remote, which, by the way, is very nicely made too -- all metal and heavy, but not too heavy to be cumbersome. It comes packaged in its own snappy case, replete with chic red lining.

Functionally and aesthetically I like the VS.1 -- a lot! -- but I have one issue that's worth mentioning. It concerns the meter that sprawls across the front panel. To start, not many components today have meters, and its inclusion on the VS.1 is not a bad thing, just a sign of a different aesthetic. The issue, though, is its purpose. You may think it’s a power meter -- particularly because it has power-output figures that seem to correlate with the output of the amplifier. But it doesn't indicate the power output, or even an average of it.

I realized this the first moment I played some music through the VS.1. As the music played, the left- and right-channel "needles" (lights really) starting bobbing to the music, roughly between 75 and 100Wpc. That seemed like quite a bit of power, given that the music was not very loud. I then turned the volume down to nothing -- the sound stopped, but the needles stayed in the same area. I then ramped the volume up, and again the needles stayed bobbing in the same area. At first I thought the meter was broken. Then I started fiddling with the Benchmark Media DAC1, which has its own volume control. Much to my surprise, the DAC1 was having an effect on the meter’s needles -- shifting the range upward and downward depending on whether I increased or decreased the volume. It didn’t take me long to figure out that the meter wasn’t tracking the output power at all, but rather, the input signal!

Why? I don’t know.

As I discovered, however, the meter does have one useful purpose. When you press the Standby/On button there’s a delay of about 20 seconds before the amplifier actually clicks on and is ready to use -- the tubes are pre-heating during this time. The two needles, which are pegged to the lowest position at that moment, flash until the VS.1 is ready to use, when they turn solid. So the meter is more or less a glorified on/off indicator.

The VS.1 Reference Mk II is claimed to output a hefty 160Wpc into 8 ohms and 320Wpc into 4 ohms via bipolar output devices. (DK Design didn't have an additional sample available to ship to our measurement lab in California, and they declined to ship the review unit, which was in Canada, there as well.) The company indicates "Pure Class A" operation for both the preamplifier and amplifier stages, but I seriously doubt that this would mean up to full power for the amplifier stage. Amps that run in pure class A up to full power are usually very large (yes, the VS.1 Reference Mk II is big) and operate extremely hot (which the VS.1 Reference Mk II doesn’t). My old Blue Circle BC2 mono amps claimed pure-class-A operation, and, boy, oh boy, did they run hot. They were only rated at 75Wpc. I’m not exaggerating when I say that they could heat up my room in the winter. The VS.1 runs from warm to a bit hot, but nowhere near as toasty as the BC2s did.

The tube-based preamplifier section qualifies the VS.1 as a "hybrid." It ships with 6922 tubes from China. Daniel Khesin, undoubtedly the D and K of DK Design Group, encourages tube-rolling, which I purposely didn’t do for this review for the simple reason that I feel this initial review should be of the product as shipped, as is. But, according to Daniel, "Early 1960s Siemens CCA tubes give the amplifier the best dynamics, slam, rhythm and pace, along with a very transparent and detailed presentation. The Mullard CV2492 (British version of the CCA) will sound completely different, with a very luscious, palpable, and three-dimensional midrange, although not quite as dynamic or detailed in the high frequencies."

Finally, it’s worth mentioning three more things. First, VS.1 Reference Mk II comes with a five-year warranty. Second, it’s shipped in a sturdy cardboard box with plastic-lined handles cut out on the sides. That may seem like a small thing, but the handles make hauling this beast around somewhat easier. Third, the VS.1 Reference Mk II comes with a very nicely finished interconnect cable with some beefy, well-made connectors. I didn’t use this cable in my evaluation simply because it was too short for what I need between my DAC and the integrated, but I do like the fact that DK Design Group included it. It is just one more touch in what’s altogether a well-thought-out, high-bang-for-the-buck package.


The VS.1 Reference Mk II turned out to be a spot-on match for the MB Quart Vera VS 1F loudspeakers I had in for review at the same time. These outstanding floorstanding speakers don’t necessarily need high power, but if they have it, they can provide a wonderfully transparent, neutral-as-anything performance at low, medium, and especially ear-splitting volume levels. With the VS.1’s seemingly ample power reserves behind them, the MB Quarts soared.

