April Music Stello DP200 DAC/Preamplifier

Equipment report
Solid-state preamplifiers
April Music Stello DP200
April Music Stello DP200 DAC/Preamplifier

Only a couple of years ago I was convinced that a new generation of high-resolution digital formats, SACD and DVD-Audio, was poised to grab the baton from flagging Red Book CD and run with it. At that time I probably wouldn’t have considered reviewing an upsampling DAC/preamplifier like the April Music Stello DP200—so passé, so PC…M. Of course, I never would have guessed that both of the high-res formats would do a swan dive into an empty pool, either. Today, even with high-resolution multichannel audio waiting in the wings as part of the new high-definition DVD standard, a product like the Stello DP200 becomes a lot more appealing. Like they say—the only constant in life is change.

April Music of South Korea produces a full line of mid- and high-level electronics, the Stello and the Eximus respectively. 1 April describes the solid-state Stello DP200 as an “all-in-one Audio Center for Digital and Analog Convergence.” Equipped with multiple digital inputs (and a pair of analog inputs), it accepts the PCM signal of up to four components—from a CD or DVD transport to a television set-top box. Its upsampling digital-to-analog converters offer selectable sampling rates of 48kHz, 96kHz, and 24-bit/192kHz, available on the fly. Included is a pair of bypass inputs, whereby a controller can take command of the stereo left/right speakers in a multichannel setup. Stello also addresses the archiving market with a brace of modular options. There’s the P1 phono module that is adjustable for moving-magnet or moving-coil cartridges with six gain and six impedance settings via internal DIPswitches. Add to that the ADC-1 analogto- digital converter with its 24- bit/96kHz capability, and you can record treasured LPs, radio broadcasts, or tapes for digital safekeeping. Stello is rightfully proud of its first-rate headphone section, which taps into the Stello’s analog amplifier circuitry, avoiding sounddegrading op-amps. It’s preternaturally quiet and has a pleasantly warm sound, and though the Stello can’t match the velvety resolution and transparency of, say, an EAR headphone amp, my AKG K501 phones have rarely sounded better. The Stello look is aerospace smooth—the one-piece aluminum top panel wrapping neatly beneath the unit. Seven pushbuttons handle the most significant front-panel functions, which include a 120-step digital volume control divided into 0.5dB steps. A brightly- lit sixteen-character display makes listening- chair adjustments a breeze. Fortunately, the Stello memorizes the last volume setting used for each input; otherwise, the lack of a traditional volume control knob would be especially discouraging. April Music completes thepackage with a metal-alloy remote control that’s heavy enough to exercise with, but unremarkable for its ergonomics.

In terms of sonic performance, sometimes it’s what you don’t hear that makes the strongest impression. The DP200 was without doubt one of the quietest preamps I’ve encountered in some time. Music emerged from the soundspace with astonishing purity and detail, and no vestigial comet-trails of noise. Initially its sonic character seemed sterile, but these assessments were made with a cold unit straight from the box. Within a few short hours the Stello’s performance warmed considerably. Through the analog or digital inputs the midrange had an almost cushiony smoothness—a relaxed warmth that set images back from the listener a row or so. Female and male voices were reproduced with equal excellence. Bass was deep and boasted pitch definition that might not rattle the likes of a Krell but should shake up some of the competition in the under-$2k market. Acoustic bass, notoriously difficult to get right, sometimes got a bit wooly and ill-defined, but this was by no means the case in every instance. For example when Holly Cole sings Tom Waits’ “Looking for the Heart of Saturday Night” [Temptation, Alert], the ripe acoustic bass sounded a little over-stuffed and underdamped, yet on Mary Stallings Live at the Village Vanguard [MaxxJazz] the bass had a muchimproved balance of pitch and extension.

Although the treble range continued to skew to the cooler, more clinical side of the spectrum, even after break-in, it was never less than highly listenable and non-fatiguing. Occasionally on piano transients there was a trace of smearing, and the thinnest glaze seemed to overlay high-speed upper-octave glissandos [One On One, Clark Terry, Chesky]. The sibilance range of vocalists was neutral and immediate, with the requisite transient speed and no grating edginess. Macrodynamics were vivid, but micro-dynamic contrasts were more reserved—the energy level less lively during a recording’s quieter moments. Thus resolution of the most delicate inner voices was a little less than transcendent. Even so, transparency was very good at most levels, even revealing the occasional recording gaffe that astute listeners often encounter (e.g., the studio door being shut, or rather “slammed,” at the fourand- a-half minute mark of Kissin’s lovely piano rendition of Glinka’s The Lark—it’s a surprisingly audible slam, too, even though it’s way, way upstage). Switching between upsampling rates reinforced the truism that resolution cannot be added but only subtly enhanced. Generally I preferred the increased openness of 96kHz or 192kHz upsampling, but results for all sampling rates were variable at best (sometimes indeterminable) and contingent on the quality of the recording itself. The harmonic density of classical music tended to favor the higher sampling rates. At 192kHz, Evgeny Kissin’s piano during Pictures at An Exhibition [RCA] had a reduced sense of constriction and a greater feeling of bloom. Similarly there was an openness, an expressiveness, that filled Fiona Apple’s vocal on the title track to Extraordinary Machine [Epic]. At lower sampling rates her voice sounded as if some of the texture and air had been tamped down.

The Stello DP200 is mildly subtractive in the areas of soundstaging and imaging. It doesn’t fully conjure up a thickly populated soundstage of musicians. Malcolm Arnold’s brassy Sussex Overture [Reference Recordings] was vividly rendered but lacked the depth of a real stage—appreciably wide but not especially dimensional. There was a trace of image smearing, a depletion of the air and distance among players. I noted a similar effect during mezzosoprano Audra MacDonald’s version of “Lay Down Your Head” [How Glory Goes, Nonesuch]. She begins the song singing gently a cappella and is later joined by harp, cello, violin, and winds. Virtually every sonic element falls smoothly into place with the exception of a general flattening of soundspace that subtracts some of the luster and liveliness of the performance. I’m not entirely certain what is going on here, but experience suggests that when the finer gradations of dynamics are constrained, the perception of soundspace and dimensionality is diminished.

Word to the wise: If you’re considering running a set-top box through one of the digital inputs be careful you don’t inadvertently tune to a Dolby Digital broadcast. The DP200 is not a surroundsound decoder, and multichannel Dolby Digital will send a cascade of digital detritus chirping through the speakers.