I had a chance to briefly compared the HifiMeDiy Sabre USB DAC (UAE23) and AudioQuest DragonFly, both are USB DAC based on Sabre DAC. UAE23 is using Sabre ES9023, as for the Dragonfly I'm not sure of the model of the Sabre DAC chip.
I bought the UAE23 in May 2013, and the Dragonfly I borrowed from my brother. Equipment used for testing:
ASUS Eee PC 1215B Notebook, Windows 7 Home Premium 64 bit, Foobar 1.29.
Yamaha Headphone HPH-200.
Songs: Some Classical Albums, Paul O'Brien - Walk Back Home (Stockfisch Records), & Chesky The World Greatest Audiophile Vocal Recording.
Although sound signature is individual preference, it is pretty clear that Dragonfly is technically better than UAE23. Dragonfly is much louder, faster transient, more impactful, better perceived detail and clarity. Playing same song, 55% Dragonfly volume is about equal to the 100% of Hifimediy volume. So for driving high impedance phone, Dragonfly has more voltage to offer. I did try HifiMeDiy UAE23 with my T1 and HD800, although it manage to achieve enough loudness for casual listening at 100% volume, but for some recording it might not be loud enough on high impedance headphones. So for loudness, Dragonfly clearly wins. I'm amazed how Dragonfly can achieve so much higher loudness driven from the same USB port.
Tonal balance is very good from bass to treble, although treble might sound a tad too bright with bright headphones. The Yamaha HPH-200 is a tad bright, but the treble is still alright with Dragonfly. But I can imagine, I don't think I will use my Superlux HD681 or HD669 with Dragonfly.
On Dragonfly, music is more lively and energetic, with better power, transient, punch, and clarity. Dragonfly also sounds more airy on classical pieces. But it also might sounds too aggressive if paired with aggressive sounding headphones, which can also lead to harsh sound, depending on the headphones and the recording. But on classical and audiophile recordings, Dragonfly shines.
Dragonfly supports all sampling rate from 44.1k to 96k. The Color indicator of the playing sampling rate is also very useful to make sure that the WASAPI driver works properly on Windows 7, to set the DAC's sampling rate to match the song's sampling rate.
The LED color on different sampling rates: 44.1k - green, 48k - blue, and 88.k - amber, and 96k - pink.
One important note, Dragonfly support 88.2k while hifimediy USB Sabre DAC doesn't support 88.2k. So if you are WASAPI fans like me, we cannot play 88.2k with WASAPI on hifimediy USB Sabre DAC.
One thing I don't really like from the DragonFly build, is the rubbery coating on it's body, which usually doesn't last very long till it become sticky.
HifiMeDiy Sabre USB DAC (UAE23)
Smooth and musical, I think is the best way to describe UAE23 sound signature. Although not as technically excellent as Dragonfly, I do really like the sound signature of UAE23, especially for casual listening with IEM. UAE23 sounds smoother than Dragonfly. The treble is so silky smooth and really2 nice on vocal. With treble rich recording such as some of the Stockfisch recordings I have, I prefer the UAE23 sound signature over the Dragonfly, especially when using my favorite IEM, JVC HA-FRD80, which has clean (analytical) and mild V shape tonal balance. Although depend on pairing, but the smooth sound signature of UAE23 is really music to my ears. Especially for closed miked vocal on modern music, the smooth sound signature is actually preferable. I have other more expensive DAC to compare with, such as Mytek Stereo 192-DSD DAC which also use Sabre DAC, Dr. DAC2 DX, etc, and I really amazed how HifiMeDiy Sabre USB DAC (UAE23) can achieve such a high quality and musical sound signature at this price range.
Bass and treble are very well extended. Bass is big and deep, a tad more than natural (which I like). Mid and Treble are silky smooth. Treble never sounds harsh even when paired with rather bright headphones. Sweet and nice sound signature.
Detail is very good on UAE23, although Dragonfly still wins, but I have no complain with detail retrieval ability of UAE23. I'm rather picky with detail, it is very important for classical music and complex orchestra, and so far UAE23 delivers good amount of detail for all the music I played through it.
Imaging is excellent on both DACs, never feel small and congested. Imaging is wide enough, good depth, good sense of space, and realistic presentation with very good instrument separation.
I bought 4 units of UAE23, for me, and my friends. One of them has more than $ 100k high end setup in his home, one is a senior audiophile, and the other one is a sound engineer. Regardless the price, we all satisfied with the sound signature of UAE23. I even prefer the UAE23 sound signature over my new toy Fiio X3.