Other equipment in the mix was my Theta Data Basic transport fronting the Benchmark Media DAC1 and Stello DA220 DACs, both of which I reviewed last year. i2Digital’s X-60 provided the digital link from the transport to the DAC, while Nordost Quattro Fil was used for the analog link from DAC to the VS.1. Speaker cables were rather generic in order to work with the MB Quart speakers’ unique binding posts. All this was played in my large listening room, measuring more than 19"W x 34'L.

The VS.1 Reference Mk II sounded pretty good straight out of its box, but it did enjoy warm-up time, not just when brand new, but each time I pushed Standby to turn it on. This point was driven home when I went from a preamp/amp combo that I’m also reviewing back to the VS.1. After this switch, the VS.1 sounded slightly edgy, which bothered me because I didn’t recall it sounding like that at all before I took it out of my system. However, I let the VS.1 play some music and "cook," and within 20 minutes or so the edge was gone and the sound was back to normal. Moral of the story: Don’t evaluate a "cold" VS.1 Reference Mk II or you won’t be hearing what it really sounds like.


The warmed-up VS.1 has a gutsy, full and weighty presentation -- it has heft, but not too much, and it is certainly not lean- or light-sounding in any way. Its bass is solid, controlled, and ideally extended, creating a rock-solid floor for the music. The VS.1 had no trouble controlling the Vera VS 1Fs, even at the most stupidly high volume levels. I played the 25th-anniversary version of The Clash’s London Calling [Epic/Legacy 92923] at near-stadium levels, and neither the amp nor the speakers broke a sweat. But this isn’t just a high-power integrated amp suitable for parties and PA systems; it’s refined-sounding, too, which is what you’d expect from an integrated amplifier with an audiophile pedigree.

The highs have excellent extension with precise delivery, which helps the VS.1 sound quick and nimble. I can’t say that the VS.1 is as pristine up top as the very best electronics I've heard. I found that the VS.1 isn’t as feathery in the highs when I put it head-to-head with the much more expensive Song Audio SA-1/Stello M200 combination I have set up, but the VS.1 doesn’t cost nearly what that duo does. For $3000, the VS.1’s treble performance is remarkably good.

The midrange, probably the real selling feature to many audiophiles, particularly those who enjoy the sound of tubes, has great clarity along with richness and vibrancy that makes voices and instruments that hover in this region sound very real. Here I had no quibbles -- the mids helped the VS.1 sound grand, with a slightly warm tone and harmonic richness that will please audiophiles who enjoy electronics that have a bit of character, as opposed to products that sound rather clinical and lifeless. In fact, I found myself turning to quite a few vocal-dominated recordings when reviewing this integrated amp because the VS.1 Reference Mk II sounded so good with voices.

Fiona Apple joins Johnny Cash for "Bridge Over Troubled Water" on American IV: The Man Comes Around [American 063339]. I never thought I’d hear Johnny Cash do this song, let alone with the somewhat oddball Apple, but it’s all there on The Man…, and it’s good. With the VS.1 Reference Mk II, the voices are prominent in the mix and have loads of detail. I played this track from very low to obscenely loud levels, and both the amp and the MB Quart speakers remained remarkably composed, painting an enormous collage of sound that, for lack of a better word, was glorious in every way. Apple and Cash sounded full and round, and they hovered in space, almost in Technicolor. The soundfield was vast, filling the far end of my room. Spectacular? You betcha!

The VS.1’s rather majestic sound also lent itself well to Willie Nelson’s Stardust, which has been decently remastered as part of Columbia/Legacy’s The American Milestones Series [Columbia/Legacy CK 65946]. Like Cash’s latest recordings, the vocals on Stardust are placed up front in the mix. There’s a thereness that you just can’t miss, and I like it. The instruments, which are well delineated and clear, more or less surround Nelson, playing second-fiddle to his voice. It works.

