Digital Processors
Editor's Note: The sound of any particular CD transport/digital processor combination will be dependent on the datalink used-see "Bits is Bits?" by Christopher Dunn and Malcolm Omar Hawksford, Stereophile, March 1996, Vol. 19 No.3 (WWW). Unless mentioned, processors are limited to 32/44.1/48kHz sample rates. To be included in Class A+, a digital processor must be capable of handling DSD or 24/96 LPCM data.
We strongly recommend those interested in using a computer as a true high-end digital audio source visit our sister website www.AudioStream.com, which is edited by Michael Lavorgna.
A+
Antelope Audio Zodiac Platinum Bundle: $5295 (with Voltikus power supply)
From the makers of the Class A–rated Zodiac Gold comes the Zodiac Platinum, which bundles a D/A processor, headphone amp, and preamp into a small but chunky (6.5" W by 4.4" H by 7.6" D) enclosure. (The similarly chunky Voltikus power supply is slightly less wide.) Like the Gold, the Zodiac Platinum offers PCM performance through 384kHz, but adds DSD64 and 128 via USB (DoP), which it upsamples to DSD256, Antelope Audio claiming direct DSD-to-analog conversion. Technical highlights include FPGA processing for some functions and "Oven-Controlled Clocking," in which jitter is kept low through thermal stabilization of the word clock's crystal oscillator. User controls appear on both the front panel and the remote handset, the former distinguished by a hefty, nice-feeling volume knob—although JI noted that it "produced a bit of a raggedy zipper sound" through his system when he adjusted the volume. With some musical selections JI noted the Platinum's "slightly thicker bottom end" compared with another premium processor, and with other tracks a thicker sound overall, adding that "both [processors] excelled at creating a transparent path to my power amps." As for the Zodiac's headphone amp, "I'd never heard better sound from my Grado HP1s," JI declared. JA wrapped up: "Overall, the very good measurements of Antelope Audio's Zodiac Platinum indicate excellent digital and analog engineering." (Vol.37 Nos.9 & 10 WWW)
Auralic Vega: $3499
The elegant-looking Vega D/A processor is housed in a slim, brushed-aluminum enclosure and has a front panel dominated by a wide, rectangular, yellow-on-black OLED display. The rear panel offers single-ended and balanced outputs, and five digital inputs: transformer-coupled AES/EBU on an XLR, two transformer-coupled coaxial S/PDIFs on RCAs, one optical S/PDIF on TosLink, and a high-speed USB2.0 port. The AES/EBU and S/PDIF inputs handle 16- and 24-bit data with sample rates up to 192kHz; the USB port also operates with sample rates of 352.8 and 384kHz, and will accept DSD64 and DSD128 data. A Sanctuary audio processor upsamples PCM input data to approximately 1.5MHz and 32-bit depth, and implements four reconstruction filters for PCM data and two choices of low-pass filter for DSD data. Though it required several hours from cold before sounding its best, the Vega combined outstanding low-end weight and high-frequency extension with an exceptional sense of space, said JA, who also noted measured performance that was beyond reproach. "It's DSD and digital done right!" he exclaimed. (Vol.37 No.2, Vol.38 No.11 WWW) Ayre Acoustics QA-9: $4750 ★
Housed in the same compact chassis as Ayre's QB-9 USB DAC, the QA-9 is a solid-state A/D converter intended to allow audiophiles to make high-quality rips of their LPs. It uses an Arda Laboratories AT1201 two-channel A/D converter chip and operates at sample rates up to 192kHz, outputting 24-bit data via either a USB 2.0 or AES/EBU connection. Setup was simple and, aside from the tedious task of eliminating LP surface noise, use was straightforward. The Ayre offered smooth highs, a clean midrange, and an excellent sense of space. JA summed up: "When recordings you love have never been issued on a good-sounding CD, it makes sense to rip them with Ayre's QA-9—it's the closest thing to a truly transparent audio component I have encountered." He bought the review sample. Now includes DSD and Word Clock outputs on transformer-coupled BNC jacks and outputs DSD via USB. (Vol.35 No.11, Vol.36 No.4 WWW) Ayre Acoustics QB-9 DSD: $3450 ★
The QB-9 is an asynchronous transfer mode, USB-input DAC with Ayre's minimum-phase digital reconstruction filter implemented in Field-Programmable Gate Array. It uses a Texas Instruments TAS1020B chip, supporting sample rates up to 96kHz and word lengths up to 24 bits. High-resolution digital files "popped with life" and were marked by a natural flow and physical impact that allowed WP to form a deeper emotional connection with the music. JA: "Ayre's QB-9 is well engineered, offering excellent performance in both the analog and digital domains, and is not compromised by its having just a USB data input." JI felt the QB-9 exceeded the YBA WD202 and Benchmark DAC1 USB in terms of spatial detail, depth, and width, while adding a touch of seductive clarity. "Wow!" The latest version of the QB-9 uses an XMOS XS-1 microprocessor chip and supports sampling rates via USB2.0 up to 192kHz. Earlier QB-9s can be upgraded for $250. Compared with the Resolution Audio Cantata, the Ayre tended to exaggerate sibilants on some recordings but provided a warmer, fleshier midrange, felt JI. Compared to the NAD M51, the Ayre had slightly greater punch and better dynamic edges. Compared to the much more expensive MSB Diamond DAC IV, the QB-9 had a very slightly more aggressive midrange, but otherwise held its own, said JI. Current production as of mid-2013, auditioned by AD in connection with his AX-5 review in Vol.36 No.7, uses an ESS Sabre DAC chip, offers improvements to the USB chip power supply, and will decode DSD data. Stereophile's "Joint Digital Source" and "Overall Component" of 2009. (Vol.32 No.10, Vol.33 No.6, Vol.34 Nos.7 & 11, Vol.35 Nos.7 & 10, Vol.38 No.11 WWW)
Benchmark Media Systems DAC2 HGC: $1995 $$$
Although similar in appearance to previous Benchmark models, with a front-panel volume control and two 1/4" headphone jacks, the new DAC2 HGC uses four 32-bit ESS Sabre DACs, run in balanced configuration, for a significantly lower noise floor; has a new Hybrid Gain Control (HGC) for volume attenuation, which combines active analog gain control and passive low-impedance attenuators in the analog realm with a 32-bit digital DSP gain control for digital signals; and provides front-panel displays for both sample rate and word length. Though it lacks a balanced AES/EBU input, the DAC2 HGC offers two analog inputs and five digital inputs: two optical, two RCA coaxial, and one asynchronous USB that handles resolutions up to 192kHz as well as DSD64. It had a pleasantly forward sound, with smooth highs, a solid bottom end, and excellent image separation, said EL. Compared to the Auralic Vega, the Benchmark had a similarly smooth top end, but lacked the Vega's sweet midrange and outstanding portrayal of space, said JA. JI noted the DAC2's good scale and sense of ambient space, but found it lacked focus compared to the considerably more expensive MSB Analog DAC. (Vol.37 No.2, Vol.38 No.11, Vol.39 No.10 WWW) Bricasti Design M1 DAC: $8995 ★
With first-class fit'n'finish and uncluttered exterior design, the dual-mono M1 DAC measures a rack-friendly 17" W by 2" H by 12" D and weighs 12 lbs. It offers four digital inputs (S/PDIF, AES/EBU, BNC, optical), accepts sampling rates up to 192kHz, and, as of 2013, adds a USB input, volume control, remote control, and DSD decoding. The Bricasti's fast, detailed, powerful sound made the much less expensive Musical Fidelity M1DAC seem veiled, muffled, and slow, said JM. "The best digital playback I have heard," he concluded. Compared with the Weiss DAC202, the Bricasti was less forgiving of poorly recorded material, but had bigger, deeper, better-defined low frequencies; compared with the dCS Debussy, the Bricasti sounded very slightly warmer and was very slightly more transparent, said JA, who also praised the M1's state-of-the-art measured behavior. A firmware update (free to registered owners) adds minimum-phase digital filter options, digital phase inversion, and a digital volume control. Compared to its previous filter set, the Bricasti's minimum-phase sound was much richer, with more body, more coherence, and less grain, said JM. Used as a line source in place of Parasound's Halo JC 2 preamp, the Bricasti produced a more coherent sound, with deeper, tighter, more powerful bass. "My personal best just got better," JM concluded. Now ships with asynchronous USB input (not yet auditioned), and will decode DSD data. Production in 2013 replaces the switch-mode power supply of the M1's digital-routing section with a linear supply based on a custom-wound transformer. With the new power supply in place, JM heard improved bass extension and greater overall clarity. Owners of original M1s (made prior to March 2013) can have their units updated for $200. In 2014, Bricasti offered to M1 owners even more additional refinements: a remote-control kit, involving a separate infrared receiver that plugs into the rear panel ($500 for M1s presently in service; included in the price of new units); a changeover, performed at the factory, from multiple glass-and-wire fuses to a master circuit breaker ($150); and an upgrade, also done at the factory, to DXD and DSD64/DSD128 capabilities ($400). As impressed as he was by the last, JM remained philosophical: "the fact that Bricasti's M1 can now play DSD and DXD files is less important than the fact that its playback of plain old 'Red Book' 16-bit/44.1kHz audio is so compelling that I, for one, don't feel shortchanged when a good recording is not 'high-resolution.'" He observed that, yet again, his personal best in digital playback just got better. (Vol.34 No.8; Vol.35 Nos. 2, 3 & 9; Vol.36 No.7; Vol.37 No.12 WWW) exaSound e28 Mk.2 multichannel DAC: $3299
