Introduction
I have received the Yulong DAH-1 dac/amp combo as a review unit from the generous Head-fi'er Minivan, and I have given it the role of of alternate rig / sister's rig.
I received the Yulong at the end of December, but quite a few real life concerns reduced my presence on Headfi (and Internet in general) and I have not been able to complete the review until now.
I have randomly got to read the comments of a few people in the related giveaway thread, with not so "polite" (nor informed) comments about the delay I have incurred in. I don't want to deviate the subject of this thread, but while I can understand the frustration of one for not being able to secure a "toy for review" (or,as it has been called, "free gear"), coupled with the fact that the actual reviewer hasn't shown up for a while, this shouldn't allow people to use rude/random expressions without knowing any facts. I have been surprised to see some people talking so randomly of being disappointed by "people of good reputation": from these people, I don't remember having received any single pm asking if all was right, like I have personally done with others during the years in comparable situations, for what I call sense of community. Honestly, that very "good reputation", built in the years, should deserve some credit since few wouldt be willing to spoil that for a piece of kit (doesn't matter its value, and it's not much here money wise).
Minh, the former owner of the DAH1, has been kind to offer me all the time I needed to complete the review and I thank him for both the privilege of receiving the DAC, as well as the patience he showed with my slowness.
Since I don't think it's of interest to the majority of readers to further bother with the aforementioned backstory, after this kind of "introduction" I believe it's more correct to concentrate on the actual subject of the review.
The Yulong DAH-1
The DAH-1 is a DAC/headphone amp combo, where, surprisingly for the cost, not only the DAC is very good, but the amp part itself is pretty clean and very powerful. It has usb, coax and optical inputs. I have used it mostly with coaxial cables (I am a strong believer of digital cables, although quality isn't always related to price), just like I do with the Melior Bitstream and did with my former Assemblage DAC3.0.
The DAC has already been reviewed around and is considered slightly bright, and "missing the ultimate bass authority". I wish to concentrate on such aspects as deeply as I can in order to describe what kind of brightness can be expected, as well as how its other features impact the sound.
The DAC alone is especially clear in the lower treble, and provides exceptional layering among the instruments and samples. If offers both high time resolution and spatial resolution, to a degree that's higher than average for comparatively priced or more expensive products. I don't think that it enhances sibilance considerably, so I would expect the peak to not reach the middle treble. The Yulong's layering capabilities exceed those of the Melior Bitstream and, by memory, are comparable to those of the Assemblage DAC3.0 (which uses what's considered the best DAC chip from a technical point of view, the BurrBrown DA1704).
The soundstage of the DAH1 is pretty wide and imaging is very clear and precise, and just as said above, well layered spatially. Unfortunately, the DAC's lower treble peak also makes for a less pleasant contribution to vocals, since it tends to enhance a sort of electric glare / "electric wrinkles"-effect to many voices. This is especially apparent with Mp3 (even if I only used V0 or 320kbs ones), and also happens sometimes with lossless music. By direct opposition, the Bitstream produces the best, warmest and most realistic vocals among the DAC's I have owned, and doesn't enhance any glare nor "digititis" (as someone I can't remember, once, nicknamed such digital glare).
From my listening sessions, I think that the bass on the Yulong goes deep when necessary and doesn't really roll off. Where the Yulong doesn't have the last word is in organicness/wholeness, since the midbass is a bit under-represented... It might also be a relative effect of the "lower treble vs midbass" balance. I wouldn't call the lower midrange juicy either: in fact, with neutral/brightish headphones, it risks to take away some necessary fullness from vocals.
I prefer the tone of the Melior Bitstream to that of the Yulong, since I consider it more correct and true to life. In fact, when I had the Stax SR-X Pro, the Bitstream was the only DAC that could make those Stax monitors sound colorful and "life-like" instead as ghastly and empty tonally, so it's to be expected that most dac's fall short where the Melior conveys all its philosophy. Still, the achievements of the Bitstream (even if it's a 1000usd dac) come with a trade-off, and the Yulong offers a better sense of resolution and detail retrieval, which is great for a DAC that costs 3 times less than the former. The Assemblage DAC3.0 is the most polished and "neutral" of the three and in a way the coldest, and prone to sibilance, but probably the most precise and tighter in its bass balance. The Yulong manages to sound less "cold" than the Assemblage thanks to its upper midrange/lower treble tilt, that makes it "exciting" and "brightly" emotional, although, as said, vocals can suffer for such behaviour (and they are by far the most affected "instrument" in the songs).
