The K-03X is Esoteric’s penultimate CD/SACD player. Similar in appearance to the significantly more costly Esoteric flagship K-01X, the K-03X represents a commanding presence. Built to a standard of quality and luxury that few players can match—from the exquisite three-point isolation footers to the buttery-smooth action of the aluminum disc tray, it’s a mechanical delight to observe in operation. The player’s vault-like construction and sixty-pound mass suggests a permanence of a millennial order. Seemingly immune to the ravages of time, it’s a veritable monument of brushed aluminum and steel plate that neither mechanical nor acoustic resonances or vibrations can breach. The K-03X is much more than a single-box disc player however; the dual mono design houses an independent, fully fledged and equipped high-resolution DAC that supports hi-res files over USB, SPDIF, and TosLink. Outfitted with four DACs per channel operating in parallel, there are dual oversize toroidal transformers that supply independent power to the digital and analog circuits for each channel.
The new “X” designation isn’t just for show either. It represents some serious upgrades over its predecessors, the K-03 and K-01 that colleague Alan Taffel reviewed in Issues 213 and 230 respectively. Chief among them is the new AK4495S DAC chipset, the same DAC that graces the über-flagship Grandioso series. Internal processing has also been upped to 34-bit from 32-bit. The DAC now supports DSD64 and DSD128 (double DSD) and 384kHz/32-bit PCM playback over USB and SPDIF. Additionally external clock sync is obtainable in USB DAC operation, a feature previously unavailable in the K-03. Esoteric’s Scott Sefton said, “It also has a new USB board supported natively by Mac OS X, so in addition to more functionality (DSD) it is simpler, at least for Mac users.” Finally, the variable-output level has been jettisoned, as Esoteric has deemed that the compromises inherent in digital volume controls were too restrictive on ultimate performance.
Back-panel connectivity includes both RCA and balanced XLR analog outputs along with accommodation for digital sources via USB, SPDIF, and TosLink inputs. These provide a level of flexibility that later permitted me to connect a trio of digital sources—a DVR, Apple TV, and a MacBook—without a hiccup. A remote control is included.
Internally the centerpiece of Esoteric’s spinning disc technology is the latest incarnation of the company’s famed VRDS drive mechanism. Purposefully designed to spin Super Audio CD discs, the VRDS-NEO VMK-3.5-10 is a high-precision, stable duralumin turntable that improves reading accuracy by mechanically correcting for surface run-out. This mechanism’s massive architecture and the 10mm-thick turntable bridge ups the unit’s weight to over nine pounds—and to more than 22 pounds including the rigid base. With the addition of its proprietary VS-DD spindle servo driver—previously offered only on Esoteric’s flagship players—smoother high-precision servo control and a more stable drive is attained. Finally, a discrete three-channel ampliﬁer circuit optimizes the waveform of the current supplied to the motor for quieter and smoother spindle operation. The whole package weighs in at a whopping 62 pounds.
During setup, attention must be paid to the K-03X’s front-panel “Mode” button. Beyond basic configuration—display, power saving, etc.—pressing that button unleashes a bevy of sound optimization options, four up-conversion picks (2x, 4x, 8x, and DSD) and four filter selections: FIR1 (steep roll-off), FIR2 (slow roll-off), and apodizing variants, SDLY1 (short delay/steep roll-off) and SDLY2 (slow roll-off). Out of the box, the default deactivates these settings and each must be applied individually for respective digital sources: disc, USB, and so on. AT discussed these in copious detail and his conclusions (which I urge readers to reference) were borne out by my own findings. Be prepared to spend an afternoon or two experimenting but the results are more than worth the effort. Remember there are no right or wrong answers here, and it only has to be done once as the settings are instantly saved in the K-03X software. In the end, my listening preferences resulted in up-sampling settings of 2x or 4x and apodizing set to SDLY1. In unfiltered, non-oversampled default mode, the sound was flat, thin, dry, and rhythmically uninvolving, but with preferred settings I observed greater focus, presence, dimension, and ambient energy.
For DSD file playback over USB including double DSD, I downloaded the latest free Esoteric HR Audio player software. This is basic, no-nonsense player software (no remote app for a smart device is currently available) to get up and running but many users will likely opt for advanced player software from the likes of Audirvana as they become acquainted with potential of the medium.