Even with a worldwide economic downturn, and five years into a slow recovery, it’s still a great time to be an audiophile. While amplification and loudspeaker technologies have shown steady, incremental improvement, source technologies, especially digital reproduction, continue to advance at a breakneck pace even as the overall cost continues to decline. Just five years ago, as CD sales retreated to the ash heap of history and SACD and DVD-A languished in the marketplace, lossy MP3s appeared to be the format of a dismal sonic future. Since then, I and many others have abandoned discs to happily embrace music servers that can stream lossless and high-resolution music files to DACs capable of reproducing music in all the popular bit depths and sample rates. Today there are DACs at all price points, ranging from a few hundred dollars to the cost-no-object level.

While a budget DAC may be a great way to start, or may be suitable for a desktop system, any real gains in sound quality will be at midrange or higher prices, with a sizable sweet spot in the upper middle range. Notable DACs for under $10,000 USD include models from Berkeley Audio Design, Bricasti, Calyx, and my current reference, Meitner Audio’s MA-1 ($7000).

Esoteric has made a name for itself in perfectionist audio, and I’ve had the pleasure of reviewing two of their integrated amplifiers. My first exposure to an Esoteric product was ten years ago, when the DV-50 universal disc player was launched. I really wanted to buy one, but held off because of uncertainty in the direction of the market. So, when I was offered the opportunity to evaluate Esoteric’s D-07X DAC ($5000), my answer was a resounding “Yes!”

Design

The D-07X is a 32-bit, dual-mono DAC; it’s an update of the D-07 DAC, reviewed by Vade Forrester in August 2010. But while the D-07’s S/PDIF, AES/EBU, and optical inputs could handle resolutions of up to 24-bit/192kHz, its asynchronous USB input was restricted to an upper limit of 24/96. This has been rectified in the D-07X -- with a driver downloaded from Esoteric’s website, the D-07X’s USB input can deal with resolutions up to 24/192. The D-07X can serve as a DAC for a server-based system, and can also be linked to an Esoteric SACD/CD player via its AES/EBU input.

The heart of the D-07X is its 32-bit AK4392 chipset, with two circuits per channel in parallel/differential output configurations to provide greater linearity and lower noise. The converter chips and the analog outputs are completely separated, for excellent channel separation. The high-quality buffer circuits used in the final output stage are laid out symmetrically, allowing for a fully balanced circuit.

The substantial power supply comprises an extra-large, low-loss, R-core transformer with low leakage of magnetic flux, large capacitors, and a high-speed Shottky diode. Esoteric claims that this supply ensures stable power to all circuits. A high-precision, voltage-controlled crystal oscillator is used for the internal clock, to reduce jitter and improve imaging and soundstaging.

The D-07X can be used in its Digital Filter Off mode or with one of its four filter modes engaged: two finite-impulse-response filters and two apodizing filters. All filters are claimed to eliminate pre-echoes for a more natural sound.

The handsome D-07X is built to Esoteric’s usual rugged standard, with a substantial chassis and case that mimic their other models. The D-07X measures 17.5”W x 4.25”H x 14.1”D and weighs a solid 23 pounds. Its sculpted front panel has a central, recessed LED display that glows fluorescent blue and shows the selected input and output, the sampling frequency, and the volume level; to the right of this is the headphone jack. On the front panel’s far left is the backlit power button; to the right of this is the Clock indicator, and below that the Menu button. To the immediate right of the display is the Input selector, and on the far right are the Volume - and + buttons. All of these functions are also accessible with the supplied remote control.

On the left of the rear panel are pairs of RCA and XLR analog outputs for each channel, plus an input and output for an external synchronizing clock. Above these are arrayed, from left to right, the USB, TosLink, RCA, S/PDIF, and AES/EBU digital inputs. On the far right is an IEC jack for the supplied, detachable power cord.

Setup

Unlike my Meitner MA-1 DAC, which is completely plug-and-play, the D-07X requires use of its Menu and Input controls to select the desired input and output. This was straightforward; once I’d selected the USB input and XLR output, I checked to see that my Mac Mini’s Audio MIDI menu had recognized the D-07X, which it had. I was ready to roll.

Since my integrated amplifier has no preamp bypass, I didn’t use the D-07X’s volume control. Also, I left the Esoteric in the recommended Digital Filter Off mode. While I did try the D-07X’s headphone output, I didn’t use it enough to evaluate its quality, though it seemed to play well without any difficulty.

The D-07X performed flawlessly throughout the listening period.

Sound

Tim Crable, of TEAC North America, recommended that I give the D-07X about 300 hours of burn-in before doing any serious listening. I did give it a few weeks’ use before beginning my critical evaluation, but just as I’d done with Esoteric’s I-03 integrated amplifier last year, I put the D-07X through the full battery of Cardas and Ayre Acoustics’ Irrational, But Efficacious! system-enhancement disc. Unlike with the I-03, I heard little to no change in the D-07X’s sound following this treatment, nor did I hear any difference for the duration of the listening period.

The sound of the D-07X was consistently engaging regardless of musical genre, quality of recording, or bit depth and sample rate -- but, as with Esoteric’s I-03 integrated, the D-07X sounded best with acoustic music, particularly classical and jazz. As a result, almost all of my listening was to non-amplified music. That’s not to say that amplified music was at a disadvantage, but the D-07X clearly excelled with acoustic music. Classical music makes up about 10% of my day-to-day listening, but the D-07X almost demanded that I listen to more of it. I obliged with long late-night sessions of listening -- particularly to large-scale orchestral works, which sounded just gorgeous. Instrumental textures and harmonic overtones and undertones were fully fleshed out by the D-07X, and rhythm and tempo were spot on. Because of the Esoteric’s transparency, instrumental details and subtle sonic cues were highlighted, which tightened the music’s emotional grip on me.