See "Music Surround-Sound Components" (Vol.36 No.11 WWW) Grace m905: $3495
From the pro-audio world comes the Grace Designs m905 Monitor Controller: a combination line stage, D/A converter, and headphone amplifier designed as a control center for music playback in a recording studio. As befits its provenance, the m905 is rack-mountable, with most of its controls built into an umbilical-connected, iPad Mini–sized remote that, according to JM, exuded an "Authentic German Engineering" level of quality, even though Grace Designs is based in Colorado. The m905 is built around the Burr-Brown PCM1798 DAC chip, plus an XMOS USB receiver, and it offers, via the DoP standard, DSD streaming: the first product from Grace Designs to do so. Already a fan of the "ever-so-slightly euphonic" Grace m903—which was Stereophile's Headphone Product of the Year for 2012—JM was "taken aback at how much better the m905 sounded," and quantified the depth of his delight at the new model's DSD capabilities with two words: "Woober Joobers!" He said that, all in all, the m905 is "among the most impressive pieces of audio gear" he has ever evaluated. (Vol.37 No.4 WWW)
Luxman DA-06: $4990
Among the earliest and most notable products to emerge from the burgeoning world of DSD streaming, the Luxman DA-06 is a full-size D/A processor built around a Burr-Brown PCM 1792A 32-bit converter chip. The DA-06 supports 2.8224 and 5.6448MHz DSD files and, via its USB input, PCM files up to 32-bit/384kHz. Front-panel controls include the ability to select among three different PCM filters and between two sets of DSD rolloff characteristics, as well as to invert absolute signal polarity on the fly. AD, who acknowledges "DSD's prowess at communicating the subtleties of musical flow," observed that the Luxman sounded "generously explicit, [with] musical and sonic details in abundance and . . . a soundfield notable for its openness and general lack of murk. Still, the DA-06 had good substance, with a tonal character that was slightly—almost imperceptibly—warm and round." In his measurements, JA noted that the Luxman's low levels of harmonic and intermodulation distortion are offset somewhat by marginally poorer-than-expected jitter and noise-floor numbers—yet he declared that, overall, "the DA-06's measured performance is simply superb." AD's conclusion: "a damn fine-sounding D/A converter with virtually all music." (Vol.37 No.7, Vol.38 No.11 WWW) Moon by Simaudio Evolution 780D: $15,000
Compared with Simaudio's Moon Evolution 650D and 750D transport-converters, the new Evolution 780D does away with physical media altogether, forcing those who desire real-time CD playback to use an external transport or a CD player with digital outputs. That said, also in comparison with the company's previous processors, the 780D adds both processing power—it can handle PCM files up to 384kHz and DSD up to 11.2896MHz, and its femtosecond clock is claimed to produce lower jitter—and power power: the 780D features the company's Moon Hybrid Power (MHP) power supply, with conductive polymer capacitors and other refinements. The 780D also includes Simaudio's Moon intelligent Network Device (MiND), a music-streaming application accessible via Ethernet or built-in WiFi. MF described the new Moon's improvements over the 650D as sounding "evolutionary rather than revolutionary"; however, when used with the best recordings at hand, "the 780D's transparency and graceful yet superbly detailed transient performance combined with an absence of . . . digital artifacts to produce what was among the most transparent, if not the most transparent digital sound I've heard." MF also observed that the 780D's manual is insufficiently helpful, especially regarding the MiND application, and that the product lacks, at least for now, support for Roon or MQA. JA uncovered nothing but "superb measured performance." (Vol.39 No.8 WWW) MSB Analog DAC: $6995
The MSB Analog DAC combines a high-tech chassis machined from a solid billet of aluminum—it stands less than 1" tall yet weighs nearly 30 lbs!—with a circuit architecture that allows the buyer to select among five digital-input options, two power supply options, a WiFi option, and more—combinations of which can bring the price to just under $12,000. (For $6995, you get one digital input and the stock power supply.) The Analog DAC supports PCM and DSD up to 384kHz, employs a custom-designed, linear-phase apodizing digital filter, and offers single-ended and balanced analog outputs. JI was impressed with the MSB's "thereness," observing that, "With a DAC like the MSB, you get a sense of someone hitting Play on a big reel of wide-track analog tape, after being fed by live mikes in a room." Notwithstanding a couple of performance glitches, both solved by in-the-field firmware updates, JI found it difficult to part with his review sample: "It notched my system up to a place where almost all digital sources had an organic, natural presence without sacrificing the accuracy and detail present in the best recordings." JA noted that high-level signals produced some low-level distortion products, but otherwise found the MSB rare in being "so well thought out and so well engineered." Optional Volume Control: $995. Optional Analog Power Base: $2995. UMT Plus: $5995. Optional Dual Signature Power Base: $4995. (Vol.37 No.4 WWW)
NAD M51 Direct Digital: $1999 $$$ ★
The M51 is an attractive, full-width D/A converter with a digital volume control and useful front-panel vacuum-fluorescent display that indicates input, volume status, and sampling rate. It offers AES/EBU, coaxial, optical, USB, and two HDMI inputs, as well as analog (one pair each single-ended and balanced) and digital (HDMI) outputs. While all of the NAD's inputs can handle PCM audio data of resolutions up to 24-bit/192kHz, the M51 converts everything it receives to a pulse-width-modulation (PWM) signal at a sampling rate of 844kHz, controlled by a clock running at 108MHz. The NAD had a "wonderfully detailed and revealing sound," said JI. JA noted measured performance that was "almost beyond reproach." Compared to the Auralic Vega, the NAD produced a cleaner, leaner, airier, less forgiving sound, said JA, though he still highly recommends the M51 as a great value for the price. Readers have reported—and JA has now confirmed—that the M51's earlier v.1.39 firmware offers a better, "fatter" sound than the later v.1.41, probably due to a 1dB higher output; later versions of the M51 can be easily "rolled back." to v.1.39. (Vol.35 No.7; Vol.37 Nos.2 & 5 WWW) PS Audio PerfectWave DirectStream: $5999
