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Equipment Review
August 2004

Stello DP200 Digital-to-Analog Converter/Preamplifier

by Tim Shea



"A Swiss Army knife for audiophiles."

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Review Summary
Sound "As it turns out there is more than a little family resemblance in the sonic characteristics between the preamplifier and DAC functions of the DP200" -- "the words that kept coming to mind were 'transparency,' 'detail,' 'refinement,' and 'transparency' again"; when preamp and DAC were used together, "the top and bottom ends of the spectrum maintained their relative strengths, and transparency reigned supreme, again with no apparent loss of tonal expressiveness."
Features Integrated fully balanced, class-A preamp and upsampling DAC with provision for add-on MM/MC phono and analog-to-digital circuit boards; "headphone jack…is fed through the DP200’s primary analog stage rather than incorporating the use of cheap op-amps"; includes home-theater pass-through input; "all the basic controls can be accessed from the front panel or from the included remote control, which, by the way, is of the heavy, metal variety."
Use Can be used as a standalone DAC or preamp, or as a preamp with built-in DAC; fully remote controlled, but no balance control.
Value "That you get all the DP200's flexibility, build quality and astounding performance for less than two large borders on the absurd."

Reviewing audio products from new or relatively unknown manufacturers is a mixed bag. On the one hand there’s no recognized company philosophy or "sound" with which to anchor or relate certain attributes. On the other hand, it’s nice to start with a completely blank slate and let the product, and only the product, take me on a journey to wherever it is capable of transporting me. For reviewers, it doesn’t get much more fun than this, especially when the product is of exceptional quality, in which case we get to feel like explorers travelling to new and exotic lands rather than common travelers taking a generic, overcrowded bus tour.

So it was with the Stello DP200 preamplifier/DAC, with which I found myself in some rather uncharted territory. And what better companion to have with you on a long trip than a Swiss Army knife, which is exactly what I consider the DP200 -- a Swiss Army knife for audiophiles. As it turns out, however, a more analogous product might be the Leatherman. Read on for details.

Description and use

For those of you who may not know (until recently I’d be counted among you), April Music, the parent company of the Stello brand name, has actually been in the audio-electronics business for some time, first as a Korean importer and more recently as a manufacturer. In addition to the DP200 DAC/preamplifier, the subject of this review, April Music also offers a preamplifier, stereo amplifier, CD transport, and standalone DAC (recently reviewed by Doug Schneider), all under the Stello umbrella.

Right off the bat, the folks at April Music made a positive impression as they took the trouble to pack the DP200 in a formidable wooden crate. That they go to such trouble and expense to protect their product indicates to me that a great deal of care went into what’s inside. A positive second impression came about when I removed the DP200 from its wooden womb. The darn thing seemed almost as heavy as my reference amp. The unit itself measures 17"W x 3 3/8"H x 13 3/4"D and weighs in at an SUV-like (for a preamplifier anyway) 20 pounds.

The favorable impressions continued -- aesthetically, the design was as tasteful and clean as a whistle. There are no gold accents or shiny bits, just a nice, straightforward and functional look that's certainly attractive. All the basic controls can be accessed from the front panel or from the included remote control, which, by the way, is of the heavy, metal variety and is very easy to use in practice despite having 26 identically sized buttons. My only criticisms are that you pretty much need to point the remote directly at the unit for it to work, and changing batteries involves a screwdriver. Like the DP200 itself, the remote seems to have been designed for multiple purposes. It can control a preamplifier, DAC and transport, and in all likelihood it could be used for self defense given its formidable weight and solidity.

Upon reading through the manual I learned that the DP200's preamplifier section runs in class A as a dual-mono design and is fully balanced, which is how the manufacturer recommends using the DP200 to extract every last iota of performance (more on this later). As I would find out, in addition to being almost as heavy as my amplifier the DP200 also ran hotter, even when in standby mode, so I guess April Music is not kidding about the class-A thing. Analog input voltage is listed at 1.4V (1.0V balanced) and maximum output voltage is stated as 3.5V.

