Toslink Digital Audio & The Lifatec Silflex Optical Cable

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Lifatec Silflex glass optical cable

The transmission of digital audio signals has evolved and improved over the years, resulting in several standard formats for both consumers and professionals. When Sony and Phillips were creating the Red Book CD standard they also included an option for digital audio to be transported between components. While the S/PDIF (Sony Philips Digital Interface) standard was created using coaxial cables (electrical voltages over copper) with RCA connectors, Toshiba proposed a novel solution. Optical light emitted from a red LED was used to create  binary pulses that distinguished digital 1’s and 0’s.

Toslink, or more accurately EIAJ optical, is the standard for using collimated light in the transmission of digital audio. Optical fibers are used as circular dielectric wave-guides that transport optical energy and information.

Early forms of this technology suffered from jitter (phase noise from inaccurate clocking) and data errors or drop outs from bandwidth-limited optical cables. Using digital audio chips with improved clocking and digital inputs aimed at reducing jitter is a good start, but to ensure those binary pulses of light reach your downstream component (i.e. DAC) without error requires a cable capable of delivering the full bandwidth spec of the Toslink standard.

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                                       Lifatec custom machined Toslink connectors

While I use AES digital connections in much of my professional audio work, Toslink optical interfaces are often the only available digital input/output for many consumer devices. Apple TV, Playstation, Roku, and most flat screen TV’s only provide optical outputs. With mixed results from Toslink cables made of plastic, I began researching Toslink cables made from glass fiber strands.

After some digging, I stumbled upon LiFaTeC® GmbH, and their North American partner Lifatec USA. The American firm specializes in using optical borosilicate fibers in lighting and sensing products for the medical market, and since 2000 Lifatec USA has been manufacturing glass Toslink cables in Elbridge New York – named the Silflex glass cables.

To achieve a bandwidth beyond the Toslink spec, Lifatec uses 470 glass fiber optic strands in the Silflex glass cables. These glass fibers are custom built specifically for audio data applications. Keeping these strands in place is a smooth outer jacket that encases the fine fibers called Optisilk. Before terminating the glass strands, the ends are bonded together and polished to a 1 micron optical finish (including the connector ferrule). Then, a custom machined Toslink connector that is both robust and lightweight ensures a tight connection without light leakage.

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Lifatec glass optical cable with mini Toslink connectors on one end (Apple Laptops)

For my testing, a 10 ft Lifatec Silflex cable was used to link digital audio sources with digital to analog converters. I used my Playstation and a Blu-Ray player’s optical output to send digital audio data to several DACs for testing. All of my DACs quickly locked to the incoming signals without a hiccup. Sonically, the sound of the Silflex glass cable was clear and transparent, imparting no sound of it’s own. The most important difference I found, when compared to other optical cables, was the tight fitting connector in the Lifatec cables. I used one optical cable where the manufacturer thought it was a good idea to machine a Toslink connector with an unnecessary amount of bulk, which added weight. This inferior connector (from a popular audiophile manufacturer) would easily fall out of the female Toslink socket, not so with the Lifatec cable.

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The custom machined Lifatec Toslink connector is both lightweight and tight fitting

After spending some time with these cables in my system, it became clear that the Lifatec cable was a well engineered product for optical audio transmission. Fine borosilicate fibers and smooth outer sleeving allow the cable to flex and fit around components with ease. The finely polished ends ensure a strong optical signal, and the robust/lightweight connectors prevent any light leakage. It is rare to find such a well thought out cable with quality in every part of the build. It’s even less common to find these high-end custom designs at real world prices. Without hesitation, it is my pleasure to recommend the Lifatec Silflex cable for all your optical audio connections.

Happy Listening!

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Channel Islands E•200S Stereo Amplifier

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Channel Islands Audio E-200S Front Panel

The last time I tried out some of Dusty Vawter’s amps I was toting two hefty monoblock amplifiers down the Pacific Coast Hwy. On this journey, my payload was significantly lighter. The E-200S stereo amplifier box fit snugly into the back of my Subaru, and once home, this small unassuming amplifier took center stage powering my 2 way speakers- Green Mountain Audio Eos HX.

Getting it out of the box, was a snap (14.0”W x 2.75”H x 10.0”D). The size and weight of this amplifier made setup and handling a breeze. While the front panel grants access to an on/off button with blue LED surround, the host of usual connections can be found on the amp’s business end. Whether you choose RCA or XLR inputs, the custom differential input stage is used. Then an updated UcD Class D stage drives the output. Speaker binding posts are insulated and accept spades or bananas, and a trigger input is also made available. Power cable plugged in, and we are off.

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200 watts per channel @ 8 ohms/ 400 watts per channel @ 4 ohms

For music, I used a Macbook Pro running iTunes/Pure Music 3. The DAC was my Crane Song Avocet, and the Antelope Audio Zodiac Platinum. With everything connected via balanced cables and several hours of warm up (this amp had already been burned-in) I was ready to start listening to some of my favorite tracks.

I cued up some acoustic music by Kings of ConvenienceThis Norwegian duo offers a great starting point to evaluate the naturalness of the male voice. Listening to “Rule My World” from “Declaration of Dependence” gave me some lovely acoustic guitars with harmonizing male vocals.

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View from above, notice the small footprint

The two part acoustic picking of “Declaration of Dependence” maintained all the midrange richness while allowing the male vocals to almost float above the gentle picking style. The clarity of guitars and male voices were presented in an un-hyped and natural way.

Moving onto more complex works, I began listening to Herbie Hancock’s “Steppin’ in It.” This groove laden funk from Mr. Hancock’s “Man-Child” album features rich synth leads, a tight bass lines from Paul Jackson, and a stellar harmonica solo by Stevie Wonder. Allowing all that musical articulation to shine through requires some control over loudspeaker movement. The E200-S gripped My Eos HX and allowed each and every bass note to come through with precision and depth. While everyone in the band holds down the groove, Herbie takes the Rhodes for a stroll… and before you know it Stevie Wonder is syncopating a harmonica unlike I’ve ever heard. With each breath, a new note even funkier than the last is pumped out. All these counter rhythms and complex instruments can be demanding on an audio amplifier, and the CI Audio E-200S never slowed down. In fact, the intricate stereo soundstage was expansive. To top it off, the tonality of instruments (even the squeaky high harmonica) never sounded dull or harsh.

To verify the neutrality, I relied on several orchestral and vocal ensemble recordings I made for NPR, all at the same performance hall. While less capable amplifiers have shown some distortions or break-up, I’m happy to report that the CI Audio amp had none of those shortcomings. Localizing mic placement, hall width/depth, and reverb decay were all amplified without coloration. This provided a sonic portal to the original recorded events, an immersive experience indeed.

Spending time with the E-200S was revealing in so many ways. From black quiet backgrounds to fully erupting orchestral performances, this little beast was in control. Most of all, this CI Audio amplifier proves that green design and audiophile sound need not be mutually exclusive.

Happy Listening

Records in Heavy Rotation…Organized!

File folder organizer used as vinyl LP display/holder

This clear file organizer found a second home with my record collection. My file holder turned record organizer is a stylish and inexpensive way to show off your favorite albums. It has 6 divisions, and you can fit between 2 and 4 LPs in each compartment. A clear choice for displaying your current record rotation. you can find this product at places like this.