Instead of an off-the-shelf chipset, PS Audio's first DSD processor uses original code written by hand into a field-programmable gate array (FPGA)—the result being a system that converts all incoming data to double-rate DSD. In addition to asynchronous USB, digital inputs include RCA, TosLink, and HDMI, and both single-ended and true balanced analog outputs are provided. The DirectStream is built on a cast-alloy chassis with a glossy MDF top—and a touchscreen from which all user controls can be worked. (A remote handset is included.) Firmware is user-updatable, as AD discovered while reviewing the DirectStream—during which time he noted its "excellent pacing, flow, correctness of pitch relationships, and the like, as well as a consistently smooth and slightly laid-back sound." With some files, AD found the DirectStream just a little too laid-back—a condition mitigated in part by that firmware update—but found its musicality beyond reproach. JA observed that the DirectStream "measures superbly well" in many ways, but was troubled by its poor linearity at low frequencies and its "ultimate lack of resolution" with hi-rez files. But he admits that its sound quality is still very satisfying. In his Follow-Up, RD—whose listening is centered more around discs than downloads—tried the DirectStream DAC with PS Audio's PerfectWave Memory Player transport ($3995), and observed, "listening to familiar recordings . . . I heard more musical detail from them than I previously had. This detail was not a matter of exaggerated treble, which can give an impression of increased detail, but was genuinely higher resolution manifested by greater differentiation among the sounds of instruments and rhythmic patterns." Subsequent to that audition, RD received and installed in the DirectStream DAC a new firmware upgrade that brought his unit to v.1.2.1. His verdict: "The latest firmware represented a major improvement over the one that I and Art Dudley and Michael Lavorgna had. Soundstages were now deeper and wider, and well outside the speakers' positions with some recordings; and images on those stages were now more 'rounded,' more three-dimensional. The bass was cleaner, with better-defined transients." Following the firmware update to v.1.2.1, JA retested the DirectStream DAC and found a lower noise floor, increased low-level linearity, and a dramatic reduction in low-frequency distortion. Said JA: "Kudos to PS Audio for designing a product so that its performance can so easily be upgraded by its customers." Four months after the upgrade to v.1.2.1, PS Audio updated the DirectStream DAC's operating system to a version referred to as Pike's Peak—which, in RD's estimation, "seemed to transform the . . . sound: more dynamic, better bass, more extended treble, even better soundstaging." Writing in a subsequent Follow-Up, RD reported on PS Audio's more recent Yale software upgrade, said to include more accurate filters and to represent a different approach to jitter reduction. He said that, in comparison with Pike's Peak, Yale offered slightly softer trebles and was "more subtly detailed"; he concluded that Yale is the superior operating system. (Vol.37 No.9, Vol.38 Nos. 2, 3, 5, 11 WWW) T+A DAC8 DSD: $3995
See JI's review in this issue. TotalDAC d1-tube-mk2: 9100
In a design field where cats are skinned in any number of ways, Vincent Brient of the French company TotalDAC takes a distinctive approach: for his D/A converters, he uses a discrete R2R ladder comprising some 200 hand-selected, very-high-quality discrete resistors per channel. The nonoversampling d1-tube-mk2 supplements this circuitry with an FPGA for various digital chores, an XMOS USB receiver (S/PDIF, TosLink, and AES/EBU digital inputs are also provided), and a tubed output stage. DSD (DoP) compatibility is a 320 option. All inputs support 24-bit/192kHz resolution except TosLink, which maxes out at 24/96. In the experience of ML, to whom digital recorded sound manifests itself as a sheet of glass between himself and the performers, "listening to music through the TotalDAC d1-tube-mk2, there was no glass; I could listen to my music as deeply as I wanted to go." Which pretty much says it all. (Vol.39 No.1 WWW)
A
Audio Note DAC 2.1x Signature: $5500
In common with other Audio Note D/A converters and CD players, the DAC 2.1x Signature is built around a rather old-school 18-bit Analog Devices 1865 chip, said to be hand selected. Neither oversampling nor digital filtering is used, nor does the DAC 2.1x Signature contain an analog filter; according to Audio Note, the converter's use of a transformer as an I/V stage confers on the output signal sufficient treble rolloff. The tubed output stage is built with Audio Note's own copper-foil-in-oil signal capacitors, and signal output is handled by Audio Note Silver interconnect cable. Digital inputs are limited to S/PDIF (RCA) and AES/EBU (XLR); a USB input is not offered. After using it with Audio Note's own CDT One/II disc transport, AD praised the DAC 2.1x Signature for its sonic heft and substance, its analog-like momentum and flow, and, overall, a knack for "bringing out the goodness of good recordings, [although it] also had a knack for accentuating the badness of certain types of bad recordings." While testing the DAC 2.1x Signature, JA discovered distortion products, noise, jitter, and data truncation (24 to 18 bits), leading him to describe the Audio Note as "broken." (Vol.39 No.1 WWW) Benchmark Media Systems ADC1 USB: $1795 $$$
Housed in the same small case as Benchmark's DACs, the ADC1 is a 24-bit USB A/D converter with a Texas Instruments TAS1020B USB chip and a 128x-oversampling, delta-sigma AKM 5394 A/D converter chip. It offers a pair of balanced analog inputs on XLRs, two unbalanced AES/EBU Aux outputs on BNC jacks, a USB Type-B port, a Main TosLink output working in either S/PDIF or ADAT format, a Main balanced AES/EBU output on an XLR, and word-clock input and output on BNCs for use in multichannel systems, slaved to other converters. Though it lacked the Ayre Acoustics QA-9's delicately drawn soundstage, the Benchmark produced a natural, coherent overall sound, with clean high frequencies and weighty, extended lows, said JA, who also noted superb measured performance. (Vol.37 No.2 WWW) Cambridge Audio Azur 851D: $1649 $$$
Designed in the UK and manufactured in China, the Cambridge Azur 851D DAC-preamplifier is well-finished and somewhat surprisingly solid for its price range. It upsamples everything to 24-bit/384kHz, and most of its inputs can handle 24/192 datastreams. The Azur 851D also has a headphone jack, three switchable filter settings, a choice of balanced and single-ended outputs—and, for the fun of it, Bluetooth wireless connectivity. It also has a sophisticated user interface, addressable by both its menu-driven front-panel controls and its comprehensive remote handset. In JI's words, "the Cambridge Audio Azur 851D has bang for the buck all over the place. It approached the sound of DACs costing four times as much—closely enough, I feel, to satisfy most audiophiles on a budget." After the 851D left his test bench, JA observed, "The Cambridge Audio Azur 851D's measured performance is never short of superb. The fact that it can offer this level of performance for $1500 puts many more-expensive processors to shame." In his Follow-Up, AD was put off by the Azur's "needlessly complex" control panel, but impressed all to hell and back by its musicality: "The Cambridge 851D is, indeed, a killer of giants. It is a D/A converter that uses its high resolution not to add amusical filigree or spatial puffery, but to enhance musical flow and drama. It really is that good. (Vol.37 No.12, Vol.38 No.2 WWW)
Chord Hugo TT: $4795
Chord's Hugo TT (for Table Top) combines a DSD-friendly USB DAC, headphone amplifier, and Bluetooth receiver in one distinctly styled and unambiguously chunky aluminum case. The user interface is distinguished by a volume control that uses not a knob or a pair of buttons but rather a captured glass marble that changes color as the loudness level changes, and a top-panel lens that gives the user a clear view of the color-coded sample-rate indicators inside. Key to the Hugo's performance are an internal chargeable battery—for power-supply isolation, not portability—and a field-programmable gate array (FPGA) running Chord's proprietary filter algorithms. Both on its own and in comparison with other DACs of his acquaintance, JI identified the Hugo's strengths as "detail, definition, and depth, with no distracting artifacts." He also declared: "The Chord Hugo TT sounded wonderful with headphones." In a dispatch from his test bench, JA said the Hugo "performed superbly well" on his jitter tests and was, all around, "an extraordinarily well-engineered component." (Vol.38 No.11 WWW) Lector Strumenti Digitube S-192: $3195
The full-width (16.9") Lector Strumenti Digitube S-192, which AD described as well built and well styled "without silly excess," is a D/A converter whose only user control, apart from its power switch, is a pushbutton that selects among its five digital inputs: RCA, BNC, TosLink, XLR (for AES/EBU), and USB. Its Japanese AK4397 DAC chip provides 32-bit performance at up to 192kHz, and it has an analog (non-switching) power supply and, in its analog output section, a pair of ECC81 dual-triode tubes. Using the Digitube primarily as a USD processor with his iMac and his decidedly tube-friendly music system, AD found that it offered "a near-analog portrayal of . . . colors and textures" and excellent impact and detail resolution, although its sense of scale was bested by the far less expensive Halide DAC HD. Yet in measuring the Digitube, JA noted "truly dreadful measured performance in the digital domain, along with [a] disappointing showing in the analog domain"—in light of which, greater-than-usual buyer circumspection seems appropriate. "Class A, for special tastes only," sums up AD. (Vol.37 No.6 WWW) M2Tech Young DSD: $1399 ★