Around back you’ll find a fairly full complement of ins and outs that will accommodate a wide range of components and connections. There are three sets of analog inputs, including one balanced and two single ended, and these are channeled through one set of balanced and one set of single-ended analog outputs. On the digital front there are four input options: one AES/EBU, two coaxial with RCA jacks, and one TosLink. There are also three digital outputs: AES/EBU, RCA coaxial, and TosLink. The only thing I could think of that was missing was a six-channel analog input for multichannel music. The DP200 is strictly a two-channel affair. However, rounding out the rear connections are a bypass input that allows for connecting the front L/R output from a preamp/processor that circumvents the DP200’s volume control so that the preamp/processor has full control of the volume for home-theater or multichannel operation. I took full advantage of this feature and wish more high-end manufacturers would include it for those of us who cannot have separate home-theater and stereo setups. Also included for convenience is a trigger input to facilitate installation flexibility. Last is a small switch that selects operation of the DP200 as either a standalone DAC or as a preamplifier/DAC combination unit (be sure the power is off before using this switch). If all this weren’t enough, the fine folks at April Music saw fit to include a headphone jack that is fed through the DP200’s primary analog stage rather than incorporating the use of cheap op-amps.

You want more? OK. How about an optional phono board that can take both MM and MC cartridges and employs six gain and six load settings? And just in case you might like to record your precious vinyl for posterity, you can do so with the optional analog-to-digital converter that allows for upsampling to 96kHz if you so desire. The ADC module is said to be of studio quality that rivals or betters the converters installed in most digital recorders, and all recording functions can be controlled via the remote control/home-defense weapon.

Since Doug Schneider recently reviewed the April Music’s DA220 DAC, I’ll keep the description of this functionality short and sweet. The DAC section in the DP200 is basically the same as that in the DA220, which is to say it utilizes a Delta-Sigma DAC configuration and sixth-order digital filter, along with a PLL circuit to address jitter issues. This is an upsampling unit that allows the user to choose 16 bit/48kHz, 24 bit/96kHz, 24 bit/192kHz, or bypass, which skips the upsampling altogether. By the by, there are two separate toroidal transformers, one for the digital and another for the analog sections of the DP200, in case you were wondering.

Despite its myriad of features and functions the DP200 was extremely easy to operate without even glancing at the manual, which is on the sparse side yet pretty helpful nonetheless. The digital volume control is said to use a single CS3310 control chip and ranges from zero to 60 in 0.5-step increments. All I can say is that it worked very intuitively and in sufficiently small steps that I was always able to find the exact volume level I wanted.

I only used the DAC and preamplifier functions of the DP200, so I did not evaluate the ADC, phono section, or headphone performance of the unit. But it was nice to know they were available if I needed or wanted them.

My only serious beef with the DP200 from a function/design standpoint is that there is no balance control, which may not be a problem for some, but for me it’s like getting a Swiss Army knife without the tweezers. Then again, since you get all this flexibility, build quality, and thoughtful execution for a very reasonable $1995 USD, I suppose we have to expect compromise somewhere. But why’d it have to be the tweezers? Why not the stinkin’ toothpick instead? Why, you may ask, am I making such a big deal about this? Because I have so little else to complain about here!

As a DAC

My first step in reviewing the DP200 was to decide which function to test first. I settled on the DAC section because it was marginally easier to integrate into my system, and because I hold my own Electronic Visionary Systems DAC in high esteem (if I don’t say so myself) I thought this would be the easiest thing to shoot down -- er, get a handle on fairly quickly.

Not so fast. As I sat there, pen poised waiting to start ripping things apart, I realized I didn’t have anything to write about. Out of the box the DP200 sounded right on par with my reference DAC. Yikes! The thing about reviewing high-quality stuff -- I mean really high-quality stuff (which in my book means equipment that sounds fundamentally neutral) -- is that it’s always tough to find things to write about. It’s the same as with the evening news -- always easier to report on the negative than the positive. The DP200 simply wasn’t giving me any dirt to report on.

Associated Equipment

Loudspeakers –  Soliloquy 6.2.

Amplifiers –  McCormack DNA 0.5 Rev. A.

Preamplifier – Marsh Sound Design MSD-P2000b.

Digital – Pioneer DV-C302D DVD player (used as transport), Electronic Visionary Systems Millennium DAC 1.

Interconnects – Acoustic Zen Matrix Reference II and Silver Reference II.

Speaker cables – Acoustic Zen Satori shotgun biwire.

Digital cable – Apogee Wyde Eye coaxial.

I initially kept the DP200 in bypass mode because I wanted to use my reference DAC as a basis for comparison and it is not an upsampling unit. When it comes to comparisons this fine I tend to pull out the reference material I know best so I can start to get some kind of a grip on what I'm hearing. So out came Keb’ Mo’s Slow Down [Okeh/550/Epic BK 69376] to help me uncover what was happening with the frequency extremes. The first thing that hit me was that on the title track the bass was noticeably tighter and quicker than I was used to. This had the effect of bringing the whole sonic performance into better balance, which immediately improved the effortless-enjoyment factor. The hi-hats at the beginning of this track are also very revealing of the quality of reproduction equipment, and the DP200 seemed to be doing an even better job at portraying both the clarity and tone of this notoriously difficult-to-get-right instrument.

