Anyone browsing this forum has probably already had their formative experience with music. Maybe it was a live performance. Maybe it was a demo at an audio dealer, or a nice car stereo, or maybe even a pair of headphones. Whatever it was, it sparked an interest into quality music reproduction equipment, and here we are pursuing that goal.
For me it was a combination of things. When I was a child my dad frequently played jazz, blues, and classic rock at very high volumes through some huge Altec Lansing 846A Valencia speakers, powered by a McIntosh MAC1700 integrated. As I got older my brother started DJing, so I constantly heard him monkeying with vinyl on his Technics 1200 setup. I did start playing drums at a young age but I don’t believe the school band did as much to influence my initial love of music as the other “non-live” sources.
That brings me to the topic of my current review. My nephew is in his late teens and is just now discovering his own love of music. His tastes are a little different from mine, but I’m just glad to see him taking an interest. Apparently his job (graphic design of sorts) allows for him to listen to headphones most of the day. He had been listening from his iPod until he decided that the soundcard on his PC sounded just as good and was more convenient. He started with the Creative EP630 and then upgraded to the AKG K81DJ, which is pretty respectable for a beginner. I decided to reward his enthusiasm by picking up an all in one unit that can extract some good sound from his PC and deliver it to his headphones.
My budget for this was $200-300. It needed to be small enough not to invade his desk, and powerful enough to reasonably drive most headphones including IEMs and full sized models. I already had experience with two very good choices: the Matrix Cube and Audinst HUD-mx1. But I decided to try something new and ended up with the Yulong U100. I really enjoy my Yulong D100 and A100 so I figured the U100 would likely be pretty good. Besides, he wouldn’t know the difference since he doesn’t have anything to compare to except for his integrated PC audio.
I’ll start with the description Yulong gives of the product. I’ve cleaned it up a bit to compensate for the slightly awkward language of the original, likely due to translation:
U100 is a high performance, compact size USB decoder and headphone amplifier. It features RCA line out as well as 3.5mm line in, so it can be used as a regular USB DAC, or used as a stand alone headphone amplifier via the 3.5mm line input. The U100 is designed and optimized for high performance USB decoding, so there is no other digital input available.
The U100 has an elegant, compact housing (160*110*30mm) which is carefully made using aluminum alloy, and it weighs only 0.48kg. By simply connecting it to a PC via USB, then using it to drive headphones or active speakers, it is easy to build a high-quality PC Hi-Fi system.
The power supply of the U100, developed by ShenZhen YuLong Electronics Co.,Ltd, utilizes an audio grade, special designed switching power supply with high-performance and very low ripple, which assures the U100 has sufficient driving ability and excellent performance in a small size.
The USB data is received and processed with the high-performance Tenor TE7220L (USB2.0/24Bit/96KHz), and the decoded I2S signal goes directly to a Cirrus logic CS4398 (120dB dynamic range, ultra low THD+N at -107dB) for DA conversion. The selected components in the analog circuit include: ADA4075-2, which is the latest technology by ADI; High-precision SMD CBB capacitors from Panasonic and 0.5% SMD resistors. The power amplifying is done by ADA4075-2 plus a "Diamond" transistor buffer circuit. This simple, efficient and direct coupling mode of the circuit assures a minimal signal path length, avoiding signal interference and loss during the transmission.
With extensive listening tuning and measurement, the sound from U100 is clear, transparent, delicate and soft, natural. The high frequency switching mode power supply used is a key factor for sufficient power, low noise and good transient response.
● USB input: USB2.0/24Bit/96KHz.
● Line input (3.5mm).
● Line output (RCA).
● Headphone amplifier output (6.35mm).
● Power Supply: 6-20V DC.
● Internal high-quality switching power supply.
● Cirrus logic CS4398: -107dB THD+N.
● Compact size aluminum alloy housing (160*110*30mm).
● Upgradable firmware for USB.
● Global AC Power Supply (90-250V).
● SNR: >120dB
● Dynamic Range: 110dB
● THD+N: 0.0009% @ 1KHz
● Frequency response: 20-20KHz -0.2dB
● Power consumption: <10W
● Headphone out power: 100mW/300R
● Net weight: 0.80Kg
● Packing Size: 250*200 *70mm
That pretty much sums up the U100. There isn’t much more to say other than to mention that the 3.5mm rear panel input takes priority over USB. There’s no switch to choose between them, so a user would have to manually plug and unplug if they intended to use both inputs regularly. Apparently there is a way to upgrade the firmware that enables software volume control. I don’t see the point of that because the built in amp already has a volume control. When using the U100 as a DAC only, there should be a volume control on the amp or powered speakers being used. So either way a software solution seems redundant.
