Empirical Audio Off-Ramp 3 and Overdrive USB DAC (TAS 200)

Top-Tier Computer Audio

Computer audio has changed during the last several years from something that concerned only recording engineers to the most exciting sector of the high-end-audio market. Audiophiles have discovered that using their computer for music is the most cost-effective and sonically superior way to access, distribute, and enjoy their digital music files. This burgeoning field has made it possible for a new generation of technologically nimble companies to surge to the forefront of the audio industry.

Empirical Audio is one of this cadre of small manufacturers dedicated to producing state-of-the-art computer-audio products. Its current offerings include the Off-Ramp 3, which converts USB audio into S/PDIF, AES/EBU, or I2S signals, the Pace Car 2 Re-clocker, which de-jitters and re-clocks S/PDIF or AES/EBU digital signals, and the Overdrive USB DAC, which converts digital audio signals into analog audio. Empirical products can be used alone or in combination with each other. The design goal for all Empirical products is, “to create products that are affordable, and yet push the envelope of performance.” We will look at two of Empirical’s offerings.

Steve Nugent, Empirical’s owner, designer, and chief bottle-washer, started the firm in 1996. His first products were primarily cables. In 2002 Empirical began modifying electronics. According to Nugent, reverse-engineering “was a learning experience for us, providing us with a lot of ‘dos’ and ‘don’ts’ as well as giving us the opportunity to experiment with a lot of different capacitors to determine which sound best.”

In 2005 Empirical began offering computer digital products including the Off-Ramp and Pace Car Re-clocker, which were so well received that by 2009 Empirical discontinued all modification services and focused entirely on manufacturing. Empirical has garnered a reputation as one of the leaders in high-end computer-based audio with its products being compared to much larger and more established companies such as Weiss, Benchmark, and Bel Canto. The big question is whether such a small company can really make products that compete successfully with the market-leaders.

The Off-Ramp 3 USB Converter

For audiophiles who’ve already assembled a great conventional stereo system, computer audio presents a major conundrum—should they replace their current DAC, which does not support either USB or FireWire digital inputs, with one that does? Recently several companies have introduced “bridge products” that allow audiophiles to keep their current DACs by supplying a pathway from the computer-only digital formats of USB and FireWire to more universal digital audio formats such as S/PDIF, AES/ EBU, TosLink, and I2S. The Empirical Off-Ramp 3 is such a product—USB goes in and all the legacy digital formats come out.

Although Empirical Audio has been offering the Off-Ramp for only three years, it is already on the third iteration, hence the name Off-Ramp 3. It comes in three different versions, the $699 standard, the $999 Superclock 4, and the $1499 Ultraclock. Any version can be outfitted with a Canare 75-ohm BNC connector for $20 or a NextGen copper RCA output jack for $60.

The Off-Ramp not only converts USB to other digital formats; it also supplies galvanic isolation between the computer and the rest of your audio system as well as re-clocking the digital signal. Using its own internal clock—which, depending on the model, can be a standard, super, or ultraclock module—the Off-Ramp takes in the digital stream from a USB source, locks on the timing of the incoming data stream, puts it into a buffer, and then applies a digital phase lock loop to the digital stream to improve the jitter before sending it out in a S/PDIF, AES/EBU, or I2S data stream to a DAC.

According to Empirical Audio’s Web site, the Off-Ramp 3 is “designed to work with all DACs and surround sound receivers and processors. There are no drivers or ASIO to install. It is compatible with any Mac OS or PC running Windows 7, XP, or Vista. It works with most formats and music players on PC and Mac, including Foobar, Jriver, WMP, iTunes, and Winamp.” What this all means is that the Off-Ramp is a true plug-and play product. All you have to do is attach the USB cable from your computer to the Off-Ramp and then attach a digital cable, be it coaxial S/PDIF, AES/EBU XLR, or I2S, from the Off-Ramp to your DAC and you’re all set.