Equipment Review

Splitting time: Esoteric G-02X Master Clock takes accuracy to new levels…

By Jack Lawson · 12th Apr 2017
The G-02X featuring those distinctive, sleek Esoteric lines.

Having pioneered digital processing over three decades Esoteric’s 30th anniversary clocks are a technical triumph and a musical revelation. We tested the entry level G-02X – not cheap at £5,500 so what does it do?

Here is a clock that is extremely accurate but it won’t tell you the time. What it will do is express these little words or packages of digital bits from all and many sources instead of jumbled up, in order, and on time. As a collector of music on super audio and 16-bit CDs this is my main source. Silver discs. But when I jump to network-based music players, the G-02X will be even more justified.

Eager to confirm whether or not I was crazy to have ordered such an unusual luxury as a master clock – especially when I already owned a previous model – after weeks of waiting, I was in a hurry to try it out.

A perfect complement to the Esoteric transports and DACs.

I need not have been nervous. Despite its extreme sophistication I set it up in two minutes, without reading the manual. (1) I connected paired outputs A1 and A2 to transport and DAC; (2) I switched on and saw that warm-up was taking place; (3) toggling the options for output A, I selected the familiar 44.1 signal. Ready to go: the transport and DAC LEDs locked on to indicate external “Word”.

This came as a great relief because the menu allows for universal and future-proof options and flexibility. In itself simplicity is the sign of clear thinking and consideration to real world and real music lovers.

Esoteric’s attention to detail is impressive. I recall the A-03 amplifier which they launched knowing that the EU was about to launch energy saving regulations against the audiophiles’ essential stand-by techniques. Their solution was elegant. And in the G-02X you can, via the menu, be law-abiding and eco-friendly by opting out of the pre-heat function.

Esoteric define a clock as a pulse signal used as a reference for all digital circuits. Every digital components has one, but they claim “the G-02X can supply clock signals with a significantly higher degree of purity and stability … and thereby significantly improve the sound quality.”

Let’s consider what the G-02X does technically and musically.

It took a few years before engineers appreciated jitter as a main reason between the theoretical triumph of 16-bit “Red Book” CD and the disappointment of early listeners. For many years clocks have become accurate, so surely that is problem solved? Not so; Esoteric engineers have penetrated the nano dimensions of time and space to develop a core of all-new techniques. These derive from the cost-no-object development of the flagship Grandioso products. Commercial break: phone us for best price. They are heart-breakingly exquisite!! Back to components that I can almost afford.

The heart of the G-02X is a device you can see on their website. OCXO is the acronym for Oven Controlled Crystal Oscillator. Surpassing accuracy the aim goes further; it includes low noise and high phase accuracy of the pulse signal.

And it goes even further.

A series of dedicated power supplies and smoothing capacitors and diodes are implemented for fast digital processing.

Esoteric found sonic improvements from buffered amplifiers for each output.

They also employ an adaptive zero-ground mode actively driving the ground to zero volts which they found to improve the signal musically; you can select normal or adaptive to judge for yourself.

This level of options, features and discrete circuits affords great user control, flexibility and future-proof of the device. Two pairs of clock outputs are co-ordinated (for my transport and DAC, for example) or individually programmed for a choice of frequencies from 44.1 and 48 kHz upwards. Four more outputs provide 10MHz sine wave outputs.

While overwhelmingly impressive the question of the music is now left to this point. I see many big names owned by corporates inventing technology for marketing purposes. But Esoteric embody the finest Japanese ethic of honesty, hard work, and a passion for music.

Accepting this, the G-02X may still surprise you. Their website discusses musical improvement, but what does this mean?

Once the pre-heat kicked in from its very first use, cold out of the box, I had retrieved two familiar discs: first, a 16-bit PCM issue of Jazz at the Pawnshop and later a DSD classical remaster. The jazz recording opens with the ambience of the club but instead of indistinct murmurs, you are there! And when the drums and sax enter, well, the music is so vivid and present that you just have to smile. Whether it is relief at money well spent; or admiration for the boys in Tokyo; or just sheer exhilaration that maybe our crazy, costly hobby is not so pointless, I do not know but, Eureka!! When this happens you let the music run; you do not want to switch off but within seconds the success of Esoteric’s clock technology is all too apparent.

Next disc tried was one of Esoteric’s SACD analogue remasters, the first of four recordings Herbert von Karajan made (in 1960) of Also Sprach Zarathustra. The impressive opening became the theme of Kubrick’s SF movie, 2001 - A Space Odyssey. Featuring the Vienna Philharmonic, the performance unfolds with inner tension and outer beauty. The pace is glacial evolution before explosive energy is expressed by these brilliant musicians. Now you can hear them interact: the menacing bass lines, all kinds of melodies and the recurring themes emerge as complexity but not confusion!

I have to say that use of Esoteric’s clock both in studio mastering and replaying the disc at home establishes the company as one of a decreasing number of elite – should I say Esoteric? – brands for the serious music lover.

There are, after 30 years, many affordable legacy products made by the company on the used market; and Esoteric offer current, entry point products of distinction and it goes up to their fabulous Grandioso series.

If you are thinking about a network player, check out Esoteric’s N-05. It is extraordinary like everything else this company engraves its name on the chassis. And it will, no doubt, justify further your investment in an external master clock.


It quickly becomes apparent that the new master clock technology is a most satisfying contribution to our hobby. It does not improve the usual parameters, but something more fundamental has been corrected. Pianos, guitars sound more distinctive, more flavour and bite. Their unique signatures come through. The finger work of these pianists and guitarists comes over as if clearer by more space between the notes, better rise and fall transients. I will say that in summary, gone is the smudging!

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