Some cons on the UAE23, mainly is the lack of support for 88.2k sampling rate. I have many 88.2k albums :(
During silent, a very soft noise can be heard using sensitive IEM, but very soft, not to the level of annoying. The lack of sampling rate indicator is also something that can be improved on UAE23, to make sure the WASAPI driver works. Maybe a drive issue, on my office HP laptop, HP Elitebook 2560p, Windows 7 Enterprise 64 bit, I always have sampling rate mismatch distortion noise when switching from one sampling rate to another sampling rate. Same foobar with WASAPI (both WASAPI event and push). So whenever I change album with different sampling rate, I have to unplug the UAE23, and plug it back again to solve the problem. The distortion noise sounds like soft clipping noise.
Both HifiMeDiy Sabre USB DAC (UAE23) and AudioQuest DragonFly are excellent DACs, regardless their price. They both have different sound signature to suit different musical preferences and recordings. Dragonfly is better with fast and rhythmical music, better impact and punch, more energetic. While UAE23 with it's sweet and smooth sound is very nice for Jazz and vocal. I found both are good with classical, with Dragonfly being more airy and better perceived detail.
As for build quality, no contest here, Dragonfly is much better, solid and high quality build (hopefully the rubbery coating will last), while HifiMeDiy UAE23 feels cheap with it's DIY plastic case. But for me, what important is their sound quality which is very good and satisfying :)
Update 30 August 2013:
Regarding the distortion every time I switch from one sampling rate to a different sampling on my HP Elitebook HP2560p laptop (foobar 1.2.9 with WASAPI), I found the problem is not with UAE23, but with the USB port of the HP laptop that seems not very compatible with the UAE23 tenor chip. Because I don't have that problem on my desktop PC and my ASUS laptop. On my HP laptop, I installed a PCI Express card to USB 3.0 adapter, so using a different USB controller, and UAE23 works fine with the USB 3.0 port.
Update 17 September 2013:
After spending more time with both Fiio X3 and UAE23, now after burnt-in and used for more than 1 month, Fiio X3 sound has been improved, more natural and musical, no more harsh treble as when new. So now, overall, I prefer the Fiio X3 sound signature than the UAE23, as being more natural, detailed, and more powerful. UAE23 does lack in driving power, and more suitable to be used as DAC, while still providing the possibility to drive directly from the output, some easy to drive dynamic IEMs, for less demanding music (less of explosive bass).
Update 23 January 2014:
Have been testing both Dragonfly and UAE23 recently, with some BA drivers IEM:
UE TF10 (3 drivers)
ATH-IM01 (1 driver)
ATH-IM02 (2 drivers)
ATH-IM03 (3 drivers)
ATH-IM04 (4 drivers)
While Dragonfly sounds with flying colors on those BA drivers, UAE23 failed completely.
UE TF10 & ATH-IM04 sounds muffled with UAE23, while the ATH-IM01 & ATH-IM02 sound harsh and metallic with UAE23. The ATH-IM03 still can be considered ok and acceptable. The sound difference with Dragonfly for some BA IEMs was very obvious. The sound made me and my friend wondered what was wrong with the UAE23. But when we tested dynamic driver IEMs with the UAE23, we tested JVC FXD80, ATH-IM50 and ATH-IM70, the dynamics sounds fine. I guess UAE23 output impedance maybe pretty high. It is alright with dynamic, but doesn't always match the BA drivers. I heard BA drivers impedance over the frequency spectrum usually not linear, and high output impedance on amp might cause severe unbalanced frequency spectrum.
Dragonfly output impedance is actually not very low, almost 5 ohms as I read somewhere, but it sounds good with the BA IEMs listed above.
So if you plan to use UAE23 for BA drivers, please be careful, if possible try first before you buy.
Update 24 January 2014:
Curious with the matching of UAE23 with BA drivers, I did some measurement on the output impedance of my DACs and amps.
The result, UAE23 output impedance is astonishingly high, more than 200 ohm
I didn't believe it in the first place, I thought I made some mistake in the measurement, but I re-measured many times, it is consistently high above 200 ohm.
While the new Dragonfly I bought from Amazon for $99, version 1.0c, output impedance is only around 0.4 ohm. Maybe DF v1.0c version has lower output Z compared with the DF v1.0 which I remembered was around 5 ohms mentioned else where.
Some other DAC I measured, Centrance DAC, Output Z: 9.78 ohm which is according to spec on it's web.
With this measurement, IMHO Hifimediy UAE23 should be used as DAC, and not a proper DAC + Headphone amp.
Edited by earfonia - 1/23/14 at 10:29pm