Headphones are hot these days. And, like much of the rest of the high end, headphone prices have been smashing through one upper price threshold after another. It was not very long ago that a $1,000 pair of headphones was exceedingly rare, the purview of Stax and a scant few other esoteric models. These days, when shopping at the upper end of the spectrum anyway, a grand is more like the starting point, with plenty of models in the fifteen hundred and up range.
Computer audio too is gaining momentum, with plenty of audiophiles (myself included) ditching their CD players for computer based music server systems. This has led to the birth of a new product category, the USB DAC – simply a digital to analog converter that will accept a digital input via USB connection from a computer. Into this fray wades the CEntrance DACport, a very clever and timely bridge between your computer and your headphones.
The DACport, in function and use anyway, is delightfully simple. Plug one end of the supplied USB cable into the DACport and the other into your Windows, Mac or Linux PC, and presto you’ve got remarkably high quality, 24/96 capable sound coming out the ¼” connection at the other end (which can service headphones, of course, but also serve as a line level input into powered speakers or even a preamp or integrated amp – just turn the volume control up all the way). The DACport is truly “Plug and Play” – there are no drivers, no installation discs, no updates, no power cables (it’s powered directly off the USB bus of the computer) and, most importantly, no hassle – and that’s saying something when it comes to computers. The only thing you may have to do is select it as your output choice in your computer’s audio options. When the DACport is selected your computer’s internal volume control is disabled (the computer is now a digital source or transport feeding line level digital audio to the DACport) and you control volume directly with the analog potentiometer on the top of the DACport. You’re up and running in a couple of minutes. Refreshingly simple.
What’s happening inside the DACport is a little more complicated. If you Google “USB DAC” it won’t take you more than a couple of mouse clicks to wade into the debate about how best to implement digital audio over USB. Reading all this will quickly give you the impression that, in a nutshell, there are two main ways to go: asynchronous and adaptive, the details of which I’m not going to bore you with here, sufficed to say asynchronous puts the DAC in control of the master clock and adaptive puts the computer in control of the master clock. Asynchronous acolytes will tell you it’s the only way to fly, but CEntrance begs to differ and has come up with their own, custom adaptive implementation. They’ve developed something called “AdaptiWave”, which not only works extraordinarily well based on the quality of sound that comes out of this thing, but has been licensed by no less than the likes of Benchmark Media, Bel Canto, and Empirical Audio among other manufacturers.
Instead of using an off the shelf USB audio chip (usually the same 16-bit / 44.1kHz Texas Instruments chip that appears in a myriad of cheap sound cards and the like) CEntrance developed a custom chipset with a separate USB controller optimized with their “AdaptiWave” code to move enough data for 24/96 performance through the “thin USB 1.1 pipe, where very little bandwidth is available.” As their website proclaims, “CEntrance employed advanced code optimization techniques to push a lot of digital traffic through a very small data pipe”.
The eternal bugaboo of digital audio, jitter, has not been ignored either. “DACport’s JitterGuard™ clock management system uses a military spec clock oscillator with 10ppm precision” to clean up jitter from the USB data stream (while simultaneously buffering that stream) before the DAC. Jitter is rated at an outstanding 1 pico seconds, a stat that puts pretty much any CD transport to shame (my Audio Alchemy DDS pro CD transport via its i2S output, by comparison, had a jitter spec of 5 pico seconds. Over S/PDIF it was 35!)
And the headphone amplifier is no afterthought either. Amazingly it’s a class A design with no capacitors in the signal path. Being class A the DACport runs quite warm, almost hot when it’s driving thirstier headphones like my Sennheiser HD 650s. The specs here are also very impressive: Dynamic range is 113 db, THD is 0.0018%, noise floor is rated at “7 µV RMS (A-weight), max gain”. On paper, this is one very, very quiet and dynamic little amplifier.
And, not surprisingly, the DACport sounds as good, perhaps even better than its stellar numbers suggest. In fact, as soon as I plugged it into my desktop system at work for some casual listening and break-in, I noticed the difference. It replaced a Headroom Total Bithead I was running between my MacBook Pro and a Mackie mixing board (which in turn was feeding a pair of Mackie powered monitors). The sound immediately reminded me of what I’d heard from the Bryston BCD-1, which I had previously reviewed (and loved, by the way). Robust, solid, punchy, dynamic, coherent, cohesive and very “un-digital” were the adjectives springing to mind as I listened and worked. The Total Bithead was not re-introduced into the system.
Switching back to the Sennheisers, the Bithead proved to have a little more gain, but still couldn’t match the bigness, boldness and smoothness of the DACport. Even if it had to work a little harder, the DACport could drive the Sennheisers as loud as I could stand, remaining clean, dynamic and musical all the way. The Bithead had a tonally darker presentation that was warmer by comparison, which some may favour, but I preferred the DACport’s leaner, cleaner sound.
Ditching headphones altogether did nothing to diminish the DACport’s strengths. In fact, it revealed even more. I was amazed at the quality of the sound with the DACport feeding a pair of AudioEngine A2 desktop speakers (this time running Pure Music, an audiophile music player that works with iTunes – review forthcoming). Turn up the wick enough to get the AudioEngines to truly light up and you’ll be rewarded with amazingly smooth, easy, very detailed, surprisingly analog-like sound. A big soundstage too, well focused and clearly defined, stretching across the width of the desk and beyond. And, inevitably, the same robustness and coherence that I heard every time from the DACport. The simplest and most telling comment is, perhaps, that I just kept wanting to turn it up!
At $399 the DACport is something of a no-brainer. It’s easy to use, sounds like it should be far, far more expensive, can drive difficult headphones with relative ease, is portable enough to use almost anywhere (although it won’t work with an iPod like the Bithead, you’ve got to have a computer, but the company has developed a way of using with an iPad), and can be used to shockingly good effect in a speaker based system as well. As I discovered, when mated to a good pair of powered monitors and a computer playing high resolution music files, it can form the backbone of a fantastic sounding, budget-friendly system. If you’re an audiophile with a computer, you want one.
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