When we listen to music, there’s more often than not a digital-to-analog converter (DAC) in the signal path between the source, the amplifier, and the loudspeakers or headphones that ultimately deliver the sound to our ears. Those two components can make or break your audio experience.
When your source playback device is a computer, the quality of the DAC you’re using becomes even more important. Computers are great at lots of things, but audio reproduction isn’t their forte and computer manufacturers don’t invest significant sums into the computer’s DAC or headphone amplifier; most don’t even pay much attention to isolating the computer’s audio components from the electrically noisy environment inside the computer’s case. Installing a high-end sound card in a desktop machine is one option, but you can’t do that with a laptop. That’s where Optoma’s NuForce uDAC5 comes in.
High-quality audio you can take on the go
Personal computers—both Windows and Mac machines—convert digital audio to analog and output to 1/8-inch jack, but they also send the digital bit stream their USB ports, keeping the music in the digital domain where it's virtually immune to interference. When you plug the uDAC5 into one of its USB ports, the uDAC5 will convert the signal from digital to analog and send the analog signal to both its stereo outputs (for connection to powered speakers or an outboard amplifier) and to its onboard headphone amplifier (for use with headphones). The uDAC5 also passes that bit stream to a coaxial S/PDIF port, so you can use a different DAC if you prefer.
For all it does, the uDAC5 is tiny enough to fit in the palm of your hand. It’s extremely light at 3.53 ounces, and it’s ultra-portable, measuring just 2.68 inches wide by 1.77 inches deep by 0.83 inches high. I was able to carry it in the same case as a set of Oppo PM-2 headphones. You can just as easily slip it into a jacket pocket or purse.
Hi-res music file support, including DSD
The heart of the uDAC5—an ESS Sabre Hyperstream DAC—is housed inside a gray metal enclosure, and it natively supports just about every hi-res music file format you can think of, including FLAC, ALAC, and WAV, as well as DSD files up to a maximum of 384kHz/DSD256. It can handle PCM sampling rates of 192-, 352.8-, 384KHz, and DSD sampling rates of 2.8-, 5.6-, and 11.2MHz.
Optoma The plain front panel has an analog volume control and a 3.5mm headphone jack, but there is no IR remote control receiver.
Optoma says that in contrast to its predecessor, the uDAC5 will deliver 140mW at 32 Ohms, so you can drive just about any in-ear headphones and most over-the-ear headphones. None of the over-the-ear headphones I had in-house and tested with the uDAC5 are tremendously difficult to drive, and the uDAC5 drove them all with ease and control.
Mac users can just plug in the uDAC5 and go; Windows users will need a driver that Optoma provides as a free download. Mac users will need to select the uDAC5 as their source and change the sampling rate in the Audio MIDI app located in the Utilities folder. I used BitPerfect for iTunes and JRiver Media Center on a MacBook Air, which do this automatically for me.
If you plan to play hi-res music files with the uDAC5, be sure your software-based media player supports the formats you want to play. iTunes, for example, doesn’t support FLAC or DSD. You can convert FLAC to ALAC (Apple’s lossless format), but if you want to play DSD files, you might want to consider using the cross-platform JRiver Media Center. There are a number of other software options to choose from as well.
A noticeable difference on every headphone tested
I tested the NuForce uDAC5 using JRiver Media Center 22 and iTunes with BitPerfect, though the specific examples noted in this review just happen to have been via JRiver. I also tested the NuForce with four different headphones: the open-back Oppo PM-2 and the closed-back Bowers & Wilkins P7 Wireless , Meze 99 Classics , and V-Moda Crossfade Wireless . I compared the uDAC5 to the stock 3.5mm headphone output of a MacBook Air.