Some may accuse me of being a bit of a Nuforce fan, and to be fair I sort of am given the amount of their gear that I have owned and/or reviewed. I have enjoyed their products for many years, and their customer service has been excellent for me. That said, I don't give glowing reviews just for the sake of it. I do my best to remain impartial and informative, with splashes of subjective impressions sprinkled throughout.
So with all that said, let's move on with my review of the uDac-3. It comes in the standard functional packaging, not plain, not super fancy. Someone in their packing department still has some sort of tape fetish as every side of the inner packaging is sealed in those same circular sticker tape thingies. This has no real bearing whatsoever, and in fact I'm probably the only one who notices this and is for some reason innately amused/annoyed by it. Moving on...
If you've owned or handled a uDac-2 in the past, you'd be hard pressed to tell the difference between that and the latest 3rd revision. The only notable difference is the change in usb port on the back (from USB-B aka “printer usb port” to the mini-b... or was it micro? bah I can't tell anymore). The usb cable supplied is slightly thinner than the one that came with the uDac-2, but not flimsy by any means.
If you've never held a uDac before, well the thing is tiny and fits in the palm of your hand. Smaller than a credit card. It's reasonably light but doesn't feel flimsy; there's enough heft to make it feel substantial. The jacks likewise seem well built and don't suffer from any extraneous wobble. You have a usb input, and for outputs you have: headphone, line-out (RCA, volume controlled), and spdif (coax). Power is turned on with the initial click of the volume knob. Of note, this only applies to the headphone and RCA output. The coax output is always on. Plugging in headphones will mute the RCA outputs.
The pot itself feels solid and smooth. No scraping or scratchy movement. There does exist a very slight channel imbalance at the very lowest levels, but this is pretty much present in every analog taper pot that I have ever heard so no biggie there. The imbalance is only present at levels where volume is practically non-existent anyways.
The Sound - Headphone Output
The overall sound of the uDac-3 is pleasing and about what I'd expect from a ~$125 unit. Is it a step up from the uDac-2? Perhaps marginally so, but I wouldn't be able to tell without direct A/B'ing, and at times perhaps just a sidestep.
There is plenty of gain on tap. A typical headphone with high sensitivity will blow out your ears before your reach 12 o'clock on the pot. With iems you might get to 9-10 o'clock on the dial. On my heavily modded and damped T50rp, the pot maxed is uncomfortably (though not quite earbleedingly) loud. With iems,
The bass is solid but a touch fuzzy, which almost makes it feel like there's a bit of bloom which adds warmth and rumble but takes away from the strict impact. Kick drums feel a bit slower, but electronic bass hits the gut. It's similar here a bit to the HDP, though the HDP has better control while at the same time adding more body.
Through the mids everything is good; not much to say here really.
The treble is ok. Not super resolving, but it should be adequate for most. Crowded fast passages (speed metal comes to mind) come out a bit muddled. The HDP treble isn't the best either, and the udac3 is a bit smoother while the HDP is a bit more strident up top.
Of the various headphones I tried, I feel the Fostex T50rp deserves special mention as an exceptionally good pairing. There was good body and impact, and the whole thing just grooved very well together.
In general, I found the performance actually better with iems, with the caveat that you don't get much play on the volume dial (thankfully the dial is sensitive enough for minute adjustments, but you still have to have a light touch). With iems I felt that both the bass and treble clarity improved, with more shimmer (but without extra edge) up top and more meat on the low end without becoming flabby.
The Sound - RCA Output vs Coax Output
While not exactly accurate, I did my primary comparison here feeding the RCA and Coax output into my HDP and flipping back and forth (volume matched, of course).
As a dac, I find the treble performance has better clarity and perhaps getting into just barely edgy territory. The rest of the spectrum feels about the same except for the sub bass which also seems to have improved in clarity. Down to 40Hz it feels as though there were almost a bit more kick right at the end.
Compared vs the HDP dac, it's really no contest as the HDP slaughters it across the board.
Acting as spdif bridge and feeding into the HDP, the HDP sounds better than when it takes usb directly, with more clarity and crispness in the upper mids (vocals). However, I have the U192 bridge in the LPS power supply that I normally feed into the HDP, and that standalone does a better job than the uDac3, as it feels blacker and portrays a better sense of depth.
I do not currently have any DSD music to test this feature. And besides the point of which... I'm just going to straight out say that I think the whole DSD thing is hogwash. There's a debatable benefit in the studio where you can have dedicated hardware and setups, but in a home setting it is not really practical unless you're building a second sub-system where neither the two will touch. If you like it though, hey all the more power to you. Those files were probably remastered in the process of conversion to DSD anyways, so any comparisons are moot anyways. Oops did I say conversion? I mean it probably was fully processed in DSD to begin with right? Not just converted, then remastered, then reconverted? Yeah, ok, carry on.
This may be a non-issue for some, but it affected me quite a bit and thus I feel it prudent to mention here. Others have reported no issues, so it may just be my particular combination of software/hardware. I am running Windows 7 on my Lenovo laptop, primarily using JRiver Media Centre.
For the life of me, I could not get the uDac-3 to play 24bit files using any bitperfect method. The FiiO e17 had no issues whatsoever; it was literally plug and play, pick WASAPI, done. With the uDac3, it just wouldn't work. I eventually tried ASIO4ALL and that seemed to work, but I would still get occasional pops and stutters.
Related to this I also encountered severe stability issues. While playing music (even in direct mode), I would get through a few songs and suddenly JRiver would freeze. This was fixed by simply hitting stop then play again, but as time went on the freezes becomes more frequent until I couldn't get through a single song. As before, moving to ASIO4ALL and updating from JRiver 16 to 18 seemed to fix the freezing issue, but I still get the pops and stutters.
As near as I can tell, the pops and stutters only happen when my computer is “thinking”, such as loading a webpage or doing a search in my media library. Why this only seems to affect the uDac-3 and not my other devices, I do not know. It is likely due to some sort of funny combination of software and hardware on my end, but that's my best guess as I have been unable to track it down any further.
If I leave the computer alone, it plays music just fine.
So I have to ask myself whether this is a good product for $125? The answer is yes. Is it a groundbreaking product for $125? Eh, not anymore. A couple years ago when the uDac2 came out, it would have been a hearty endorsement from me. Good sound, nice preamp, spdif bridge, all in a compact package for a C-note. The landscape for usb dac/amps has become extremely competitive however, and these days you can have more for less, or more for more as the case may be. The FiiO e10 makes for tough competition with similar size and feature set. It sounds not-quite-as-good-but-close in my opinion and isn't as well built, but it's quite a bit cheaper which matters for those in this budget segment.
If you're willing to move up a bit in size and/or price, perhaps don't need the spdif bridge, well the options are large and I can't even keep track of all devices coming out these days. In any event, it's well worth doing your homework in this segment. I'll only mention two that I currently have in my possession for direction comparison. The FiiO e17 sonically I think it is a tad better, and is of similar price. It's about twice the size though, and has more inputs while offering less outputs. The iBasso D10 (precursor to the D12) is like the e17, a bit bigger yet, and to my ears bests the udac3 as well, but cost twice as much when it first came out.
- yes the uDac-3 is a good buy, if you can use all the features and appreciate the small form factor
- do your homework on other options if you don't need all the particular features
- upgrade from uDac-2? Nah
Edited by Armaegis - 12/16/13 at 11:14am