I particularly liked "Georgia on My Mind" played over my system. Nelson’s voice was almost bulbous -- it was so present and well placed, with loads of decay. I was using Stello’s DA220 DAC when I played this track, and despite the DA220's low price, it has a miraculous way with low-level detail. It was a snap to hear the space around Nelson’s voice, giving it a greater sense of dimensionality and a firmer place in space. The cymbals, which are lightly recorded and not so prominent, had a light, airy sound, and were clean and clear. The DA220 retrieves the "air" from the recording spectacularly, and the VS.1 has no trouble passing it along. I was impressed with the overall level of resolution and transparency from this modestly priced integrated amplifier and DAC combination.

The characteristics of the VS.1 Reference Mk II are, obviously, high power -- which is great for driving just about any loudspeaker you throw at it -- overall sonic refinement, and rich, glorious sound, most notably in the midrange, which gives the presentation a touch of pleasant voluptuousness. Bass, which shouldn’t be overlooked, is deep, tight, firm, and punchy when it needs to be. In ways, the sound reminds me of that of my all-tube Blue Circle Audio BC3000 line stage, which I still own, and hybrid BC2 mono amps, which recently went to live out their remaining days at the Blue Circle Museum. All of these electronics, which mix tubes and transistors in interesting ways, combine the strengths of solid-state designs -- respectable power, control, and extension -- with the best-loved attributes of tubes -- warmth, texture, and a slight fullness to the sound -- and make music sound more natural to my ears than what I hear from overly thin- and sterile-sounding electronics.


One integrated amplifier that I use in my review systems from time to time is Zanden Audio’s Model 600, an all-tube design. When I reviewed it in late 2002, it retailed for $4500 -- 50% more than the VS.1. It was designed to be the entry-level product to Zanden Audio’s world -- a world of audio products that nowadays start at just over $10,000.

I like the 600 a lot, and providing it’s not pushed beyond its limits -- it’s rated at 30Wpc -- it can provide an extraordinarily enjoyable listening experience. Still, being a smallish tube integrated amp, it can only do so much. For example, the high-powered VS.1, which has a tube line stage and solid-state output stage, has bass that’s deep, tight, visceral and driving, just as you’d expect. The Model 600’s bass, even at moderate volumes, is reasonably deep and has good but not extraordinary weight. It is, not surprisingly, tube-like in that regard -- full and round, but not immediate and impactful. The 600’s highs are pristine and delicate, nothing I can quibble about, but I suspect not quite as extended as the VS.1’s -- again, often the nature of tube-based designs.

The midrange, however, is where the 600 takes the lead, at least for those looking for that warm, rich sound for which tubes are known. The VS.1 hints at lushness, but the 600 drips with it, and has texture that’s both vivid and rich. Johnny Cash’s close-miked voice on The Man Comes Around doesn’t sound any closer or any more immediate through the 600 than the VS.1, but it does sound slightly more fleshed out and, to use a well-worn audiophile phrase, palpable. For someone who really wants a tubey sound in the mids -- the best aspects of it, not the worst, mind you -- that’s where the 600 shines, providing you don’t need much power and can live with the other limitations of tube-based power.

I can recommend the Model 600 for someone with relatively easy-to-drive speakers and who doesn’t need whomp-it-home bass, reach-for-the-stars highs, or ear-splitting SPL capabilities. The Model 600 isn’t those things, but it has a certain magic to it that makes it quite special, as are all the components I’ve heard in Zanden’s unique family. That said, the 600 is obviously not the integrated amplifier for everyone, and it’s not all that feature-rich either. The Model 600's sonic signature makes it distinct, and is a statement of simplicity and styling elegance, with just an on-off knob, an input selector, a volume control, and no remote control.

On the other hand, the VS.1 Reference Mk. II has far broader appeal, and while not necessarily feature-rich when you compare it to a loaded-up surround-sound receiver, it does have more features than the 600 -- not to mention a remote control, which is more or less standard equipment these days. Also, the VS.1 is built in a way that means business -- serious business -- and its claimed power-output capabilities and ability to drive most speakers make it suitable for just about any setup. For a reviewer, that’s important because it means that a speaker won’t be limited by the amplifier it’s used with. For a consumer, it’s good for similar reasons: you have an amplifier that you can use with most any speaker you may buy today or in the future.