The Keb’ Mo’ disc also served to show that the DAC section of the DP200 was certainly not lacking in dynamic prowess or presence. Individual instruments popped out of the mix and claimed their own space as much as I’ve ever heard, and everything from guitars to snare drums had the tonal depth I’ve come to expect from this disc. In short, I didn’t feel as if I were missing anything, and all the while there were no unnatural or manufactured sounds creeping in to take my attention away from the music. The words that kept coming to mind were "transparency," "detail," "refinement," and "transparency" again. What seemed to be obviously lacking was any kind of "smoothing," "homogenizing," "editorializing," or "augmenting" to achieve a certain sound or subjective sense of musicality.

Switching from bypass mode to 24/192 brought about a slightly more voluminous soundstage and slightly fatter images, but that’s about it. Moving on to 24/96 land had the effect of shrinking individual images and the whole soundstage slightly while adding a bit of edgier detail and transient snap to the mix -- kind of like when the eye doctor increases your prescription to improve clarity but shrink down everything you see. Going to 16/48 went a step further in that same direction and provided quite a contrast to the bypass and 24/192 modes. In comparison, 16/48 comes across like a pure sports car where you see, feel, and hear every little nuance of the driving experience, whereas 24/192 has a much more fluid and leisurely presentation with fuller, rounder tones and softer edges.

A couple of important things to note for perspective. Each individual mode was of extremely high quality such that nothing in any mode came across as sounding wrong. In fact, I felt that if the DAC got stuck in any one mode I could live very happily ever after. Each mode just seemed to have its own individual take on what was being fed to it and was portraying the music as best it could. From a listener’s standpoint, I felt like I had four legitimate ways to experience my music depending on what I thought sounded right to me. Though I tended to stay in bypass mode through most of the review, I could see myself eventually settling on different modes for different discs. Hey, it’s always nice to have options, especially if they come at very little or no cost in terms of quality or expense.

There was one other significant discovery I made while using the DP200 as a DAC. As I mentioned earlier, April Music highly recommends running in balanced mode whenever possible (as does Marsh Sound Design, the maker of my preamplifier), and from what I heard I’d heartily agree. As good as things were with single-ended connections, balanced connection upped the ante to another level. Most noticeable was the added sense of dimension to both the soundstage and individual instruments. The best way I can describe the effect is to picture a 3-D ball of sound that is produced by a performer, almost as though he's creating a sonic bubble, which is how I think sound actually projects during a live performance. What the balanced mode bought back was the rear section of the bubble such that in addition to hearing the forward-projected sound I also had a much better feel or sense for sound emanating rearward. Not only did this improve the perceived realism of individual performers, but it also helped me more effortlessly identify them in space without my brain having to fill in as many gaps. The effect was not unlike adding high-quality power conditioning to a system, and just as with good power conditioning, once you hear it you don’t want to listen without it.

It’s important to note here that it’s impossible to determine how much of the improvement was coming from the DAC and how much from my preamplifier running balanced, but it seems likely to me that each was at least partly responsible.

As a preamp

If I went into the DAC portion of this review with limited expectations, such was not the case with the DP200 as a preamplifier, given how high the former had set the performance bar. I was expecting to be let down here because, after all, with a top-level DAC already on board how good could the preamplifier possibly be for a total asking price under two grand? As it turns out there is more than a little family resemblance in the sonic characteristics between the preamplifier and DAC functions of the DP200.

One disc that is quickly becoming a staple in my diet is Sera Una Noche [M A Recordings M052A] because it combines excellent recorded sound with music that is endlessly enjoyable to listen to, at least for my tastes. It’s also a great reviewing tool because there is a crystal-clear and expansive soundstage incorporating lots of individual and diverse instruments and vocals nicely placed throughout the space. As with the DAC section, the preamplifier came across as supremely transparent, but not at any appreciable expense of tonality. On "Tanguito Del 2000," the bass clarinet (at least that’s what it sounds like) comes in rather strong just inside and behind the left speaker, and the DP200 conveys all the richness of the instrument without sounding the least bit hard or strained. And again, the ability of the DP200 to capture and communicate reverb trails all around the instrument helped to relay a good feel for the size of the recording venue, which in this case was a monastery in Argentina. At the beginning of "Quejas De Bandoneon," the recorder starts prominently in the middle of the stage, and what was notable was that the air being expelled from the instrument never sounded hissy or distorted. The clean portrayal of this facet of the performance yielded strong insight into various inflections and how the instrument was being played, yet detail in general was never overly obtrusive or spot-lit. The song really finishes up strong in the last minute, and the DP200 kept the pace moving along nicely. I found myself doing that involuntary-movement thing to the music.

