Sorry guys, I should have cross-posted what I shared about the Gustard x12 vs. Aune S16 over on the Gustard H10 thread. I'm cutting and pasting it now:
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Ok, OK fellahs... I hate to do this piecemeal, but I think it's now safe to give some brief preliminaries. My H10 break-in experience has me a bit wary, but what the heck, when things are sounding good and will only get better, there is really no flag on the play.
With 13 hours in, this DAC is showing great promise. The first thing to impress me is the dynamics. Call it lively, slam, jump factor, or a punch in the face that doesn't hurt, ha love that one, this DAC has got it. That doesn't really surprise me given the Gustard approach to power supplies. The thing sports the same dual transformers and serious capacitor bank as the H10. In this case, the transformers do separate duty for digital and analog stages.
We also have a new discrete voltage regulator stage. Add these up and throw in the ESS Sabre chip and I guess that's a good prescription for dynamic energy. The really good sign is that there doesn't seem to be any annoying treble harshness with this energy. It's a wee bit hard, but not harsh. It's what I have come to expect when gear is still breaking in, so I'm very encouraged. The stage is very spacious with good imaging, easily the equal of the Aune at this point. I haven't set up for direct A-B of the two yet, so I'm going on memory here. The low bass is very well controlled with the X12, perhaps not yet quite as extended as the Aune, but definitely more defined and I mean pitch definition. I suspect the sub bass will fill in with break in time.
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The Aune S16 is extraordinarily smooth with a very natural ease to things and lots of air around images. I'm not quite there with the X12. The images seem a little less cylindrical and less air and space around them. I'm about 90% sure it will get there because it has already improved in the few hours I've been listening.
I'll tell you what though, I'm really liking the tonality of the X12. The horns have more bite and blatt and sound more like they are made of pure metal instead of some funky ceramic/metal amalgam.
I'm getting the same effect with both acoustic and electric guitars... Just great tone. I think it may be because I'm hearing more of the leading edge, the initial pluck instead of more weighting given to the following bloom and resonance propagation of the note. Maybe the Aune is a little too polite here. It's too early to say for sure, but perhaps later A-B's will help solidify my impressions.
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@stuartmc did you say acoustic guitar? hey, you got me more interested there. Perhaps you can start a new thread dedicated to the X12? I'm sure more head-fiers would be interested.
Oh yes, I am very much saying acoustic guitar. I have Classical guitar music from the likes of Segovia and Williams, Spanish Guitar stuff from Segovia, Strunz and Farah and Ottmar Liebert and then every single Acoustic Alchemy album. I really love the stuff and its my go to source when I'm trying to get a handle on tonality as well as the balance between pluck, bloom and decay.
I think starting a new thread on the X12 probably would be the right thing to do. I shouldn't be cluttering up the H10 thread with this discussion, but I just can't help myself. Listening this evening after 16 more hours of breakin is confirming many of my initial impressions, including my expectation that further breakin would flesh out the sub bass, relieve some of the hardness and put a little more air around things. Im going to give it another full day before I do more critical A-B comparisons to the Aune. Since both units have balanced out, it makes comparisons in DAC mode running into the H10, that much easier and relevant. I am not even considering the usb side of things since I don't use it all and of course I can't compare the onboard headphone amp of the Aune to the X12, since the X12 doesn't have one. The latter would be a waste of time anyway, because I have already determined that the Aune's headamp is adequate, but nowhere near as good as using the H10 with it. So it's mano a mano, DAC to DAC only.
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I like the sound of the H10 so well with the Hifiman HE-400i that I couldn't resist the urge to score the HE-560 at a nice price from a fellow head-fier. I'll probably pass along my HE-400i at an equally nice price. They will need to go to a good home with someone who will appreciate my very careful grill and pad modifications.
I had another interesting listening session with Gustard X12 last night. I was doing A- B comparisons to the Aune S16 and I was quite frustrated that with additional breakin, the X12 hadn't opened up that last bit that I thought it would. Every time I switched to the S16, I was hearing a more relaxed, natural, life-like sound. This was all about soundstage and the ambience of the recording venue, because that is what I was focusing on and was the most apparent difference between the two. The Gustard was still sounding a little too forward, with somewhat flattened images and a treble that wasn't harsh, but did have a slightly overemphasized leading edge on plucked notes. I left it alone and on continuous play for a few more hours and when I returned, I decided switch up the setup. For A-B comparisons I had the Gustard DAC sitting ontop of the H10 and my Rega Apollo-R transport perched ontop of the X12. The Gustard DAC was essentially sandwiched between two other components. The Aune S16 was sitting on the side, all by itself, with no other components above or below. I now put the X12 by itself and the S16 went into the stack sandwich.
Now back to the A-B comparison. I was using a very high resolution recording, Carmen Gomes, Thousand Shades of Blue, Live Studio 11 recordings by Sound Liaison. Wonderful ambient space, great vocal with hollow body electic guitar, upright bass and a cajon beat drum. Here is video of the actual recording session:
http://youtu.be/eXypZsHO4XQ
Now this is uber cool because you can see the set up in the studio to confirm what you're hearing and imagining on your headphones. This time the difference between the two DACs was greatly diminshed. So much so that it made me really wonder what was happening to the DACs when sandwiched like that. I was also cognizant of the fact that I might just have hit the Jeckyl and Hyde point of the X12's breakin. The H10 had done a similar mind bending transformation on me, so why should I be surprised if the X12 did the same. I wasn't going to keep switching around the setup to confirm which of the two was really causing the audible changes, I was just happy and relieved to hear the X12 sounding so much better.
After more back and forth time with different music, I came to the conclusion that the little extra air and spatiousness of the S16 was really frequency response related. The S16 has a thinner lower midrange and more resticted bass than does the X12. This makes the treble, where most of the ambient cues hang out, more noticeable in comparison. It wasn't retrieving any more detail, its just that those details were given something of a spotlight. When I played tracks with deep and/or heavy bass, there was no question that the X12 had better control. It now even had superior sub-bass, which it lacked earlier in the breakin process. The X12 has a richer midrange, which gives vocalists more chest register and to my ears that sounds more natural. I am anxious to do this same comparison with the HE-560. From what I have been reading, it is less midrange dominant than the 400i, has more linear bass and a wider stage. If this is true, it should match perfectly with the X12 and I may like this combination much better than the Aune S16 with the 400i.
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This is all that I have posted so far and please be mindful that these impressions are definitely system and breakin dependent. When I re-read the above, it appears that I am really favoring the X12, so I should clarify a bit. I have a subconscious preference for the X12 because I already own and love the H10. In my setup, where space is at a premium, the ability to make a pretty stack of the H10 and X12 was appealing to me. So, I was hoping from the get go that the X12 would at least equal the S16's performance. If I were to take this with my own grain of salt and try to honestly remove my Stuart colored glasses, I would have to say that these two DACs have different flavors that may appeal to different people based on thier taste and certainly their associated equipment. IMHO, the Aune S16 wins in the area of natural soundstage and elegant treble. The X12 wins in bass control and extension, midrange body and overall dynamics.