Pros: Clean, honest, detailed, natural sound; compact size; design and build quality; ease of use
Cons: None I could find; I don't own one
Have you ever seen one of those videos on Facebook where they show a deaf kid or baby with a new cochlear implant who hears sound for the first time? I've seen a few of them, and the script is always the same:
Faffing around getting things hooked up, checking everything is in working order. Baby or kid looks nonchalant, or uncomfortable with all the activity and attention and wires and stuff.
Sound is turned on. Doctor and parent(s) look on expectantly. Little person looks confused, perplexed, uncertain of what's happening as this new sensation registers.
Something clicks that what is happening is a good thing… a very good thing. Smile gradually takes hold, first with a mild upturn at the edges of the lips, and then taking over the whole mouth, eyes, face, until joy radiates in unfettered abundance.
Fade out… feeling warm and fuzzy… The End.
Something like this scenario happened to me this weekend. Well, steps 1-3 anyway; there was no fade out. Was I deaf and did I get a cochlear implant? No… nothing like that, but I did get to experience the X1S DAC/Amp from Aune Audio, and I was left with a grin from ear to ear. Okay, the experience wasn't as extreme as hearing for the first time, but I will say I was blown away by the sonic performance of this rather small, inexpensive piece of desktop audio gear.
Now I've had several days to enjoy the X1S, I'm still very impressed with the sound it pumps out, and how well it plays with every headphone and IEM I've thrown at it. And that leads us to this review.
Disclaimer: I applied for and was selected by Aune to be part of their worldwide review tour. Five reviewers will receive a free X1S, but it is unclear at the time of writing whether this will be decided based on review quality (however that might be perceived) or as a random draw; that said, I pride myself on honesty, and would not write a positive review in the hopes of receiving an item I didn't like at no charge.
Before getting into the review, a little about me. I'm 50 verging on 51, and so probably have deficiencies in my hearing (in a recent, entirely non-scientific test I discovered I can't really hear anything over about 15 kHz, with roll-of starting around 12 or 13 kHz, which I guess is pretty good for someone of my vintage but not perfect). I've been a music lover for decades, but am still relatively new to the MidFi/HiFi/Head-Fi game; I haven't listened to a lot of high-end equipment (yet), and am not an expert on the technical aspects of electronics or musical terminology. I have read a lot of reviews and threads on Head-Fi, and spend a lot of time on the site; as such I know what has been helpful to me in reviews and endeavor to provide what I consider useful insights to help others make decisions about items they are thinking about trying or buying.
I listen to a variety of music genres, in particular, Classical (mostly mid 1700s to mid/late 1800s), Jazz ('50s to 70's), Rock and some Prog-Rock ('70s), '80s New Wave/Electro, and Trip Hop/Acid Jazz (90's into 00's). My preferred sound signature would be characterized by a good sub-bass presence, tight mid bass, and relatively linear, detailed mids and highs. I like my music quite lush and rich, but with a good level of detail. I'm not a bass-head, am not a big fan of anything too boomy, and don't like highs that are too intense or harsh.
I have limited experience with desktop audio equipment, having only recently purchased my first desktop DAC/Amp (the Audio-GD NFB-15). In addition I have had a brief time with a couple of DACs from Yulong and Matrix. The bulk of my headphone music listening has been with portable equipment, and I certainly don't consider myself in any way expert in DAC performance or the various DAC chips currently available.
About the X1S
The X1S is an attractive and relatively small piece of equipment. It comes in black or silver, and I received a black unit for review. Build quality is solid and to high tolerances; everything fits together very well, there are no unsightly gaps or mismatched joints or edges, and no give or rattle to control elements.
The front of the unit is simply laid out, with input selector (for USB, optical, coaxial or line) on the left, 6.5mm headphone jack in the centre, and volume pot on the right. The input selector button is firm, with no looseness. The selector doubles as a filter switch, with long touches switching modes between fast roll-off, slow roll-off and minimum phase filter modes. I used the fast roll-off setting throughout my listening tests. The volume pot is large and moves smoothly, offering good resistance but still easy to adjust.
The rear of the unit is relatively busy due to the X1S' small size. There are a lot of inputs and outputs to accommodate, but layout makes sense and is well labelled. From left to right one finds power input, RCA audio in (left and right), RCA audio out (left and right), RCA coaxial in and out, optical in, and USB in with power switch directly above.
The top of the unit is very slightly curved so not really suitable for stacking anything on, though with the X1S' small size, the unit is likely to be top of anything it might be stacked with. If using a portable DAP as source, curvature isn't a problem as it is only very slight. Sides are grooved in a modern make-over that pays homage to the shape of earlier "X" models but puts the X1S firmly in 2015 from a design standpoint.
Specifications (from PDF manual included with device):
USB: Supports 32BIT/384K DSD128
Coaxial and optical: Supports 24Bit/192K
Digital coaxial out: Supports 24Bit/192K
Output voltage (@ 0dB): 2.1 Vrms
Frequency response (from 20 Hz to 20 kHz): ±0.1dB
Dynamic range: 126dB
THD+N @ 1KHz: -110dB
IMD+N @ 19KHz & 20KHz: -110dB
Stereo crosstalk: -112dB
Headphone output: 300 ohm/80MW
Size of product: 145mm x 45mm x 190mm (including volume pot and rear RCA inputs)
Net Weight: 2kg
Components: X1s, Power adapter, Manual (on USB stick), USB cable, 6.5mm to 3.5mm headphone adapter
The Aune X1S Sound
Listening was performed with a variety of headphones, both over ear (R70x, K7XX, HD598, and MSR7) and IEM (Noble 6 and Heaven VII). For source during general listening I used my MacBook Air with iTunes via USB. Comparisons were done with the Audio-GD NFB-15 and Yulong D200, using Aune S18 Digital Transport via optical as source. All music files were Redbook quality ALAC, ripped from CDs.
alt-J – Ms (from An Awesome Wave) for male vocals and instrumental balance.