When using both the Yulong and the Bitstream to feed my CKKIII amp, a good way to help the Bitstream shorten the gap in detail retrieval with the Yulong is to use bright interconnects. This makes for a good tradeoff in tone vs resolution to the advantage of the Bitstream, where the DAH-1 is less tweakable since it already starts bright and, in opposition, enjoys warm interconnects like Belden's (which I have tried with my DAC/Amp combos), although producing a less noticeable result.
The main limit of the Yulong, to me, isn't the lack of bass (the midbass shyness it's not that severe, and makes much music just clean), but the very same treble brightness (I'd say 3-5 kHz) that makes for such an exceptional level of detail: its drawbacks, as said, concentrate around vocal reproduction where too many singers tend to have "shiney" voices.
The Yulong DAH-1 amp section, just as suggested by Skylab, offers "more of the same", in that the treble shines even more apparently and doesn't couple perfectly with the DAC's signature: probably a darker amplification circuitry (hybrid? Let's dream for the future...) would have balanced things more correctly.
Some internet reviews consider the DAH-1 to be very good with Sennheiser HD580/600/650 phones. This is true for a large part, although not completely (I did try HD580 with it): the Senns to me aren't the representation of neutrality, I consider them a bit dark, boxy, and with some fat bass that often misses the pacing of the music and adds to the sense of slowness. I know that some people think that a super amp might get rid of some bass "looseness". Based on what I have available, neither the CKKIII nor the Yulong amp section can. I also know of people using tube speaker amps with their H580 and they also think the bass looseness doesn't really go away. The DAH-1 amp does some good things to make the Senn's upper end more lively, though. In such regard it matches nicely with the HD580.
I have heard the HD800 separately in a shop, but going by imagination I wouldn't use them with the Yulong DAH-1, since the HD800 are very bright and sibilant. To be honest, I don't think that even the Bitstream source would solve completely what I find wrong in the tone of the HD800 (I think some of their flaws are hopeless, at least for my taste, which is a pity since I loved the texture and the size of the headstage).
The headphone out of the Yulong is quite, although it starts hissing with sensitive IEMs.
I don’t’ like the Yulong DAH-1 with my Smeggy-fied Thunderpants in standard configuration (one bass port closed): the combo sounds with thin vocals and slightly feeble bass, while the higher part of the spectrum, already raised with the TP’s, tends to sound more close to the listener. Keeping all the TP's bass ports open adds body to the sound.
I nice surprise was a certain IEM / Yulong combo: my current Etymotic HF-5 sound godly with it, with a catch. I have learnt that cutting the third flange of the HF5 eartips has a special effect, since it places the internal tube’s opening at the same level of the eartip’s opening, thus ruling out any narrow path the sound waves should encounter after exiting the earphone. A narrow path like the rubber tube of an eartip would decrease the bass dramatically and has show me, during the years, that treble also rasies. I think narrow paths with IEMs act as a bottleneck against the lower part of the sound spectrum, placing a resistence to those frequencies. The Ety HF5, without all my previsions, sound awesome and organically with the Yulong and essentially everything is perfect, retaining all the magic multilayered detail presentation that’s the main strength of the DAH-1.
A final note is about digital cables: while both the Bitstream and the Assemblage react to digital cable swaps (the differences are also very noticeable, for example when going from the Belkin Synapse Platinum digital to the two different Moray James I have, and the other way around), to me the Yulong is less sensitive to changing digital cables and retains its sonic signature more consistently.
I do think that the Yulong is a very good purchase for the price, although I would mainly use it for warm cans (either dynamic, orthodynamic or electrostatic), since they would tend to compensate it's flaws. Headphones enhancing the highs (like much audiophile gear does) could end up not sounding organic and "real" enough with this DAC.
A personal point of interest would be to match the Aude'ze LCD2 with the Yulong because, by seeing the frequency response graph of that headphone, as well as the related sonic impressions, I think the combo would be scarily good in most (if not all) regards, but that's another matter (and dream).
Tony
Edited by antonyfirst - 6/3/10 at 2:04am