Elegant and modern in appearance, the M2Tech Young is a DC-powered D/A processor with a simple aluminum case, a recessed front panel, and a large alphanumeric display. It uses a Burr-Brown PCM1795 DAC chip with a custom oversampling minimum-phase filter. It handles resolutions up to 32 bits via USB (24 bits via S/PDIF or AES/EBU), and sample rates up to 384kHz via USB (192kHz via S/PDIF or AES/EBU). While the Young lacked some accuracy and precision, it nevertheless managed an excellent balance of detail and warmth, said JI. Review was with the Palmer Power Station battery power supply, now replaced by the Van der Graaf low-noise power supply ($1199). Adding the Palmer resulted in significantly more focus and clarity. "The M2Tech combo seduced me," JI concluded. Current version will decode DSD128. (Vol.36 No.5 WWW)
Musical Fidelity V90-DAC: $299 $$$
Intended as a replacement for their V-DACII—itself one of ST's longtime reference components—Musical Fidelity's V90-DAC is housed in the same 6.6" by 4" by 1.8" brushed-aluminum case that characterizes the rest of the V90 line. This 24-bit converter, which uses a 32-bit Burr-Brown PCM1795 DAC chip, delivers up to 192kHz performance through its single coaxial (RCA) input and up to 96kHz through its USB and two optical TosLink inputs. According to ST, compared with its predecessor, "the V90-DAC offers still greater low-level resolution, superior dynamics, and fatigue-free listening." JA took the V90-DAC for a spin, going so far as comparing it with his current reference, the Auralic Vega. He noted the MF's combination of smoothness, naturalness, and detail, combined with good spatial properties—but he felt the V90-DAC was lacking, by comparison, in momentum and bass power. JA's measurements uncovered "a strange rise in the noise floor around the 19 and 20kHz tones, in only the right channel"; otherwise, the V90-DAC "definitely punched above its weight on the test bench." (Vol.37 Nos. 4 & 8 WWW) B CEntrance DACport: $199 ★
USB bus-powered D/A processor with volume control. See "Headphones & Headphone Accessories," where it is rated Class B. Used as a single-input preamp between a laptop source and a pair of Rogue M180 monoblocks in EL's main system, the DACport produced a large soundstage, a slightly rolled-off but grain-free treble, and a tube-like midrange. Compared to the Benchmark DAC1 HDR, the DACport lacked resolution and bass weight, but always sounded musical and tonally balanced. LX version sounds clearer, more transparent, and is rated Class B as a D/A processor. (Vol.33 Nos.6 & 10 WWW) Channel Islands Audio Transient Mk.II: $699
Housed in a small (4.45" W by 2.9" H by 5.25" D), nicely finished aluminum case, the Transient Mk.II is an asynchronous USB DAC with a 24-bit volume control and three digital outputs: S/PDIF via 75-ohm BNC, I2S via mini-DIN, and differential I2S via an HDMI jack. Six front-panel LEDs indicate the incoming signal's sampling rate: 44.1, 48, 88.2, 96, 176.4, or 192kHz. In a case identical to the Transient's, the optional VDC5 Mk.II high-current power supply ($329) feeds the Transient a linear 5V DC at 2.5A for reduced noise and ripple. Though it lacked some high-frequency focus and ease, the Transient Mk.II produced a well-balanced overall sound, with good soundstage size, respectable bottom-end heft, and a clean midrange, said JI. Measured performance was somewhat disappointing, however; JA found that, even with 24-bit data, the Transient offered resolution of just over 17 bits. (Vol.37 No.3 WWW)
iFi Audio iDAC: $299 ★
iFi Audio is a subsidiary of Abbingdon Music Research. The iDAC, iFi's first product, is a sleek, single-box D/A converter built into a 6"-long aluminum extrusion with an attractive textured finish. It uses an ESS Sabre DAC chip capable of handling resolutions up to 24-bit/192kHz, and has a single USB-B input, a pair of RCA jacks for line output, and a 3.5mm headphone jack with volume control. It can be powered by the user's computer or by iFi's iUSBPower 5V power supply ($199). Compared with the AudioQuest DragonFly, the stock iDAC had a better overall sense of touch on strings and percussion, and revealed greater richness and complexity in hi-rez music files, said AD. With the iUSBPower powering the iDAC, Art noted a subtly clearer sense of force in note attacks and better spatial presence around voices. "Highly recommended," he concluded. (Vol.36 No.5 WWW) PS Audio NuWave DSD: $1299
From the makers of the DirectStream DAC, which uses a field-programmable gate array (FPGA) in place of a dedicated DAC chip, comes the NuWave DSD, which does not. Instead, the more budget-minded NuWave DSD supplements an ESS Sabre32 Hyperstream chip with a complex programmable logic device (CPLD) that reclocks all incoming data and, in the bargain, reduces jitter (along with other laudable tasks). The NuWave DSD does PCM up to 192kHz via its USB and coax (RCA) inputs, and handles native DSD via its I2S input (via HDMI) and DoP DSD via USB, both to 5.6MHz. JCA, whose time with the NuWave DSD was unmarked by operational flaws, had considerable praise for the DAC's musical strengths, especially its rhythmic realism and impact: while listening to a favored piano recording, he noted that "the clicking of fingers on keys grabbed my attention as never before." Apart from observing a trivial rise in its noise floor while testing for intermodulation distortion, JA wrote that the NuWave DSD offers "respectable measured performance." (Vol.39 No.5 WWW) Rega Research DAC-R: $1195
This new iteration of the plain-named Rega DAC (the original was reviewed in Vol.34 Nos.5 & 10 and Vol.35 No.2) contains changes both small—the DAC-R's longer case (for better power-supply layout), and improved firmware and power connectors—and large: Rega's digital processor now has an XMOS-based, 24-bit/192kHz asynchronous USB input. The internal DACs are twin Wolfson WM8742 chips implemented without upsampling, allied to an output section built with discrete transistors. A choice of three user-selectable filters is offered, though the still-compact case—8.4" wide by 3.1" high by 12.5" deep—lacks a headphone jack. Using the Rega as an adjunct to his home recording studio, JI found that, while listening to vocal feeds, the DAC-R added a little sugar—"a slight warmth or sweetening"—that he didn't hear through his trusted Benchmark DAC2 HGC. (JI: "I liked it. The singer preferred it.") He also found that the DAC-R "produced a wonderful soundstage, floating aural images in space where they should be, with plenty of detail and depth." Apart from some artifacts that appeared related to the chipset's less–than–Gulag Archipelago degree of isolation from the power supply, JA's measurements suggest that the DAC-R "offered measured performance that was beyond reproach." Borderline Class A. (Vol.38 No.8 WWW)
C
Arcam rBlink: $250
The rBlink is a very small (2.9" W by 1" H by 3.9" D) Bluetooth audio receiver and digital-to-analog converter with RCA analog and S/PDIF coaxial outputs. It uses Arcam's implementation of CSR's audio-optimized aptX Bluetooth codec and a Burr-Brown PCM5102 DAC chip. Installation was simple and the Bluetooth sound was always easy to enjoy, said Sam. "Highly recommended," he concluded. JA's measurements of the rBlink suggest that its sound quality will very much depend on the codec used to stream audio data to it; the AAC codec appeared to preserve resolution at the expense of noise-floor modulation and enharmonic spuriae, while the aptX codec sacrificed absolute resolution in favor of preserving a random noise floor. Though data streamed via Bluetooth sounded somewhat brash and compressed vs that same data sent via a TosLink connection, the rBlink was surprisingly enjoyable, said JA. "Plug the Arcam's S/PDIF output into your high-end D/A processor and you have a convenient and legitimate source of music," he concluded. (Vol.36 No.12, Vol.37 No.3 WWW) K Bryston BDA-3, Chord DAVE, dCS Rossini, Meridian UltraDAC, Mytek Brooklyn, Lynx AES16e soundcard. Deletions
Halide Design DAC HD and USB-S/PDIF Bridge due to doubts over availability; CEntrance DACport LX, Mytek Stereo192-DSD-DAC discontinued; Apple AirPort Express, dCS Debussy not auditioned in a long time.
