Transports, Interfaces & Clocks

The ACCUSTIC ARTS® DRIVE I is a CD transport made by ACCUSTIC ARTS® and handmade in Germany. It uses a vibration-decoupled, tray-loading CD drive mechanism designed for audio applications, a damped aluminium-ABS drawer with two metal bearings, two separate power supplies for laser control, digital signal processing and display control, and two 25 VA toroidal-core transformers. The unit has a resonance-minimising metal housing, a finely brushed aluminium front panel, a massive chromed-brass tray cover, coaxial S/P-DIF and TOSLINK outputs, supports CD, CD-R and CD-RW formats, and measures 130 × 482 × 380 mm, weighing approximately 12 kg.

The ACCUSTIC ARTS® DRIVE II is a top-loader CD transport manufactured by ACCUSTIC ARTS®, designed to play CDs, CD-Rs, and CD-RWs. It uses a CD-Pro8 mechanism with a three-beam laser, die-cast metal chassis, mechanically decoupled subchassis construction, massive aluminium housing, separate power supplies, and two magnetically shielded toroidal transformers. Digital outputs include coaxial S/P-DIF and TOSLINK; dimensions are 165 × 482 × 375 mm and weight is 21.5 kg.

The ACCUSTIC ARTS® DRIVE IV is a top-loader CD transport made by ACCUSTIC ARTS®, designed to play CDs, CD-Rs, and CD-RWs. It uses a CD-Pro8 mechanism with a three-beam laser, die-cast metal chassis, mechanically decoupled subchassis construction, a massive aluminium housing, an acoustically damped slide cover, and a magnetic puck; its power supply includes two magnetically shielded toroidal transformers and separate supplies for the drive components and digital output stage. Digital outputs comprise coaxial S/P-DIF and TOSLINK S/P-DIF; the unit measures 165 × 482 × 375 mm, weighs approximately 22.5 kg, and is specified for WAV CD data.

The Antelope Audio 10MX is the premier member of the company's Isochrone clocking line, combining a Swiss-made rubidium atomic oscillator with Antelope's 4th-generation 64-bit Acoustically Focused Clocking (AFC) DSP to deliver an ultra-stable 10 MHz reference and master clocking up to 768 kHz. Note: the task referenced this product as the "10M," but Antelope's current flagship rubidium clock is the 10MX, the successor model documented on Antelope's site and in its official owner's manual.

The Isochrone OCX HD is Antelope Audio's flagship standalone master clock generator, built around a 4th-generation 64-bit Acoustically Focused Clocking (AFC) engine and an oven-controlled crystal oscillator, with an optional input for syncing to Antelope's 10MX rubidium atomic clock for even greater long-term stability. Designed for mastering, recording, and post-production environments, it distributes ultra-low-jitter word clock, AES/EBU, and S/PDIF timing references to an entire digital audio chain at sample rates up to 768 kHz.

The LinQ is Aqua's modular network transport/interface, built around a fully isolated, upgradeable multi-board platform with up to four plug-in renderer modules (Roon-ready HQPlayer Core+NAA, UPnP/DLNA, Squeezelite, Tidal Connect, Qobuz Connect) and a proprietary internally-developed, galvanically isolated LAN switch stage. It deliberately omits a USB output, instead delivering its cleanest signal over Aqua's proprietary AQlink I2S connection alongside conventional S/PDIF, AES/EBU, and dual-AES outputs.

The Ayre QA-9 Pro is a professional analog-to-digital converter for recording, mastering, archiving, and product development. It uses a discrete, fully balanced, zero-feedback analog circuit with variable gain input control, Equilock circuitry, and separate left/right recording-level meters; digital conversion is built around the Arda AT1201. Outputs support up to 24-bit/192 kHz USB Audio and AES/EBU, with an optional word-clock/DSD output board providing word-clock rates from 44.1 to 192 kHz and SDIF-2/SDIF-3 DSD output.

The MA2 is Cybershaft's mid-tier standalone 10 MHz master clock, sold with a choice of hand-selected, long-term-calibrated OCXO grades (OP17 through OP19) to trade price against phase-noise performance. Its dual-chassis, vibration- and magnetically-shielded construction targets audiophiles wanting a genuine step up from entry-level clocks without moving to Cybershaft's flagship Palladium line.

The dCS Vivaldi Master Clock is a Class 1, temperature-compensated master clock built around dual VCXO (voltage-controlled crystal oscillators) with microcontroller-enhanced temperature correction, designed as the timing reference for dCS's flagship four-box Vivaldi digital playback system. It provides two independently configurable banks of four buffered word-clock outputs and can itself be slaved to an external reference such as an atomic clock or GPS source via its 75Ω BNC reference input.

Empirical Audio is a small direct-order US boutique (run by Steve Nugent) that has developed proprietary digital-audio techniques for over two decades; the Synchro-Mesh is sold only via direct email/PayPal-invoice order rather than through retail distribution, a hallmark small-batch business model (Empirical Audio). It re-clocks or logically replaces a source's clock using asynchronous sample-rate conversion and a Crystek oscillator, and has been reviewed by 6moons, Dagogo, AudioScienceReview, and Ultra High-End Review, with 6moons noting an "unprecedented" measured jitter figure of about 7 picoseconds (6moons; Empirical Audio).

The Esoteric G-02X is a master clock generator built around a custom high-precision oven-controlled crystal oscillator (OCXO), designed to supply reference timing to up to eight digital audio devices simultaneously. It features an "Adaptive Zero Ground" circuit to suppress ground-voltage-induced random jitter and offers independently configurable output frequencies across its four general-purpose clock terminals plus four dedicated 10 MHz sine-wave outputs. Esoteric's official specifications page now lists the G-02X as discontinued.

