Disclaimer: nuforce graciously supplied the uDAC5 for the purposes of a forthcoming review at Headfonia. the uDAC5 goes for roughly 200$. It does DSD up to DSD256. You can find out all about it here: uDAC5 USB DSD DAC.
The uDAC5 goes for peanuts. It is pretty enough to write about to be the subject of this macro/normal lens shootout. It is well built, nicely branded, and compact. It converts USB signals to RCA stereo and coaxial SPDIF for outboard DACs and amps. It gets plenty loud, too: posting absolute volume levels roughly in the neighbourhood of an AK380. At those levels, however, IMD, THD, and stereo crosstalk numbers ramp up beyond reason. Its loudest stable volume is about a half decibel louder than an iPhone 6’s maximum, which is enough for me. If your iPhone is behind a EU volume cap, the uDAC5's power will surprise you.
It also holds load into test signals nearly as well as an iPhone 6. Rub and tug between the two occurs most obviously under load. It loses its cool under the load of an Earsonics SM2. THD ramps up roughly 89x over base, unloaded scores; IMD by roughly 40x. Of course, no one listens to their SM2 at such volume levels. And even if they did, neither even reaches distortion levels of 1%, whose audibility is questionable. Similarly inaudible are the 0,5dB dips and waves in loaded frequency response curves. There's no dissembling the uDAC5's hiss. It is louder than every desktop DAC or amp I currently own, which, for a USB mains-less DAC/headphone amp, is surprising, and for sensitive-eared listeners, audible when music levels are low.
That aside, its power, its clear and smooth signature, and its brilliantly balanced attenuator, are great for both earphone and headphone use. Bass is weighty, and both stereo and y-axis instrument detail, while not deeply layered, are lively and engaging.
That hiss though…
Relevant RMAA measurements:
NL - no load
SM2 - Earsonics SM2
ES7 - Audio Technica ES7
DT880 - Beyerdynamic DT880/600
24-bit TARGETS and loads +6dB (volume matched to the iPhone 6).
24-bit summary (volume matched to the iPhone 6).
The uDAC5 is a great design. It’s not as powerful as a Chord Mojo, or Grace m9xx. It hisses far more than Cozoy’s Rei - not to mention an iPhone 6. But it is easy to use, smooth-sounding, with great polar extension and pretty solid loaded drive performance.