From the makers of the Class A–rated Zodiac Gold comes the Zodiac Platinum, which bundles a D/A processor, headphone amp, and preamp into a small but chunky (6.5" W by 4.4" H by 7.6" D) enclosure. (The similarly chunky Voltikus power supply is slightly less wide.) Like the Gold, the Zodiac Platinum offers PCM performance through 384kHz, but adds DSD64 and 128 via USB (DoP), which it upsamples to DSD256, Antelope Audio claiming direct DSD-to-analog conversion. Technical highlights include FPGA processing for some functions and "Oven-Controlled Clocking," in which jitter is kept low through thermal stabilization of the word clock's crystal oscillator. User controls appear on both the front panel and the remote handset, the former distinguished by a hefty, nice-feeling volume knob—although JI noted that it "produced a bit of a raggedy zipper sound" through his system when he adjusted the volume. With some musical selections JI noted the Platinum's "slightly thicker bottom end" compared with another premium processor, and with other tracks a thicker sound overall, adding that "both [processors] excelled at creating a transparent path to my power amps." As for the Zodiac's headphone amp, "I'd never heard better sound from my Grado HP1s," JI declared. JA wrapped up: "Overall, the very good measurements of Antelope Audio's Zodiac Platinum indicate excellent digital and analog engineering." (Vol.37 Nos.9 & 10 WWW)
The elegant-looking Vega D/A processor is housed in a slim, brushed-aluminum enclosure and has a front panel dominated by a wide, rectangular, yellow-on-black OLED display. The rear panel offers single-ended and balanced outputs, and five digital inputs: transformer-coupled AES/EBU on an XLR, two transformer-coupled coaxial S/PDIFs on RCAs, one optical S/PDIF on TosLink, and a high-speed USB2.0 port. The AES/EBU and S/PDIF inputs handle 16- and 24-bit data with sample rates up to 192kHz; the USB port also operates with sample rates of 352.8 and 384kHz, and will accept DSD64 and DSD128 data. A Sanctuary audio processor upsamples PCM input data to approximately 1.5MHz and 32-bit depth, and implements four reconstruction filters for PCM data and two choices of low-pass filter for DSD data. Though it required several hours from cold before sounding its best, the Vega combined outstanding low-end weight and high-frequency extension with an exceptional sense of space, said JA, who also noted measured performance that was beyond reproach. "It's DSD and digital done right!" he exclaimed. (Vol.37 No.2, Vol.38 No.11 WWW) Ayre Acoustics QA-9: $4750 ★
Housed in the same compact chassis as Ayre's QB-9 USB DAC, the QA-9 is a solid-state A/D converter intended to allow audiophiles to make high-quality rips of their LPs. It uses an Arda Laboratories AT1201 two-channel A/D converter chip and operates at sample rates up to 192kHz, outputting 24-bit data via either a USB 2.0 or AES/EBU connection. Setup was simple and, aside from the tedious task of eliminating LP surface noise, use was straightforward. The Ayre offered smooth highs, a clean midrange, and an excellent sense of space. JA summed up: "When recordings you love have never been issued on a good-sounding CD, it makes sense to rip them with Ayre's QA-9—it's the closest thing to a truly transparent audio component I have encountered." He bought the review sample. Now includes DSD and Word Clock outputs on transformer-coupled BNC jacks and outputs DSD via USB. (Vol.35 No.11, Vol.36 No.4 WWW) Ayre Acoustics QB-9 DSD: $3450 ★
The QB-9 is an asynchronous transfer mode, USB-input DAC with Ayre's minimum-phase digital reconstruction filter implemented in Field-Programmable Gate Array. It uses a Texas Instruments TAS1020B chip, supporting sample rates up to 96kHz and word lengths up to 24 bits. High-resolution digital files "popped with life" and were marked by a natural flow and physical impact that allowed WP to form a deeper emotional connection with the music. JA: "Ayre's QB-9 is well engineered, offering excellent performance in both the analog and digital domains, and is not compromised by its having just a USB data input." JI felt the QB-9 exceeded the YBA WD202 and Benchmark DAC1 USB in terms of spatial detail, depth, and width, while adding a touch of seductive clarity. "Wow!" The latest version of the QB-9 uses an XMOS XS-1 microprocessor chip and supports sampling rates via USB2.0 up to 192kHz. Earlier QB-9s can be upgraded for $250. Compared with the Resolution Audio Cantata, the Ayre tended to exaggerate sibilants on some recordings but provided a warmer, fleshier midrange, felt JI. Compared to the NAD M51, the Ayre had slightly greater punch and better dynamic edges. Compared to the much more expensive MSB Diamond DAC IV, the QB-9 had a very slightly more aggressive midrange, but otherwise held its own, said JI. Current production as of mid-2013, auditioned by AD in connection with his AX-5 review in Vol.36 No.7, uses an ESS Sabre DAC chip, offers improvements to the USB chip power supply, and will decode DSD data. Stereophile's "Joint Digital Source" and "Overall Component" of 2009. (Vol.32 No.10, Vol.33 No.6, Vol.34 Nos.7 & 11, Vol.35 Nos.7 & 10, Vol.38 No.11 WWW)
Although similar in appearance to previous Benchmark models, with a front-panel volume control and two 1/4" headphone jacks, the new DAC2 HGC uses four 32-bit ESS Sabre DACs, run in balanced configuration, for a significantly lower noise floor; has a new Hybrid Gain Control (HGC) for volume attenuation, which combines active analog gain control and passive low-impedance attenuators in the analog realm with a 32-bit digital DSP gain control for digital signals; and provides front-panel displays for both sample rate and word length. Though it lacks a balanced AES/EBU input, the DAC2 HGC offers two analog inputs and five digital inputs: two optical, two RCA coaxial, and one asynchronous USB that handles resolutions up to 192kHz as well as DSD64. It had a pleasantly forward sound, with smooth highs, a solid bottom end, and excellent image separation, said EL. Compared to the Auralic Vega, the Benchmark had a similarly smooth top end, but lacked the Vega's sweet midrange and outstanding portrayal of space, said JA. JI noted the DAC2's good scale and sense of ambient space, but found it lacked focus compared to the considerably more expensive MSB Analog DAC. (Vol.37 No.2, Vol.38 No.11, Vol.39 No.10 WWW) Bricasti Design M1 DAC: $8995 ★
With first-class fit'n'finish and uncluttered exterior design, the dual-mono M1 DAC measures a rack-friendly 17" W by 2" H by 12" D and weighs 12 lbs. It offers four digital inputs (S/PDIF, AES/EBU, BNC, optical), accepts sampling rates up to 192kHz, and, as of 2013, adds a USB input, volume control, remote control, and DSD decoding. The Bricasti's fast, detailed, powerful sound made the much less expensive Musical Fidelity M1DAC seem veiled, muffled, and slow, said JM. "The best digital playback I have heard," he concluded. Compared with the Weiss DAC202, the Bricasti was less forgiving of poorly recorded material, but had bigger, deeper, better-defined low frequencies; compared with the dCS Debussy, the Bricasti sounded very slightly warmer and was very slightly more transparent, said JA, who also praised the M1's state-of-the-art measured behavior. A firmware update (free to registered owners) adds minimum-phase digital filter options, digital phase inversion, and a digital volume control. Compared to its previous filter set, the Bricasti's minimum-phase sound was much richer, with more body, more coherence, and less grain, said JM. Used as a line source in place of Parasound's Halo JC 2 preamp, the Bricasti produced a more coherent sound, with deeper, tighter, more powerful bass. "My personal best just got better," JM concluded. Now ships with asynchronous USB input (not yet auditioned), and will decode DSD data. Production in 2013 replaces the switch-mode power supply of the M1's digital-routing section with a linear supply based on a custom-wound transformer. With the new power supply in place, JM heard improved bass extension and greater overall clarity. Owners of original M1s (made prior to March 2013) can have their units updated for $200. In 2014, Bricasti offered to M1 owners even more additional refinements: a remote-control kit, involving a separate infrared receiver that plugs into the rear panel ($500 for M1s presently in service; included in the price of new units); a changeover, performed at the factory, from multiple glass-and-wire fuses to a master circuit breaker ($150); and an upgrade, also done at the factory, to DXD and DSD64/DSD128 capabilities ($400). As impressed as he was by the last, JM remained philosophical: "the fact that Bricasti's M1 can now play DSD and DXD files is less important than the fact that its playback of plain old 'Red Book' 16-bit/44.1kHz audio is so compelling that I, for one, don't feel shortchanged when a good recording is not 'high-resolution.'" He observed that, yet again, his personal best in digital playback just got better. (Vol.34 No.8; Vol.35 Nos. 2, 3 & 9; Vol.36 No.7; Vol.37 No.12 WWW) exaSound e28 Mk.2 multichannel DAC: $3299