Al Di Meola – Mediterranean Sundance (from Elegant Gypsy) for soundstage and detail.
Albeniz – Iberia (Alicia De Larrocha) for detail.
Cannonball Adderley – One For Daddy-O (from Somethin' Else) for comparisons with D200.
Dire Straits – Communiqué (from Communiqué) for mids and highs.
Dvo?ák – Symphony No. 9 "From The New World" (Carlo Maria Giulini, Philharmonia Orchestra) for detail and soundstage.
Massive Attack – Weather Storm (from Protection) for sub-bass.
Pearl Jam – Jeremy (from Ten) for detail and balance, and vocals.
Sade - Bullet Proof Soul (from Love Deluxe) for sub-bass and female vocals.
Simply Red – Sad Old Red (from Picture Book) for vocals, and mids and highs.
Steve Winwood – Spanish Dancer (from Arc Of A Diver) for detail.
Steely Dan – Hey Nineteen (from Gaucho) for comparison with NFB-15.
Other tracks also used, though not referred to in the review.
Bass: Bass goes low and has good crunch to it, with satisfying, visceral quality, and sub-bass felt in the pit of the stomach. Speed and transients are delivered honestly, with quick attack and natural decay.
Mids and Highs: Clarity and detail are the name of the game. Piano, sax, guitar and toms sound clean and realistic, both in their lower and upper registers. High hats and cymbals have good shimmer to them. Transients are quick, clear and lively. Definition and articulation in middle and upper registers is excellent.
Vocals: Male and female vocals are gorgeous. They are neither dominated by nor dominating of instruments and other musical elements. Voices are clear, pure and true to the recording, and sibilance is curtailed. Sade, Norah Jones, Beth Hart, Stevie Nicks, Mick Hucknall, Eddie Vedder, Mark Knopfler… whoever the singer, whether vocally textured, smooth, rough or clear, they sound natural and real, like who they are.
Sonic Balance: With every track and every headphone, balance was natural and realistic. There were very few points where I felt any instrument or frequency was over-emphasized or subdued, and I'd venture those times were due not to the X1S but to the nature of the headphone used. If it's in the track and the headphone is capable of playing it, you'll hear it.
Detail: To me this is an area where the X1S excels. Each sound is delivered cleanly and clearly, with great texture. Solo guitars and solo piano are delivered with clear realism and a strong sense of sting contact and vibration. Complex pieces – rock, jazz and classical – come through cleanly and clearly, with sparkle on high and thump down low.
Soundstage and Imaging: Sense of space and air is impressive, with X1S pushing headphones to their limits with all genres of music. With classical, in quiet passages the vastness of the hall and distance of the players can be felt, with a sense of blackness and emptiness pierced intimately by the instruments. In louder, more energetic passages, intimacy is replaced with dynamic energy; the players are no longer distant, but space – depth, width and height – remains. Instrument position is accurate, both left-right and front-back.
Hiss: The X1S is dark. No hiss at all with any of the cans or IEMs I tried. Just a vacuum of deep-space silence.
Since I have a couple of other desktop DACs on hand, I decided to pit them against each other. I find comparisons help me pick out finer details of sound delivery as differences are easier to discern then sonic nuances in absolute terms.
X1S vs. NFB-15: The X1S has no gain, so what you get on the volume pot is what you get on the volume pot. Even though only rated at 300 Ohms, X1S drives the R70x (470 Ohm) emphatically and robustly at around half-past-one on the pot (just over half volume; pot zeroes at 8 o'clock and reaches max at 6 o'clock). For equivalent volume, NFB-15 on High Gain is at 10 o'clock on a pot that goes from 6 o'clock to about four-thirty. Both seem to have ample power to drive more power-hungry cans. Both units sound excellent, and very close in sound signature, with natural, realistic presentation. X1S is slightly leaner and cleaner, and NFB-15 fuller. NFB bass is slightly rounder and smoother, and mids very slightly more strident and forward, with a harder attacking edge. Overall X1S is more laid back and NFB more dynamic, but the difference is minimal and only really evident after repeated switching back-and-forth.
X1S vs. D200: Similar to the NFB-15, I found the D200 just a bit fuller and more dynamic, and X1S leaner and cleaner. Differences were subtle.
The X1S is an attractive, sleek little box that carries a big punch. It's easy to use, with almost no learning curve at all. I was very impressed with its sound quality and sound stage. I don't have a lot of desk room so space-saving is key, and I'd love to pair it with the X5 Mk. II DSD Player for a beautiful desktop set-up with small footprint.
I found sound output dependent on cans or IEMs used, in that the X1S drives headphones to their full potential without adding colour or falling short sonically; if it's in the music and the headphone is capable of producing it, the X1S will bring the sounds out.
At a retail price of around US$290, I think the X1S is a steal, and well worth considering if you're looking for a design-conscious, compact DAC/Amp that delivers clean, clear, detailed, natural sound together with great soundstage. I'm certainly very tempted to purchase one myself!