[T]his review was birthed as a result of an online discussion regarding digital sound quality in which both Steve Nugent of Empirical Audio and I participated. I had mentioned the Eastern Electric Minimax DAC, which is said to eliminate jitter through its use of stacked ESS Sabre 32 bit Reference chips in each channel. (See the original Audio Blast, Opamp Rolling and DAC Plus articles. -Pub.) Steve asserted that the DAC does not eliminate enough jitter, a comment which prompted dismay on my part. I contacted him for explanation, and the discussion led to this review! I will be weighing in on what happens when Empirical Audio’s Synchro-Mesh is used with a DAC which is said to eliminate jitter.
I had previously discussed the operations of the ESS chips with Calto Wong from ESS Technologies and recall his indicating that the 8-channel DAC technology from ESS eliminates jitter. I returned to the white paper for the Reference 32 bit DAC chips, “Technical Details of the Sabre Audio DAC” by Martin Mallinson and Dustin Forman of the ESS Technology Technical Staff, and re-read this segment:
Care is taken in the digital signal processing (DSP) to ensure that jitter rejection is essentially perfect: a patented technique is used to re-create the audio data in a crystal-controlled low phase-noise clock domain completely isolated from the clock domain of the transport medium and so not at all related to the clock domain in which the data was sampled. This latter feature ensures that there is zero jitter transfer from the various interface clocks to the digital data and that the digital clock of the DAC itself can be optimized for noise and power consumption. Finally, operation of the DSP in the transport medium clock domain (the “Fs” domain in which data is delivered to our DAC) is done in a “gated clock” mode – a form of serial/parallel processing that prevents any inter-modulation of operating current between the DAC clock and the data transport clock that could cause harmonically related noise on the system power supplies.
I am not an electrical engineer, so who am I supposed to believe? The man who says the data stream reaching the DAC needs to be purged of jitter, or the man who says jitter in the data stream is purged by the DAC? It’s not uncommon for an audiophile to encounter seemingly conflicting information from different sources in regard to a method or product. In this case, we have two companies which say they effectively eliminate jitter such that the sound is radically improved. Despite whatever conflicts may arise between claims of products’ performance, my job is to assess the practical benefit of a product under review with an eye toward its potential efficacy for the audiophile.
One thing becomes obvious quickly; there is no consensus of opinion when it comes to digital playback, even among experts in the field. I intend on reporting what I found in regard to the functionality and benefits of the Synchro-Mesh. I have been using the Minimax DAC in reviewing for some time now, so whatever digital product comes through the door is going to be used in conjunction with it. I have other DACs available which will also be considered in this article.
What happens when a jitter-free source meets a jitter-free DAC? Is there an audible improvement? Do they cancel each other like matter and antimatter? I’m not sure how the average audiophile is supposed to assess each of these manufacturer’s claims. However, the test of practicability, the daily usage of a product, still applies. This review will ultimately determine the efficacy of the Synchro-Mesh with and without supposed jitter-free DACs.
Unimaginative, but effective
Operationally, the Syncro-Mesh is a 16- or 24 bit reclocker which is available from Empirical Audio at up to 192 kHz output. The heart of it, the Hynes Regulator licensed from Paul Hynes in Scotland, is a voltage regulator which according to Steve, “…delivers fast responding power with ultra-low noise to the oscillators and other circuitry, enabling the jitter to stay very low.” Physically, it is unobtrusive, with no POWER button; it works when you plug it in. It does have a switch to toggle between 16/24 bit operation upon power up. Toslink (optical), S/PDIF (coaxial) and BNC inputs are provided singly making the Syncro-Mesh a dedicated device.
Only an engineer names his audiophile product the “Synchro-Mesh.” It sounds more like a hybrid product from Casio electronics and Columbia outerwear, perhaps a jacket with an LED screen woven into it. One might lay out the jacket on a table and use it for a screen, but just imagine the difficulties in trying to make it waterproof! Alternatively, Synchro-Mesh could be a remix of Sting’s hit “Synchronicity”, which had the intellectual depth of quality comparable to the build quality of Ikea furniture. Thankfully, the unimaginatively named Syncro-Mesh is neither a trite thought nor a product DOA, but rather a useful “bridge” component designed to mesh two devices with disparate digital time domains such that they meld, creating a superior digital source. (Synchromesh is a term pertaining to transmissions; all of Steve’s product names relate to cars and/or racing. -Exec. Ed.)
Persons who live out in the rural parts of the United States know what a “correction line” is, an adjustment to seemingly parallel roads to account for the curvature of the earth. SuperGlossary.com imparts this wisdom defining Correction Lines:
“Provisions in the rectangular survey (government survey) system made to compensate for the curvature of the earth’s [sic] surface. Every fourth township line (at 24-mile intervals) is used as a correction line on which the intervals between the north and south range lines are measured and corrected to a full six miles. Range lines are only parallel in theory. Due to the curvature of the earth, range lines gradually approach each other. If they are extended northward, they eventually meet at the North Pole. The fact that the earth is not flat, combined with the crude instruments used in early days, means that few townships are exactly six-mile squares or contain exactly 36 square miles.”
Fascinating, I know. However, the principle is critical; if one does not make adjustments to rough measurements they will become increasingly inaccurate when extrapolated, like roads which are not quite parallel converging. Similarly, a seemingly flawless digital signal jockeyed between a digital source and a DAC may not be time aligned, or synchronous. It may contain “jitter”, a mistiming artifact that causes digital music to sound stilted compared to analogue.
Itty bitty bits
The temptation when discussing such things as reclockers and Picosecond variances is to say, “BWAAAA! THAT little bit can’t mean so much audibly!” Truly, we’re talking miniscule variances that most music enthusiasts would roll their eyes at when a suggestion of improvement through re-timing is brought up. CD players and streaming audio work perfectly fine. Or, do they? We live in a nano-world, where the most Lilliputian nick of material or nick of time is critical. Otherwise, why would we use digital timers for races, or robotic systems for surgery, IV drips in hospitals, or electronic trading programs in churning the Market, err… I mean Investing? The reclocking credo is that a bit is not a bit; it’s a bit either on time or not. If it’s not on time it sounds a bit worse!
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