See "Music Surround-Sound Components" (Vol.36 No.11 WWW) Grace m905: $3495
From the pro-audio world comes the Grace Designs m905 Monitor Controller: a combination line stage, D/A converter, and headphone amplifier designed as a control center for music playback in a recording studio. As befits its provenance, the m905 is rack-mountable, with most of its controls built into an umbilical-connected, iPad Mini–sized remote that, according to JM, exuded an "Authentic German Engineering" level of quality, even though Grace Designs is based in Colorado. The m905 is built around the Burr-Brown PCM1798 DAC chip, plus an XMOS USB receiver, and it offers, via the DoP standard, DSD streaming: the first product from Grace Designs to do so. Already a fan of the "ever-so-slightly euphonic" Grace m903—which was Stereophile's Headphone Product of the Year for 2012—JM was "taken aback at how much better the m905 sounded," and quantified the depth of his delight at the new model's DSD capabilities with two words: "Woober Joobers!" He said that, all in all, the m905 is "among the most impressive pieces of audio gear" he has ever evaluated. (Vol.37 No.4 WWW)
Among the earliest and most notable products to emerge from the burgeoning world of DSD streaming, the Luxman DA-06 is a full-size D/A processor built around a Burr-Brown PCM 1792A 32-bit converter chip. The DA-06 supports 2.8224 and 5.6448MHz DSD files and, via its USB input, PCM files up to 32-bit/384kHz. Front-panel controls include the ability to select among three different PCM filters and between two sets of DSD rolloff characteristics, as well as to invert absolute signal polarity on the fly. AD, who acknowledges "DSD's prowess at communicating the subtleties of musical flow," observed that the Luxman sounded "generously explicit, [with] musical and sonic details in abundance and . . . a soundfield notable for its openness and general lack of murk. Still, the DA-06 had good substance, with a tonal character that was slightly—almost imperceptibly—warm and round." In his measurements, JA noted that the Luxman's low levels of harmonic and intermodulation distortion are offset somewhat by marginally poorer-than-expected jitter and noise-floor numbers—yet he declared that, overall, "the DA-06's measured performance is simply superb." AD's conclusion: "a damn fine-sounding D/A converter with virtually all music." (Vol.37 No.7, Vol.38 No.11 WWW) Moon by Simaudio Evolution 780D: $15,000
Compared with Simaudio's Moon Evolution 650D and 750D transport-converters, the new Evolution 780D does away with physical media altogether, forcing those who desire real-time CD playback to use an external transport or a CD player with digital outputs. That said, also in comparison with the company's previous processors, the 780D adds both processing power—it can handle PCM files up to 384kHz and DSD up to 11.2896MHz, and its femtosecond clock is claimed to produce lower jitter—and power power: the 780D features the company's Moon Hybrid Power (MHP) power supply, with conductive polymer capacitors and other refinements. The 780D also includes Simaudio's Moon intelligent Network Device (MiND), a music-streaming application accessible via Ethernet or built-in WiFi. MF described the new Moon's improvements over the 650D as sounding "evolutionary rather than revolutionary"; however, when used with the best recordings at hand, "the 780D's transparency and graceful yet superbly detailed transient performance combined with an absence of . . . digital artifacts to produce what was among the most transparent, if not the most transparent digital sound I've heard." MF also observed that the 780D's manual is insufficiently helpful, especially regarding the MiND application, and that the product lacks, at least for now, support for Roon or MQA. JA uncovered nothing but "superb measured performance." (Vol.39 No.8 WWW) MSB Analog DAC: $6995
The MSB Analog DAC combines a high-tech chassis machined from a solid billet of aluminum—it stands less than 1" tall yet weighs nearly 30 lbs!—with a circuit architecture that allows the buyer to select among five digital-input options, two power supply options, a WiFi option, and more—combinations of which can bring the price to just under $12,000. (For $6995, you get one digital input and the stock power supply.) The Analog DAC supports PCM and DSD up to 384kHz, employs a custom-designed, linear-phase apodizing digital filter, and offers single-ended and balanced analog outputs. JI was impressed with the MSB's "thereness," observing that, "With a DAC like the MSB, you get a sense of someone hitting Play on a big reel of wide-track analog tape, after being fed by live mikes in a room." Notwithstanding a couple of performance glitches, both solved by in-the-field firmware updates, JI found it difficult to part with his review sample: "It notched my system up to a place where almost all digital sources had an organic, natural presence without sacrificing the accuracy and detail present in the best recordings." JA noted that high-level signals produced some low-level distortion products, but otherwise found the MSB rare in being "so well thought out and so well engineered." Optional Volume Control: $995. Optional Analog Power Base: $2995. UMT Plus: $5995. Optional Dual Signature Power Base: $4995. (Vol.37 No.4 WWW)
The M51 is an attractive, full-width D/A converter with a digital volume control and useful front-panel vacuum-fluorescent display that indicates input, volume status, and sampling rate. It offers AES/EBU, coaxial, optical, USB, and two HDMI inputs, as well as analog (one pair each single-ended and balanced) and digital (HDMI) outputs. While all of the NAD's inputs can handle PCM audio data of resolutions up to 24-bit/192kHz, the M51 converts everything it receives to a pulse-width-modulation (PWM) signal at a sampling rate of 844kHz, controlled by a clock running at 108MHz. The NAD had a "wonderfully detailed and revealing sound," said JI. JA noted measured performance that was "almost beyond reproach." Compared to the Auralic Vega, the NAD produced a cleaner, leaner, airier, less forgiving sound, said JA, though he still highly recommends the M51 as a great value for the price. Readers have reported—and JA has now confirmed—that the M51's earlier v.1.39 firmware offers a better, "fatter" sound than the later v.1.41, probably due to a 1dB higher output; later versions of the M51 can be easily "rolled back." to v.1.39. (Vol.35 No.7; Vol.37 Nos.2 & 5 WWW) PS Audio PerfectWave DirectStream: $5999
