Since the Transient II is a USB-only DAC it spent most of the review period tethered to my MacPro desktop computer. It did not require loading any drivers, and the Mac Sound Control Panel immediately recognized the Transient by the name “CIAudio USB Audio 2.0” and showed support for bit-rates up to 192/24. I used the Transient with iTunes, Amara, Pure Music, Decibel, Audirvana Plus, Audacity, and Audiogate without a single compatibility issue.
How does the Transient II sound? Well, it sure doesn’t come across as a “budget” component. Used as a USB-to-S/PDIF converter the Transient rivaled the more expensive Human Audio Tabla ($995) in S/PDIF when it was running into the April Music Eximus DP-1 DAC/preamp (the DP-1 has two S/PDIF and two analog inputs, so it’s ideal for real-time A/B comparisons). Although the latest Empirical Audio Off-Ramp 5 combined with the new Empirical Audio Short-Block isolation filter did have a slightly larger soundstage and lower noise floor, I had to use my own live recordings to clearly discern the difference—on commercial recordings the two USB converters sounded almost identical.
For optimum performance Channel Islands recommends using the Transient II’s I2S outputs. Fortunately, the Wyrd4Sound DAC II has I2S connections so I could hear the Transient II’s I2S performance for myself. It was easily the best sound I heard from both the Transient II and the Wyred4Sound DAC II. The improvement was principally in dimensionality. Not only did the front-to-back depth increase, all the instruments and voices gained additional solidity and edge definition. It was a lot like going from a very good solid-state power amplifier to a tube amp; the 2-D image morphed into 3-D. I used a PS Audio Perfect Wave 12-1 I2S cable for the connection. I also tried a generic HDMI cable, and while it, too, was superior to the S/PDIF connection, the imaging improvements were far less obvious. When I switched back to the Wryed4Sound’s own built-in USB implementation and compared it with the Transient II’s S/PDIF output, the dimensional presentations from the same USB source were virtually identical.
As a stand-alone USB DAC/Pre the Transient II gets high marks. If you can get by with one pair of single-ended RCA outputs the Transient II can serve as the center of your computer audio system. I was impressed by the Transient II’s lack of electronic edginess. Especially on voices, such as Emma Kirkby’s delicate soprano on the live concert album Time Stands Still [Hyperion], the lack of grain and glare lets the music flow with relative dynamic freedom. Unlike some budget gear, which sounds clean yet sterile, the Transient II’s overall presentation had an ambience and bloom that were natural and relaxed, without the slow, thick sound of some vintage tube gear.
Listening to my own DSD-format live concert recording of the Boulder Philharmonic performing Brahms’ Double Concerto in A minor for violin and cello played back through Audirvana Plus’ real-time DSD-to-PCM converter at 176/24, I was most impressed by the Transient’s ability to preserve all the subtle spatial details that were present in the recording. The violin and cello soloists were so clearly defined in space that when the violinist turned his body, even slightly while playing, it was immediately obvious. The Transient also did an excellent job of retaining all its sonic virtues even on double-forte passages— the sound didn’t get harder or more aggressive during dynamic peaks.
Near the end of the review period Channel Islands sent me its $329 VDC-5 Mk II high-current power supply. While I didn’t detect any improvement or sonic changes in the S/PDIF or I2S streams when I installed the VDC-5 Mk II, I did hear an improvement in the quality of the Transient II’s analog outputs. Dynamic contrast improved with greater image stability and focus. According to Dusty Vawter, whether the VDC-5 Mk II makes a sonic difference will depend on a number of factors, such as the noise generated by your computer’s video card and the noise on the USB connection. With some portable computers running on their battery supply the VDC -5 Mk II will make no sonic improvements. But if you run them plugged into AC, the VDC-5 Mk II will reduce the noise coming from the USB power supply. Given the VDC-5 Mk II’s cost, I would strongly suggest trying it out on your own system since it may not be the most cost-effective upgrade for the Transient II, especially if you are using the Transient II primarily as a USB-to-S/PDIF bridge. If you have an I2S-compliant DAC I would recommend investing in a high-quality HDMI-type cable before springing for the VDC-5 Mk II power-supply upgrade.
MY TRANSIENT RESPONSE
To say I was impressed by the Transient II’s combination of modest price and excellent sonics is something of an understatement. If you are contemplating spending $700 or more for a USB-to-S/PDIF converter, you should consider the Channel Islands Audio Transient II. For a reasonable price it lets you keep up with the current state of USB 2.0-compliant audio, even if your DAC lacks USB capabilities. And while we wait for the next wave of products with USB 3.0 compliance, the Transient II will keep your music flowing beautifully.
LINDEMANN USB-DAC 24/192 CONVERTER AND DAC ($1100)
The second DAC in this survey comes from Lindeman. Although in business for more than twenty years, Lindemann is a relative newcomer to the United States. Now distributed by One World Audio, this German company, formed by Norbert Lindemann, opened its doors in 1992. In 1999 Lindemann introduced the first upsampling CD player, and in 2002 the first German- manufactured SACD player. Releasing leading-edge digital products is nothing new for Lindemann, and its latest USB DAC is no exception.
Understatement in physical design is a hallmark of Lindeman products. The Lindeman USB DAC is a small 11⁄2" by 43⁄4" by 5" silver-tone box with a single circular push-button on the front. The rear panel has inputs for USB, TosLink, and S/PDIF, one pair of RCA single-ended outputs, and a power-supply connection. That’s it. The only user adjustment is the source-selector button on the front. And while the Lindemann USB-DAC 24/192 may appear, at least from the outside, to be a modest entry-level offering, inside it’s packed with Lindemann’s current thinking on state-of-the-art digital technology. The USB interface is based on the XMOS DSP chip, and offers asynchronous “bit-transparent” resolution up to 192/24. The digital interface controller is the Wolfson WM8805, and the DAC chipset is the Wolfson WM8742. According to Lindemann’s published specifications, the USB DAC 24/192’s internal master clock produces less than 2.5 picoseconds of timing errors. The USB 24/192 also uses a “minimum phase” digital filter with an “apodizing” filter to reduce phase, timing, and group-delay issues.
For jitter reduction the 24/192 features an active jitter- reduction scheme that employs a digital PLL (phase locked loop) and memory buffering of the digital stream. According to Lindemann, “The remaining jitter of the signal (not the clock!) is below 50 picoseconds.”
Although the analog outputs are single-ended RCA, the Lindemann DAC employs a fully balanced analog output stage with bandwidth that extends up to 200MHz. According to Lindemann, “As a result of the silicon-germanium technology used for the wafer, the module’s supply voltage is limited to 5V. The result of this is an optimal output voltage of 1.4V RMS for 0dBFS. Consequently, the USB-DAC 24/192 is quieter than competitors using standard operational amplifiers.” As you would expect from a USB 2.0-compliant device, no additional drivers or plug-ins are needed for Mac use. For Windows machines Lindemann offers a certified driver and installation instructions.