I did notice an internal jumper marked as “volume”. I don’t know what it does, but since I was getting good performance across a wide variety of headphones, frankly I felt no need to try it.
Lastly I should mention that the external wall wart type power supply is in fact required. Initially I wasn’t clear if it was necessary or just optional like it is with the Audinst unit. For this reason, the Audinst remains the most convenient choice for a truly transportable USB DAC.
The U100 arrived well packed at my house in a short amount of time, which makes me 3 for 3 getting Yulong products from eBay seller wsz0304. Inside the box we find the U100, a wall wart power supply, a roughly 5 foot long USB cable, a user manual, a 3.5mm to 6.3mm adapter, and lastly a breakout adapter to allow an RCA cable to plug into the rear 6.3mm input. This is a fairly comprehensive package that should get most people up and running. I especially like the inclusion of the adapter which allowed me to use RCA outputs from a CD player and use the U100 strictly as an amp. It’s a dirt cheap part but I didn’t happen to have one lying around the house.
I was initially surprised by the somewhat light weight of the unit. Given the metal appearance my brain told me it should weigh more. In actuality it is just about what it should be: roughly double the Audinst and roughly half the Matrix Cube. Build quality is generally in line with what I expect for a ~$240 product. My unit is silver and uses the same nice brushed aluminum faceplate as its big D100 sibling. It also shares many styling cues with the D100 such as the same volume knob and headphone jack. One area where I was a bit disappointed was the top and sides of the case; instead of the textured satin like finish of the D100/A100, here we find just a basic metal finish. There’s nothing wrong with it but it does lose some points for style. I guess that’s one area where they had to compromise to achieve the low price. Note that it is also available in black, unlike the D100/A100.
In general the unit seems built well enough. Panel gaps are tight, and I had no problem taking it apart and reassembling it (sometimes I find issues with screws not wanting to go back in, a sign of poor quality control for the casework. Not here.) Internal components are also of solid quality if not quite boutique status.
Operationally things were just as good. Volume tracked well at low settings, background hiss was minimal even with sensitive IEMs, and I had no issues connecting it via USB to any of the 3 computers I tried. Once connected it prompted an automatic install of a driver, and then I was advised that my new USB audio device was ready to go. It actually shows up as “Yulong audio” and it worked equally well with XP, Vista, and Windows 7. I never encountered an error with playback on any of the three setups. Heat was also not an issue even over extended listening sessions.
Source: Dell Mini netbook with passive cooling and solid state hard drive, Sansa Fuze with modified Griffin Powerdock (to test the line in section)
Amplification: Yulong A100, Yulong D100, Matrix M-Stage, Vivid Technologies V1
Headphones: AKG K702, Sennheiser HD600, LiveWires Trips, Grado RS1, 1964 Ears 1964-T, Monster Turbine Pro Copper, Fischer FA-003, Lawton LA7000 Lite
These are just the impressions of one guy. I do these reviews for fun, not profit, and I don't claim to be any special authority. Many people have agreed with my assessments of other gear but some have also disagreed, and I totally respect that. We all hear differently on a physical level and we all have different preferences as well, so I think it almost impossible for one person’s impressions to apply to every other person. As with all my reviews, I hope you enjoy reading them and I hope they help our hobby to some extent, but I don't pretend that they are anything more than my opinion.
This review is different from most of my others because I was on a somewhat limited timeframe. I did have what I felt to be sufficient time to form a good opinion of the unit, but I usually take a few weeks longer just to make sure I’ve solidified my impressions. By the time this is posted I will have already given the gift to my nephew. I’ve advised him to keep me informed of his opinions and any operational quirks that arise.
Before doing my listening, I asked my nephew for some examples of the music he likes. He took it one step farther and gave me a portable hard drive loaded with a bunch of his music. It had everything from 192k mp3 files to 24/96 FLAC, with the majority being at least 320k mp3. For that reason I suspect it mostly came from torrent sites, as those seem ubiquitous for people of his age. Nevertheless I had a blast listening to music I hadn’t heard in years. There was plenty of old school electronic music of the type sometimes classified as “Electro”. Stuff like Planet Patrol, Newcleus, Twilight 22, and Cybotron. There were also a diverse collection of some more recent artists that were both new and interesting to me, including The Format, Catch 22, Ayo, Metaform, Stacey Kent, RJD2, Meiko, and The Fire Theft. I can’t say that I love every track, but each of them has at least a few that I enjoyed, and the variation in style and recording quality was great for testing the U100. I also used some of my own tracks that I am very familiar with.