Instead of an off-the-shelf chipset, PS Audio's first DSD processor uses original code written by hand into a field-programmable gate array (FPGA)—the result being a system that converts all incoming data to double-rate DSD. In addition to asynchronous USB, digital inputs include RCA, TosLink, and HDMI, and both single-ended and true balanced analog outputs are provided. The DirectStream is built on a cast-alloy chassis with a glossy MDF top—and a touchscreen from which all user controls can be worked. (A remote handset is included.) Firmware is user-updatable, as AD discovered while reviewing the DirectStream—during which time he noted its "excellent pacing, flow, correctness of pitch relationships, and the like, as well as a consistently smooth and slightly laid-back sound." With some files, AD found the DirectStream just a little too laid-back—a condition mitigated in part by that firmware update—but found its musicality beyond reproach. JA observed that the DirectStream "measures superbly well" in many ways, but was troubled by its poor linearity at low frequencies and its "ultimate lack of resolution" with hi-rez files. But he admits that its sound quality is still very satisfying. In his Follow-Up, RD—whose listening is centered more around discs than downloads—tried the DirectStream DAC with PS Audio's PerfectWave Memory Player transport ($3995), and observed, "listening to familiar recordings . . . I heard more musical detail from them than I previously had. This detail was not a matter of exaggerated treble, which can give an impression of increased detail, but was genuinely higher resolution manifested by greater differentiation among the sounds of instruments and rhythmic patterns." Subsequent to that audition, RD received and installed in the DirectStream DAC a new firmware upgrade that brought his unit to v.1.2.1. His verdict: "The latest firmware represented a major improvement over the one that I and Art Dudley and Michael Lavorgna had. Soundstages were now deeper and wider, and well outside the speakers' positions with some recordings; and images on those stages were now more 'rounded,' more three-dimensional. The bass was cleaner, with better-defined transients." Following the firmware update to v.1.2.1, JA retested the DirectStream DAC and found a lower noise floor, increased low-level linearity, and a dramatic reduction in low-frequency distortion. Said JA: "Kudos to PS Audio for designing a product so that its performance can so easily be upgraded by its customers." Four months after the upgrade to v.1.2.1, PS Audio updated the DirectStream DAC's operating system to a version referred to as Pike's Peak—which, in RD's estimation, "seemed to transform the . . . sound: more dynamic, better bass, more extended treble, even better soundstaging." Writing in a subsequent Follow-Up, RD reported on PS Audio's more recent Yale software upgrade, said to include more accurate filters and to represent a different approach to jitter reduction. He said that, in comparison with Pike's Peak, Yale offered slightly softer trebles and was "more subtly detailed"; he concluded that Yale is the superior operating system. (Vol.37 No.9, Vol.38 Nos. 2, 3, 5, 11 WWW) T+A DAC8 DSD: $3995
See JI's review in this issue. TotalDAC d1-tube-mk2: 9100
In a design field where cats are skinned in any number of ways, Vincent Brient of the French company TotalDAC takes a distinctive approach: for his D/A converters, he uses a discrete R2R ladder comprising some 200 hand-selected, very-high-quality discrete resistors per channel. The nonoversampling d1-tube-mk2 supplements this circuitry with an FPGA for various digital chores, an XMOS USB receiver (S/PDIF, TosLink, and AES/EBU digital inputs are also provided), and a tubed output stage. DSD (DoP) compatibility is a 320 option. All inputs support 24-bit/192kHz resolution except TosLink, which maxes out at 24/96. In the experience of ML, to whom digital recorded sound manifests itself as a sheet of glass between himself and the performers, "listening to music through the TotalDAC d1-tube-mk2, there was no glass; I could listen to my music as deeply as I wanted to go." Which pretty much says it all. (Vol.39 No.1 WWW)
In common with other Audio Note D/A converters and CD players, the DAC 2.1x Signature is built around a rather old-school 18-bit Analog Devices 1865 chip, said to be hand selected. Neither oversampling nor digital filtering is used, nor does the DAC 2.1x Signature contain an analog filter; according to Audio Note, the converter's use of a transformer as an I/V stage confers on the output signal sufficient treble rolloff. The tubed output stage is built with Audio Note's own copper-foil-in-oil signal capacitors, and signal output is handled by Audio Note Silver interconnect cable. Digital inputs are limited to S/PDIF (RCA) and AES/EBU (XLR); a USB input is not offered. After using it with Audio Note's own CDT One/II disc transport, AD praised the DAC 2.1x Signature for its sonic heft and substance, its analog-like momentum and flow, and, overall, a knack for "bringing out the goodness of good recordings, [although it] also had a knack for accentuating the badness of certain types of bad recordings." While testing the DAC 2.1x Signature, JA discovered distortion products, noise, jitter, and data truncation (24 to 18 bits), leading him to describe the Audio Note as "broken." (Vol.39 No.1 WWW) Benchmark Media Systems ADC1 USB: $1795 $$$
Housed in the same small case as Benchmark's DACs, the ADC1 is a 24-bit USB A/D converter with a Texas Instruments TAS1020B USB chip and a 128x-oversampling, delta-sigma AKM 5394 A/D converter chip. It offers a pair of balanced analog inputs on XLRs, two unbalanced AES/EBU Aux outputs on BNC jacks, a USB Type-B port, a Main TosLink output working in either S/PDIF or ADAT format, a Main balanced AES/EBU output on an XLR, and word-clock input and output on BNCs for use in multichannel systems, slaved to other converters. Though it lacked the Ayre Acoustics QA-9's delicately drawn soundstage, the Benchmark produced a natural, coherent overall sound, with clean high frequencies and weighty, extended lows, said JA, who also noted superb measured performance. (Vol.37 No.2 WWW) Cambridge Audio Azur 851D: $1649 $$$
Designed in the UK and manufactured in China, the Cambridge Azur 851D DAC-preamplifier is well-finished and somewhat surprisingly solid for its price range. It upsamples everything to 24-bit/384kHz, and most of its inputs can handle 24/192 datastreams. The Azur 851D also has a headphone jack, three switchable filter settings, a choice of balanced and single-ended outputs—and, for the fun of it, Bluetooth wireless connectivity. It also has a sophisticated user interface, addressable by both its menu-driven front-panel controls and its comprehensive remote handset. In JI's words, "the Cambridge Audio Azur 851D has bang for the buck all over the place. It approached the sound of DACs costing four times as much—closely enough, I feel, to satisfy most audiophiles on a budget." After the 851D left his test bench, JA observed, "The Cambridge Audio Azur 851D's measured performance is never short of superb. The fact that it can offer this level of performance for $1500 puts many more-expensive processors to shame." In his Follow-Up, AD was put off by the Azur's "needlessly complex" control panel, but impressed all to hell and back by its musicality: "The Cambridge 851D is, indeed, a killer of giants. It is a D/A converter that uses its high resolution not to add amusical filigree or spatial puffery, but to enhance musical flow and drama. It really is that good. (Vol.37 No.12, Vol.38 No.2 WWW)
Chord's Hugo TT (for Table Top) combines a DSD-friendly USB DAC, headphone amplifier, and Bluetooth receiver in one distinctly styled and unambiguously chunky aluminum case. The user interface is distinguished by a volume control that uses not a knob or a pair of buttons but rather a captured glass marble that changes color as the loudness level changes, and a top-panel lens that gives the user a clear view of the color-coded sample-rate indicators inside. Key to the Hugo's performance are an internal chargeable battery—for power-supply isolation, not portability—and a field-programmable gate array (FPGA) running Chord's proprietary filter algorithms. Both on its own and in comparison with other DACs of his acquaintance, JI identified the Hugo's strengths as "detail, definition, and depth, with no distracting artifacts." He also declared: "The Chord Hugo TT sounded wonderful with headphones." In a dispatch from his test bench, JA said the Hugo "performed superbly well" on his jitter tests and was, all around, "an extraordinarily well-engineered component." (Vol.38 No.11 WWW) Lector Strumenti Digitube S-192: $3195
The full-width (16.9") Lector Strumenti Digitube S-192, which AD described as well built and well styled "without silly excess," is a D/A converter whose only user control, apart from its power switch, is a pushbutton that selects among its five digital inputs: RCA, BNC, TosLink, XLR (for AES/EBU), and USB. Its Japanese AK4397 DAC chip provides 32-bit performance at up to 192kHz, and it has an analog (non-switching) power supply and, in its analog output section, a pair of ECC81 dual-triode tubes. Using the Digitube primarily as a USD processor with his iMac and his decidedly tube-friendly music system, AD found that it offered "a near-analog portrayal of . . . colors and textures" and excellent impact and detail resolution, although its sense of scale was bested by the far less expensive Halide DAC HD. Yet in measuring the Digitube, JA noted "truly dreadful measured performance in the digital domain, along with [a] disappointing showing in the analog domain"—in light of which, greater-than-usual buyer circumspection seems appropriate. "Class A, for special tastes only," sums up AD. (Vol.37 No.6 WWW) M2Tech Young DSD: $1399 ★
