Some excerpts from the reviews:Review of HRT compared to Audinst:
Review of the Youlog U100 v Audinst:
Like the MS2, the Audinst also does 24/96 over USB. But that's as far as the similarity goes. The MS2 is equipped with a PCM1793 D/A chip, which is the lesser version of the PCM1794 chip used in the MS2+. The Audinst on the other hand is equipped with the WM8740 D/A chip. Although D/A chips do matter, ultimately you can't predict a DAC's sound quality just by knowing the chip it uses, as there's a lot of variables in the design of the circuitry.
The Audinst HUD-MX1, as always, sounds very musical. With the 2-ch Beta22 and the Hifiman HE5LE, I noted no deficiencies in the Audinst's sound output. The sound is slightly warm, there is a good body and musicality in the music. The soundstage information is very good, separation very good. For sure, the Audinst still remains a very good performing DAC for the price it's selling for.
Moving to the MusicStreamer II, the first impression that strikes me is how soundstage has been improved. Most notably is the soundstage depth, where the MS2 is much more three dimensional than the Audinst. The width and the open-ness of the sound is also improved on the MS2. I am liking the improvements a lot, as soundstage performance is very important to me. The instruments are more alive and independent, where the HUD-MX1 still maintains everything fairly close together.
Furthermore, the two DACs are also different in terms of sound signature, the Audinst HUD-MX1 has a more relaxed and slightly warmer sound signature. The MS2 is more neutral, and doesn't quite have the coloration of the Audinst. The MS2 is also more lively and energetic. Treble is more decisive on the MS2, and bass is tighter and punchier. I'm not saying that the Audinst is highly colored, because it's still mostly a neutral sounding DAC, but it's warmer and more relaxed in comparison to the MS2. Depending on system synergy, some people may prefer the Audinst's more relaxed and warmer sound. The MS2 is more forward, although with a Beta22 and the HE5LE, I don't feel the HUD-MX1 to be overly laid back.
Again, little differences between the two DAC. The HUD-MX1 has slightly more low end presence, but bass punch is less tight and less punchy, where on the MS2, even guitar plucks sound more decisive and snappy than the HUD-MX1. Vocal is slightly more forward on the MS2, with richer texture, where the HUD-MX1 is smoother and slightly more laid back.
Going up to the $345 model, the MS2+, does yield some nice improvements, although they are more subtle and more in the small refinements. The MS2+ has an even bigger soundstage, a more refined treble, and slightly more midrange body for a more musical sound than the MS2. The subtler improvements is very appreciated on a highly transparent system such as the Beta22 and HD800/HE5LE that I'm using, and the MS2 sounds quite less refined and a little harsh than the bigger brother. On lesser transparent systems, I'm not sure if the difference is going to be that noticeable.
What matters more in this comparison, (at least from a practical standpoint) is how the Audinst come with quite a decent headphone out that's able to drive big impedance cans such as the HD650 and the HD800. That makes it a very convenient unit, as you don't need the clutter of another headphone amplifier. The Music Streamer II, on the other hand, is more of a purist approach. If you own a high quality headphone amplifier, you'll probably like the Music Streamer approach better, as it just give you a high quality digital to analog conversion for pairing with your headphone amplifier. Otherwise, the Audinst would be preferable, because you don't need to worry about getting an amplifier, as the built in amp is quite competent.
I'm very happy to see that the bar on the $100+ USB DAC has been raised by the HRT Music Streamer II. When you move to a bigger and more expensive high end DAC, one of the thing you notice is the improved soundstage performance, and in that area the MS2 is quite superior than the Audinst HUD-MX1, which is my previous favorite $100+ DAC
The Audinst is very nice as I can hook it up to my laptop and have a very nice system that's able to drive heavyweights such as the HD800 or the HE5LE. With the MS2, you need another headphone amplifier, another power outlet, an interconnect cable. So ultimately it depends on what you're looking for. If you already own a good quality headphone amp, then you probably want the MS2, which is the better quality DAC. If you want a simple entry level system, then the Audinst is the better choice.
Audinst v. HRT
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.
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.
HRT MUSIC STREAMER+ WITH CREEK OBH-21
The HRT Music Streamer+ was my first foray into computer audio. I was impressed with its musicality and low noise, as well as its simple operation. The Creek OBH-21 is an old standby, sort of the gatekeeper of the amp world. If an amp is not better than the Creek, I'm probably not interested.
The Audinst simply outclassed this combo in almost every possible way. More powerful in both volume and drive, more instrument separation, more natural timbre, better soundstage, more realistic attack and decay, the list goes on and on. I found myself at one point thinking the HRT/Creek combo was more musical. Eventually I discovered that it was due to the lack of top end sparkle combined with an overall dullness that took me right out of the performance and had me viewing the music from a distance. Imagine standing outside the gate of a loud outdoor concert; you are likely tapping your toes to the music but at the same time completely missing most of the details. I have a theory about NOS DACs that follows this same logic but I need to do some more listening to confirm that.
In contrast, the mx1 was giving me an excellent seat in the front section of the performance. I tried using the mx1 as a DAC and going out to the Creek and it slightly cleaned things up over the HRT but was still pretty uneventful.