The U100 impressed me right off the bat by sounding quite musical. It still retained most of the transparent Yulong “house sound” that I’ve come to enjoy from the D100 and A100. But on this model it seems that things were slightly tweaked to give more of a sweetened sound. It isn’t extreme coloration, and I wouldn’t describe it as syrupy or anything, but it is noticeable.
The bass had excellent impact, with good extension and control. Compared to the A100, there was a bit of overhang with regards to decay. This is especially noticeable during complex passages and is likely a result of the power supply being less beefy than the A100. That’s not to say that it sounds bad though. On the contrary, it sounds lively and full, with good presence and clarity. If you were specifically comparing the bass performance of high end headphones, especially flagship custom IEMs, this might not be the best yardstick to use, but for regular listening I found it quite pleasing. I particularly liked pairing it with the Fischer FA-003, which I enjoy but find could use a little extra bass energy every now and again. Listening to old-school Electro music on the U100/FA-003 combo gave me a nice punchy bass kick with excellent pace; I had to fight the urge to lay down some linoleum and bust a move.
Mids were just the slightest bit lush as compared to the A100. Once again, when used in a very high end setup this might not be desirable. But considering the price that this unit sells for it is much more likely to be paired with low or midrange headphones. In those cases, the U100 mids were generally a great match. Vocals were pleasingly full bodied, guitars had a nice “crunch” to them, and piano strikes sounded warm and full. Interestingly, this slight enhancement in the presence region did not hinder lesser quality recordings the way I suspected it would. If anything the smoothness of the mids served to enhance poor recordings, giving them a bit more body and clarity than a more neutral product like the Audinst HUD-mx1 could (but more on that comparison later). Be aware though that I’m talking about relatively subtle boost here; it’s nothing like the difference between a mid oriented Audio Technica headphone and a slightly mid recessed Denon headphone (for example).
Highs were fairly present and detailed, but there was definitely a bit less energy on the top end of the spectrum. Again, I don’t mean heavily rolled off, just ever so gently tapered in a downward direction. I found it to be a good compromise, giving me a nice amount of clarity and air but also taking the edge off certain recordings that might be prone to digital glare or harshness. The downside here is that it isn’t an absolute detail monster. Still, it turned in a very enjoyable performance with everything from bright headphones to dark headphones, so once again we are talking about a mild flavoring rather than an overwhelming coloration.
Soundstage performance was respectable for the price. I got plenty of width and a decent amount of depth, making for a believable reproduction of the recording venue. You generally don’t get spectacular lifelike imaging and soundstage from a combo unit of this price, and the U100 is no exception, but I certainly wasn’t disappointed with what I heard. It kept up easily with the competition from Audinst and Matrix (again, I’ll be more specific about that later), and was roughly on par with what I would expect from a CD player in the $400-600 range.
So at this point it sounds like just a lukewarm product, right? Not so fast. Yes, there is room for improvement in each area. But taken as a whole, I’m actually quite impressed with the U100. It seems that Yulong really knew their intended audience here. After accomplishing the very neutral sound signature with their D100 and A100, they really set the bar high. A small DAC/amp like the U100 is not going to replicate that sound for under $250; it just isn’t possible. So rather than give us a generally compromised version of the D100/A100, the U100 instead gives us a different take on the subject. By anticipating the target audience and the equipment they are likely to have, Yulong has ended up with a rather unique offering that differentiates itself from its competitors.
One thing I especially liked was that the U100 paired well with almost all the headphones I tried. The specs don’t show much in the way of power ratings, but I found that the U100 could comfortably drive everything short of Orthodynamic headphones. Sensitive IEMs like the Westone ES3X had a very quiet background, and big full size models like the Sennheiser HD600 could get plenty loud. Chanel balance was nice and even as well. More importantly, I refer to the U100 pairing well in terms of making different headphones sound good. Recognizing again that we aren’t going to get a perfectly clear neutral sound in this price bracket, the U100 did a bit of sweetening (especially in the mids) and delivered a pleasing sound with most every headphone I own. In that respect it reminds me a bit of the HiFiMan EF2 or the Fournier HTA1, both of which are tube amps. The one headphone I could find that I didn’t particularly care for out of the U100 was the V-Moda Bass Freq. It’s a cheap little bass monster that I occasionally use to fall asleep to. It might be one of the darkest headphones I’ve ever been able to enjoy, and the U100 tips it just far enough in that direction to be not so fun. I’d much rather hear the Bass Freq straight out of a Sansa Clip+. It’s unlikely that anyone would be pairing those IEMs with the U100 but I thought it was worth mentioning.