One acid test I like to use, especially on lower-priced solid-state offerings, is Eva Cassidy's Live At Blues Alley [Blix Street Records G2-10046]. I find that less-refined pieces will frequently impart an unnatural electronic sheen that rides alongside Cassidy's vocals. The DP200 added no such accompaniment, and the DP200's unwavering transparency really performed to the point where I was left fruitlessly searching for something to complain about.

I popped Keb’ Mo’ back in for an encore to enact the same stress test I administered to the DP200's DAC section, and once again the preamplifier held its own by providing a balanced, tight, detailed, and unobscured view of this disc. Once more the highs and lows were exemplary, and the only thing that even evoked the slightest hint of question was the measure of dynamic power projected by individual instruments and vocals. I liken this to stepping up from a very high-end but lower-powered amplifier to a more powerful model that seems to be able to propel images into the room with just a tad more force. That I had to dig this deep before finally finding some nit to pick is testimony to the refinement and quality of the DP200 as a standalone preamplifier.

All together

Using the DP200 as both preamplifier and DAC proved interesting. Given the sonic similarities between the DAC and preamplifier sections, I was pretty sure of what I was going to hear with both working in concert. I got what I expected. Both the top and bottom ends of the spectrum maintained their relative strengths, and transparency reigned supreme, again with no apparent loss of tonal expressiveness. There continued to be a lesser sense of robustness and power as noted previously, but this was countered by improved dimension and space.

In short, it was nigh impossible for me to listen to the integrated DP200 and come up with serious criticism. One may ask for or prefer some different character or additives to enhance the listening experience or make up for other system shortcomings, but I can’t commit to identifying anything straying from neutral when listening to the DP200.

But this brings about my biggest nit to pick with regard to the DP200, which is also one of its virtues: its two separate functions (phono and ADC options excluded) are combined under one roof. The good news is that along with saving space and money you don’t have to mess with an extra set of interconnects, but the bad news is that you don’t get to experiment with different interconnects to customize the sound to your liking within the context of your system. Of course you can always play with different interconnects between the DP200 and the amplifier, but you do give up one element of control that true separates provide.

Comparisons

I used my in-house reference Electronic Visionary Systems Millennium DAC 1 ($750) and Marsh MSD-P2000b ($1495) for comparison purposes as together they cost about the same as the DP200. In an apples-to-apples comparison (i.e., keeping interconnects constant) the DP200 sounded more controlled, incisive, and clearer overall, while my units sounded more robust, powerful and tonally full -- but not necessarily richer. With respect to the DAC function, I thought the DP200 projected a better sense of dimension than the EVS DAC 1 so that objects were more clearly placed within a three-dimensional plane, although the DAC1 may have had a slight edge in presenting a larger-scale performance.

What all of the units share is a clean delivery of detail, which they all portray with a distinct lack of grain, glare, hardness, or other nasties that can often creep into the nature of a solid-state beast. Interestingly, by switching interconnects around I was able to get my reference units to sound very close to the DP200 and vice-versa, but that doesn’t change the inherent character differences as stated above.

Conclusion

Used separately as a DAC or stereo preamplifier the DP200 comes as close to beyond reproach as any component I’ve had in my system. It represents the first time I’ve had a preamplifier operating in class A in my system, and I don’t know what, if anything, such a design adds (or maybe more accurately doesn’t add) to the ultra-refined and transparent sound, but I can say for sure that it certainly didn’t hurt. And the fact that running the DP200 in balanced mode seems to bring its performance to an even higher level has me seriously thinking about moving that way.

But for those who seek Swiss Army knife -- um, Leatherman -- utility and versatility in conjunction with no-apologies-needed performance, I can't recommend the DP200 more highly. That you get all the DP200's flexibility, build quality and astounding performance for less than two large borders on the absurd.

...Tim Shea
tims@soundstage.com

Stello DP200 Digital-to-Analog Converter/Preamp
Price:
$1995 USD.
Warranty: Two years parts and labor.

April Music, Inc.
Seorae Bldg., 773-1 Bangbae-Dong
Seocho-Gu, Seoul 137-829
South Korea
Phone: 82 2 3446 5561
Fax: 82 2 3446 5564

E-mail: info@aprilmusic.com
Website: www.aprilmusic.com

US distributor:
Bertrand Audio Imports
49 Fairview Avenue
Nashua, NH 03060
Phone: (603) 883 1982
Fax: (603) 880 4533

E-mail: bertrandaudio@comcast.net

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