The CC1v2 is Grimm Audio's flagship master clock and AES/EBU reclocker, built around a radically redesigned discrete crystal oscillator circuit and a deliberately slow, ultra-stable phase-locked loop. It offers 16 word-clock outputs across two independently configurable groups plus a reclocked AES3 output, making it a reference-grade hub for synchronizing multi-device digital playback and mastering systems.

The Grimm Audio CC2 is a compact, ultra-low-jitter master word clock built around a discrete, largely hand-built oscillator and power-supply design, intended as a reference timing source for both professional studios and audiophile digital front ends. It operates only as a master (no slave mode), providing two simultaneously controlled word-clock BNC outputs at 44.1kHz or 48kHz base rates with switchable multiplication factors of 1, 2, or 4, covering sample rates up to 192kHz.

The C16 is Gustard's dedicated 10 MHz OCXO master clock generator, designed to feed a high-precision external reference into DACs, streamers, and other clock-input-equipped digital gear at a fraction of the price of most standalone audiophile clocks. It uses a custom SC-cut oven-controlled crystal oscillator and offers six BNC outputs split between direct and isolated output banks.

The Ideon Audio Absolute Time is a USB/SPDIF reclocking master clock rather than a conventional word-clock generator: it takes in USB or coaxial S/PDIF signal, reclocks it using multiple proprietary ultra-low-jitter "femto clocks," and outputs a cleaned-up, re-driven signal (plus a 12.8MHz master clock reference on BNC) to the downstream DAC. Its USB output includes a high-current 2.5A/5V rail intended to power connected DACs' USB input stages cleanly.

The NET3 is Innuos's enthusiast-level audiophile network switch, built as the natural successor to the discontinued PhoenixNET and designed as the network partner for the company's STREAM3 streamer. It uses a 3ppb OCXO clock on a dedicated power rail, an exclusive "WaveNET" board with SFP fibre isolation, and a NAZARÉ-derived linear power supply to remove electrical noise from the network path feeding a streaming DAC or server.

JCAT is a small Polish audio-computing specialist (associated with Marcin Ostapowicz and the JPlay software project) that hand-upgrades its own USB Card XE/EVO interfaces at its Poland factory rather than selling through wide retail channels (HiFi Knights; JCAT). The Master OCXO Clock Module is JCAT's first in-house, ultra-low-noise oven-controlled crystal oscillator clock generator, developed with a radio-physics specialist and offered only as a factory-installed retrofit for existing JCAT cards, reviewed in depth by HiFi Knights and Alpha Audio (HiFi Knights; Alpha Audio).

The OCK-2S is LHY Audio's high-precision reference master clock generator, built around a selected SC-cut OCXO and offering six isolated 10 MHz outputs (three sine-wave, three square-wave) to synchronize DACs, transports, and USB bridges with 50/75Ω clock inputs. LHY Audio is a sister brand of CD-transport maker Jay's Audio, and the OCK-2S sits above the brand's earlier OCK-2 model reviewed by 6moons.

Métronome Technologie is a small French manufacturer based in Montans that designs and builds its CD transports in-house rather than through mass-market contract production; the DST is the latest slot-in CD transport in its "Digital Sharing" range, built to partner with the brand's DSC mini and DSS 2 components (Métronome). It has been reviewed by enthusiast and trade outlets including 6moons and EnjoyTheMusic, and the brand maintains a limited dealer network typical of a boutique high-end operation (EnjoyTheMusic).

The MC-3+ USB is Mutec's audiophile master clock, digital audio re-clocker, and asynchronous USB-to-AES/S-PDIF interface in a single 9.5-inch rack-space chassis. It uses Mutec's proprietary 1G-Clock and REVIVE re-clocking technology to bit-transparently clean up jitter from computer and streaming sources, and can lock to external references including the Mutec REF10, rubidium, cesium, and GPS clocks for further precision.

The REF10 Nano is Mutec's compact, entry-level standalone 10 MHz reference master clock, distilling the brand's OCXO clocking technology into a smaller chassis at a lower price point than the flagship REF10 and REF10 SE120. It provides four independently selectable BNC reference outputs for synchronizing DACs, streamers, and other digital-audio components.

The Mutec REF10 SE120 is an enhanced version of Mutec's REF10 that uses a more elaborately manufactured, hand-selected oven-controlled crystal oscillator (OCXO) made in Germany, delivering what the manufacturer describes as among the lowest phase-noise and jitter figures in its class. It outputs eight simultaneous, galvanically isolated, individually switchable 10 MHz reference clock signals across both 50Ω and 75Ω BNC connectors.

The Nagra VI Film is an 8-channel digital audio recorder made by Nagra for film and documentary production. It provides four microphone preamplifiers, two line inputs shared with AES-3 inputs, 24-bit recording at sampling rates from 32 kHz to 192 kHz, SMPTE/EBU time code with chase synchronization, and BWF files with iXML metadata. Recording uses an internal 120 GB 2.5-inch hard disk and removable Compact Flash media; the Anniversary Edition is available with a machined aluminum front panel.

The Pro-Ject CD Box RS2 T is a top-loading CD transport made by Pro-Ject Audio Systems for playing Red Book CD-DA discs. It uses a StreamUnlimited CD-Pro 8 mechanism with a Blue Tiger CD-84 servo board, a magnetic aluminium-alloy clamp, and a suspension system incorporating a rigid carbon-fibre chassis, carbon-fibre tubes, springs, silicon dampers, and screws. Digital outputs include AES/EBU over XLR, optical and coaxial S/PDIF, and I²S plus Masterclock via HDMI; the unit has no built-in DAC or preamp and is housed in a precision-machined aluminium chassis available in silver or black.