Also worth mentioning is that this somewhat tube-like coloration is more a result of the amp section than the DAC itself. To test this out, I used the D100 as DAC to isolate the U100 amp section, and then used the A100 as amp to isolate the U100 DAC section. It turns out that the DAC does share the slightly warm and dark sound, but it is pretty minor compared to the amp. Used as a stand alone DAC only, the U100 will give you a lot of the same benefits as the D100, but of course won’t go as far. The amp section itself is quite good though and I imagine you would not be able to improve it until you spent a decent amount of money on a stand alone unit. That’s assuming you can live with the warm sound signature. I think it was the right choice in this case and prefer it over some other low priced options I’ve heard like the uDac, which I found relatively thin and grainy.
The obvious competition here is the Audinst HUD-mx1 and the Matrix Cube. If I had not heard those two I would probably be a lot more excited with the level of performance being attained by the U100. Still, just because a few others have achieved it, doesn’t mean it is less of an accomplishment for a small company like Yulong to join them. The good part is that they are different enough to warrant individual recommendations in different circumstances.
The Audinst mx1 is still going strong as the most neutral DAC of the bunch. In comparison the U100 has slightly more authority in the lower regions and a bit of extra fullness and snap in the mids, followed by more gently defined highs. The U100 ends up being simultaneously more laid back and engaging, concerned more with the pacing of the performance rather than the minute details. The Audinst is more focused and has a more intimate presentation, with a nice balance across the whole spectrum. Overall I think the DAC sections are somewhat different but equally good. The amp sections couldn’t really be more different though, and it would be a matter of taste which you would prefer. For many headphones the U100 is better in my opinion.
The Matrix Cube is a bit more expensive than the U100. For the extra money you get lots more inputs as well as selectable upsampling. The biggest advantage possessed by the Cube is its very expansive soundstage. It has great realism when it comes to spreading out the musicians in the performance space. The U100, while no slouch in that area, can not compete here. If we turn off the upsampling feature on the Cube the two units end up sounding very similar when used solely as a DAC. The Cube has a more lively presentation up top but the effect is minimal. As far as amp sections go, the Cube is closer to the U100 than the Audinst, but the U100 still gets the nod as being warmer and a little darker.
There’s no real loser in this comparison. Each has a valid application where I would recommend it over the others. For those who just want a solid foundation that is neutral and evenhanded, the Audinst is the way to go. Someone needing more inputs (especially an analog in for SACD or DVD-A playback) that likes a warm musical sound and values an expansive soundstage should look no further than the Matrix Cube. The U100 is my top choice for someone who will likely not be upgrading soon, who simply wants a nice low profile unit that will make anything you pair with it sound good. In fact it might actually make sense to choose the U100 over the D100 in some instances. Consider a person on a budget of around $600. Barring any future upgrading, it might be better for them to get the U100 and pair it with a nicer headphone; the headphone budget would be $350. If that same person went with a D100, there would only be $150 left for headphones. I know this is a specific example but there are plenty of similar scenarios where the U100 would be a great choice. Its forgiving nature lends itself well to all types of music and headphone pairings.
As I mentioned before, the U100 is not quite the achievement it could have been if we didn’t already have amazing value units like the Audinst and Matrix Cube around. Still, while not quite raising the bar, I’m pleased with the performance it gives. It might not be as resolving as those competitors, but it makes up for that with a very organic almost analog type sound. For someone who wants a small combo unit that makes practically everything sound great, the U100 is an easy product to recommend. It has very nice build quality and comes with a comprehensive package to get you started on your road to musical enjoyment.
This is the 3rd product I’ve tried from Yulong Audio and I have been nothing but impressed by this company. I’m not sure what else they have in development, but based on what I’ve seen I am confident saying it will be good. I’ve given the U100 to my nephew and he has nothing but good things to say about it. He has already gone through some different headphones to find his preference including Sennheiser HD555, Grado SR80, Ultrasone HFI580, and Audio Technica AD700. It’s great to see a budding music fan become more passionate about good audio reproduction, while at the same time not losing sight of the music or being too hung up on the hardware aspect of things. I suspect he will settle on a single model one of these days (possibly the AKG K701 as he really enjoyed it when he tried mine) and stick with it and the U100 for many years to come. Finding him a few years later with a bigger collection of music, and more knowledge of what he likes, but the same DAC/amp unit would be a great complement as to what gear is supposed to do for us.