Elegant and modern in appearance, the M2Tech Young is a DC-powered D/A processor with a simple aluminum case, a recessed front panel, and a large alphanumeric display. It uses a Burr-Brown PCM1795 DAC chip with a custom oversampling minimum-phase filter. It handles resolutions up to 32 bits via USB (24 bits via S/PDIF or AES/EBU), and sample rates up to 384kHz via USB (192kHz via S/PDIF or AES/EBU). While the Young lacked some accuracy and precision, it nevertheless managed an excellent balance of detail and warmth, said JI. Review was with the Palmer Power Station battery power supply, now replaced by the Van der Graaf low-noise power supply ($1199). Adding the Palmer resulted in significantly more focus and clarity. "The M2Tech combo seduced me," JI concluded. Current version will decode DSD128. (Vol.36 No.5 WWW)
Intended as a replacement for their V-DACII—itself one of ST's longtime reference components—Musical Fidelity's V90-DAC is housed in the same 6.6" by 4" by 1.8" brushed-aluminum case that characterizes the rest of the V90 line. This 24-bit converter, which uses a 32-bit Burr-Brown PCM1795 DAC chip, delivers up to 192kHz performance through its single coaxial (RCA) input and up to 96kHz through its USB and two optical TosLink inputs. According to ST, compared with its predecessor, "the V90-DAC offers still greater low-level resolution, superior dynamics, and fatigue-free listening." JA took the V90-DAC for a spin, going so far as comparing it with his current reference, the Auralic Vega. He noted the MF's combination of smoothness, naturalness, and detail, combined with good spatial properties—but he felt the V90-DAC was lacking, by comparison, in momentum and bass power. JA's measurements uncovered "a strange rise in the noise floor around the 19 and 20kHz tones, in only the right channel"; otherwise, the V90-DAC "definitely punched above its weight on the test bench." (Vol.37 Nos. 4 & 8 WWW) B CEntrance DACport: $199 ★
USB bus-powered D/A processor with volume control. See "Headphones & Headphone Accessories," where it is rated Class B. Used as a single-input preamp between a laptop source and a pair of Rogue M180 monoblocks in EL's main system, the DACport produced a large soundstage, a slightly rolled-off but grain-free treble, and a tube-like midrange. Compared to the Benchmark DAC1 HDR, the DACport lacked resolution and bass weight, but always sounded musical and tonally balanced. LX version sounds clearer, more transparent, and is rated Class B as a D/A processor. (Vol.33 Nos.6 & 10 WWW) Channel Islands Audio Transient Mk.II: $699
Housed in a small (4.45" W by 2.9" H by 5.25" D), nicely finished aluminum case, the Transient Mk.II is an asynchronous USB DAC with a 24-bit volume control and three digital outputs: S/PDIF via 75-ohm BNC, I2S via mini-DIN, and differential I2S via an HDMI jack. Six front-panel LEDs indicate the incoming signal's sampling rate: 44.1, 48, 88.2, 96, 176.4, or 192kHz. In a case identical to the Transient's, the optional VDC5 Mk.II high-current power supply ($329) feeds the Transient a linear 5V DC at 2.5A for reduced noise and ripple. Though it lacked some high-frequency focus and ease, the Transient Mk.II produced a well-balanced overall sound, with good soundstage size, respectable bottom-end heft, and a clean midrange, said JI. Measured performance was somewhat disappointing, however; JA found that, even with 24-bit data, the Transient offered resolution of just over 17 bits. (Vol.37 No.3 WWW)
iFi Audio is a subsidiary of Abbingdon Music Research. The iDAC, iFi's first product, is a sleek, single-box D/A converter built into a 6"-long aluminum extrusion with an attractive textured finish. It uses an ESS Sabre DAC chip capable of handling resolutions up to 24-bit/192kHz, and has a single USB-B input, a pair of RCA jacks for line output, and a 3.5mm headphone jack with volume control. It can be powered by the user's computer or by iFi's iUSBPower 5V power supply ($199). Compared with the AudioQuest DragonFly, the stock iDAC had a better overall sense of touch on strings and percussion, and revealed greater richness and complexity in hi-rez music files, said AD. With the iUSBPower powering the iDAC, Art noted a subtly clearer sense of force in note attacks and better spatial presence around voices. "Highly recommended," he concluded. (Vol.36 No.5 WWW) PS Audio NuWave DSD: $1299
From the makers of the DirectStream DAC, which uses a field-programmable gate array (FPGA) in place of a dedicated DAC chip, comes the NuWave DSD, which does not. Instead, the more budget-minded NuWave DSD supplements an ESS Sabre32 Hyperstream chip with a complex programmable logic device (CPLD) that reclocks all incoming data and, in the bargain, reduces jitter (along with other laudable tasks). The NuWave DSD does PCM up to 192kHz via its USB and coax (RCA) inputs, and handles native DSD via its I2S input (via HDMI) and DoP DSD via USB, both to 5.6MHz. JCA, whose time with the NuWave DSD was unmarked by operational flaws, had considerable praise for the DAC's musical strengths, especially its rhythmic realism and impact: while listening to a favored piano recording, he noted that "the clicking of fingers on keys grabbed my attention as never before." Apart from observing a trivial rise in its noise floor while testing for intermodulation distortion, JA wrote that the NuWave DSD offers "respectable measured performance." (Vol.39 No.5 WWW) Rega Research DAC-R: $1195
This new iteration of the plain-named Rega DAC (the original was reviewed in Vol.34 Nos.5 & 10 and Vol.35 No.2) contains changes both small—the DAC-R's longer case (for better power-supply layout), and improved firmware and power connectors—and large: Rega's digital processor now has an XMOS-based, 24-bit/192kHz asynchronous USB input. The internal DACs are twin Wolfson WM8742 chips implemented without upsampling, allied to an output section built with discrete transistors. A choice of three user-selectable filters is offered, though the still-compact case—8.4" wide by 3.1" high by 12.5" deep—lacks a headphone jack. Using the Rega as an adjunct to his home recording studio, JI found that, while listening to vocal feeds, the DAC-R added a little sugar—"a slight warmth or sweetening"—that he didn't hear through his trusted Benchmark DAC2 HGC. (JI: "I liked it. The singer preferred it.") He also found that the DAC-R "produced a wonderful soundstage, floating aural images in space where they should be, with plenty of detail and depth." Apart from some artifacts that appeared related to the chipset's less–than–Gulag Archipelago degree of isolation from the power supply, JA's measurements suggest that the DAC-R "offered measured performance that was beyond reproach." Borderline Class A. (Vol.38 No.8 WWW)
The rBlink is a very small (2.9" W by 1" H by 3.9" D) Bluetooth audio receiver and digital-to-analog converter with RCA analog and S/PDIF coaxial outputs. It uses Arcam's implementation of CSR's audio-optimized aptX Bluetooth codec and a Burr-Brown PCM5102 DAC chip. Installation was simple and the Bluetooth sound was always easy to enjoy, said Sam. "Highly recommended," he concluded. JA's measurements of the rBlink suggest that its sound quality will very much depend on the codec used to stream audio data to it; the AAC codec appeared to preserve resolution at the expense of noise-floor modulation and enharmonic spuriae, while the aptX codec sacrificed absolute resolution in favor of preserving a random noise floor. Though data streamed via Bluetooth sounded somewhat brash and compressed vs that same data sent via a TosLink connection, the rBlink was surprisingly enjoyable, said JA. "Plug the Arcam's S/PDIF output into your high-end D/A processor and you have a convenient and legitimate source of music," he concluded. (Vol.36 No.12, Vol.37 No.3 WWW) K Bryston BDA-3, Chord DAVE, dCS Rossini, Meridian UltraDAC, Mytek Brooklyn, Lynx AES16e soundcard. Deletions
Halide Design DAC HD and USB-S/PDIF Bridge due to doubts over availability; CEntrance DACport LX, Mytek Stereo192-DSD-DAC discontinued; Apple AirPort Express, dCS Debussy not auditioned in a long time.