I recently purchased a high-resolution set of Beethoven’s nine symphonies with Daniel Barenboim conducting the West-Eastern Divan Orchestra (24/96 AIFF, Decca/HDtracks). While the basic tempo of this version of Symphony No.5 is a bit sluggish for my taste, the essential drama of the work was captured by the D-07X, with a weight and thrust that were appropriately conveyed.

While not exceptionally wide, the D-07X’s soundstage was very deep, and one of the best I’ve heard in my room. The timpani that begin Aaron Copland’s Fanfare for the Common Man, with Zubin Mehta conducting the Los Angeles Philharmonic (16/44.1 AIFF, London), were set far deeper than I’m used to hearing, but remained reverberant, with no diminishment in impact. Often with this recording, these drums sound unrealistically forward compared to the instruments’ usual placement during a concert.

The D-07X’s tonality was somewhat cooler than I usually prefer, but this was noticeable only immediately after I’d switched from my Meitner MA-1 -- a few minutes later, as my aural memory faded, that quality wasn’t apparent. In that respect, amplified music had some advantage over acoustic music, as this quality was far less noticeable.

With smaller ensembles, such as jazz piano trios, quartets, and quintets, there was great separation of instruments and a sense of space between the players, especially with classic recordings from the 1950s and ’60s. In “Blue in Green,” from Miles Davis’s Kind of Blue (16/44.1 AIFF, Columbia/Legacy), John Coltrane’s tenor saxophone solo floated in front of the rest of the players with a vibrancy and burnished tone that belied the age of this 54-year-old recording.

With more modern recordings, such as Chick Corea, Stanley Clarke, and Lenny White’s Forever (24/96 AIFF, Concord Jazz), the sound was pristine, with great clarity and ease of flow. In the opening track, a cover of Stevie Wonder’s “Overjoyed,” Corea’s piano, Clarke’s bass, and White’s drums were woven into a tapestry of sound that still allowed individual flourishes to shine.

Although I spent most of my time with the D-07X listening to acoustic jazz and classical, I didn’t give pop or rock short shrift. Recent additions to my collection include hi-rez downloads of the David Lee Roth-era Van Halen (sweet!) and the entire Rush catalog (überawesome!). “Drop Dead Legs,” from 1984 (24/192 AIFF, Warner/HDtracks), is up there with “Unchained” as one of my fave Van Halen tunes. In the instrumental fade, Eddie Van Halen rips out a pyrotechnic riff that Michael Anthony and Alex Van Halen anchor with steady rhythmic drive -- the D-07X held it all together with no edge or loss of bass impact.

I not only listened to these recordings streamed from my hard drive, but also via a paid Spotify subscription, which is ad-free and streams at a higher quality. While considerably less dynamic, and with a more compressed soundstage than my server library, it was still pleasurable via the D-07X.

Comparing the Esoteric and my Meitner DAC was interesting. I mentioned earlier that I felt the D-07X sounded cooler than the MA-1. However, I feel that this is how Esoteric has voiced the D-07X -- I noticed a similar quality with their I-03 integrated amplifier, which I reviewed with a different set of speakers. It should be noted, though, that this is far from a deal breaker, and was far less noticeable with the D-07X than I remember hearing from the I-03.

The two DACs exhibited similar levels of transparency and smoothness of treble, though the Meitner had a little more top-end air. Their low-end performance was also comparable, with supple, tight bass; I could hear no significant differences. With soundstaging, it was a bit of a draw. The D-07X excelled at depth, while the MA-1 beat it handily with width.

Conclusion

Esoteric’s D-07X is a full-featured DAC from a proven manufacturer with a reputation for technical R&D and excellent sound. It is fully competitive with other well-regarded DACs costing less than $10,000, including my reference Meitner MA-1 ($7000). I feel you can’t go wrong with the D-07X -- it should be on anyone’s list for consideration. If you listen mostly to acoustic jazz or classical music, it may be all the DAC you’ll ever need.

. . . Uday Reddy
udayr@soundstagenetwork.com

Associated Equipment

• Loudspeakers -- Revel Ultima Salon2, Audioengine A2
• Integrated amplifier -- Jeff Rowland Design Group Concentra
• Digital sources -- Meitner Audio MA-1 DAC; Apple Mac Mini running OS 10.7.5, iTunes 10.6.1, Audirvana Plus v1.5.5, remote-controlled using screen sharing via iMac OS 10.7.5; Devilsound USB DAC
• Interconnects -- Cardas Audio Neutral Reference XLR and RCA, Cardas Clear USB, Halide Design S/PDIF asynchronous USB Bridge with BNC termination
• Speaker cables -- Cardas Audio Neutral Reference
• Headphones -- Sennheiser HD 600 with Cardas cable upgrade, Ultimate Ears UE 11 Pro, Ray Samuels Audio Emmeline The Predator headphone amplifier
• Accessories -- Audio Power Industries Power Pack II power conditioner; Cardas Twinlink and Cardas Cross power cords; Cardas Audio Signature XLR, RCA, and BNC caps; Cardas/Ayre Acoustics Irrational, But Efficacious! system-enhancement disc

Esoteric D-07X Digital-to-Analog Converter
Price: $5000 USD.
Warranty: Three years parts and labor.

TEAC North America
7733 Telegraph Road
Montebello, CA 90640
Phone: (323) 726-0303

Website: www.esoteric.teac.com