The VS.1 Reference Mk. II is also easy to recommend because of its price, which is eye-opening when you look at the unit on paper, and even more so when you see it in your room. It looks like it should cost $6000, or maybe even more, and in many regards sounds that way, too. In fact, if that’s what the VS.1 Reference Mk II cost, I’d still consider it a good value, although I’d also demand a couple more things -- those "feathery" highs I mentioned earlier, the 600’s scrumptious midrange, and perhaps a couple of features like individual gain adjustment for each input like the twice-the-price Mark Levinson No.383 has. Still, the VS.1 Reference Mk. II's extraordinary build quality and exceptional sonics make it one of the conspicuous values in audio today.


The number of new companies that make a surefooted entrance into the high-end-audio market is a fraction of the number that enter and don’t make a dent. Succeeding requires understanding the market thoroughly and then having the wherewithal to produce attention-grabbing products -- the solvency of the company depends on it. That’s usually the domain of large, well-funded companies, not small startups.

However, I’ve had the pleasure over the years of encountering a few of the early products from noteworthy new companies. A couple of years ago it was Amphion and the outstanding Argon2 speaker, which still holds up against some of the best today. Last year it was Stello and the DA220 DAC -- a product I purchased and use in my reference system. Now there’s the VS.1 Reference Mk II. Some of its charms are industrial, which is to say that it is built to incredibly high standards. Sound-wise, the VS.1 presents a richly vibrant sonic picture that has the earmarks of a solid-state design -- extension high and low, drive, and ample power -- along with hints of the color and musicality for which tubes are known. My quibbles about this integrated amp are small, and they have nothing to do with its performance or build quality, which I feel are so noteworthy that the VS.1 Reference Mk II is what I will gauge other like-priced competitors against.

Every company has to begin somewhere, and for DK Design Group, the VS.1 Reference Mk II is an early winner. It’s a well-built, great-sounding integrated amplifier that belies its asking price. You can certainly ask for more, but you won't likely get it.

...Doug Schneider

DK Design Group VS.1 Reference Mk II Integrated Amplifier
$2995 USD.
Warranty: Five years parts and labor.

DK Design Group Inc.
1983 Markus Avenue, Suite 206
Lake Success, NY 11042
Phone: (646) 485-0754
Fax: (646) 219-2572

Website: www.dkdesigngroup.com

DK Design Group responds:

Thank you for a terrific review of the VS.1 Reference Mk II. We feel that you nailed it when you stated that the VS.1 Reference Mk II has "such broad appeal that it might make bargain hunters think about 'stepping up' and might cause some less-cost-conscious audiophiles to reconsider how much they should spend on separates" -- this was indeed the goal of this product. This integrated amplifier represents an effort to maximize the potential of integrating a super-low-noise vacuum-tube preamp with massively powerful solid-state amplification. This technology holds a lot of promise and if done right can deliver spectacular results that were previously not considered possible at this price point.

We did want to point out that the VS.1 Reference Mk II is extremely sensitive to tube rolling. In our efforts to control costs and bring the unit to market at $2995 we chose a rather generic 6922, a linear and neutral-sounding tube, but a dramatic improvement is possible with a more exotic Siemens, Mullard, or Amperex tube. In your description, you state that the "VS.1 hints at lushness," and this is very accurate. Substituting the stock tubes with a Mullard CV2492 results in a very lush, rich, and holographic presentation in the midrange, although this tube is somewhat soft at the frequency extremes. We highly recommend this tube to customers who crave traditional tube-like sound, or the lushness and liquidity of low-powered tube amps. We have also observed terrific results with the Siemens CCA, Amperex 6922 PQ, and the Reflektor 6H23N-EB. Each of these tubes has a very different sonic presentation and dramatically improves the performance of the VS.1 Reference Mk II. The specific sonic properties of each tube can be used to tailor the sound of the amplifier to match the user’s musical preferences and system. Finally, it is very important to use a reliable tube source since we have been hearing reports of counterfeit NOS tubes labeled as Siemens, when, in fact, they are just re-labeled $2 Chinese tubes.

Again, thank you for your thorough evaluation!

Daniel Khesin
DK Design Group, Inc.

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