This review page is supported in part by the sponsors whose ad banners are displayed below

Paul Candy
Financial interests: click here
Digital source: CEC TL51X transport, SOtM sMS-1000 network server [in for review], SOtM sDP-1000 & sMS-1000 power supply [on loan], Asus laptop, Win 8, J. River Media Center 18/19, JPlay 5.1, John Kenny JKSPDIF Mk3 USB-SPDIF interface, Audiomat Tempo 2.6 DAC
Analog source: Well-Tempered Lab Amadeus with DPS power supply, Pro-Ject Tube Box SE phono stage, Ortofon Rondo Blue MC cartridge
Amps: Audiomat Opéra Référence integrated
Speakers: Jean-Marie Reynaud Evolution 3, REL Q108 Mk II subwoofers (2)
Cables: MIT Magnum M1.3 cabling, Transparent, Nordost & Cardas USB cables, Sablon Audio Panatela cabling [in for review]
Power cords: MIT Magnum AC1, Wireworld Aurora 5² & Silver Electra 5², Sablon Audio Robusto, Gran Corona & Petite Corona [in for review]
Stands: Grand Prix Audio Monaco four-tier rack on APEX footers with silicon nitride bearings, IKEA, Skylan damping boards, Gingko Cloud 10
Powerline conditioning: BPT Pure Power Center with Wattgate, Bybee Quantum Purifier and ERS cloth options, Blue Circle BC86 MK5, Blue Circle 6X & 12X AC Filters
Sundry accessories: Acoustic Revive RR-77, Audio Magic/Quantum Physics Noise Disruptors, Caig Pro Gold, Echo Busters acoustic room treatments, Isoclean fuses, HiFi Tuning Disc Demagnetizer, Nitty Gritty record cleaning machine, Soundcare Superspikes (on speakers), dedicated AC line with CruzeFIRST Audio Maestro outlets
Room size: 11x18x8', long wall setup, suspended hardwood floors with large area sisal rug, walls are standard drywall over Fiberglas insulation
Review component retail: $999/.8m, $1.399/1.6m, $1.999/3.8m

If you are at all interested in file-based music playback, chances are you’ll require a USB cable somewhere in the chain, most likely between computer/server and DAC. Yes, that same cheap wire that connects pretty much every peripheral device to your computer can have a significant impact on music playback not unlike interconnects and speaker cables. As much as it pains my inner cynic, I have observed significant improvements even with moderately priced aftermarket USB cables over their generic brethren for reasons I do not fully comprehend. What gives? After all, aren’t we just sending packets of data from one device to another? As long as the data is intact, what could possible affect sound quality? It turns out it’s far more complicated than that. There are measurements to prove it too. In the July 2013 issue of Hi-Fi News & Record Review, several USB cables were tested and reviewed. The cables with faster rise times and better eye patterns were generally preferred over cables with lesser test results. If I understand editor Paul Miller’s explanation correctly, the measurements clearly illustrated differences in the shape of the waveform arriving at the input of a USB DAC via their eye pattern. Poor eye pattern indicated issues in the time domain i.e. jitter. Obviously timing is everything when it comes to music playback. All of this brings me to the subject of today’s review, Light Harmonic’s Lightspeed USB cable which retails for a not inconsiderable $999.

While designing Light Harmonic’s highly regarded Da Vinci DAC, founder & president, Larry Ho observed that their USB cable was often the weakest link in many computer-based playback systems. By isolating USB power, reclocking the signal,and buffering it with a patent-pending three-layer buffer in his Da Vinci DAC, Larry minimized the cable's effect. Still, bit perfection and original precise timing of the digital signal was often lost in the USB cable. After testing dozens of aftermarket USB cables Larry found that many couldn’t even achieve the 480Mps bandwidth required by the USB 2.0 standard. Often signal integrity was damaged by noise on the power leg of the cable.

As a result of this research the Lightspeed USB cable was born. It uses a topology which Light Harmonic calls
ultra-high speed differential pair (USDP) which physically separates the signal leg from the 5V power leg to prevent source-generated noise from disturbing the digital signal. Light Harmonic claims a whopping 10Gbit/s bandwidth which is roughly twenty times that of the USB 2.0 standard of 480Mbit/s.

The Lightspeed is available in a standard configuration-both legs terminated in a single connection at both ends-as well as in split configuration which has one USB-B connector and two USB-A connectors, one for signal and one for power. The split configuration is aimed primarily at self-powered DACs such the Da Vinci. I requested the standard configuration with a shared connection at both ends. Specifications are as follows: