Before moving on with the rest of my review, I would like to thank FiiO for providing me with a review sample of the FH7S in exchange for my opinions.

(Please forgive the lack of pictures here – I may put some later when I have more time.)

Intro

The FH7S is a 1 DD 4 BA per ear IEM, priced at $400 MSRP. What’s notable is that it uses the same dynamic driver as the FH9, and according to FiiO the FH7S is designed to channel the essence of the FH9 into a package with fewer drivers.

What’s included



I won’t bore with you with text here, the video above shows you what’s exactly in the box. Suffice to say there’s plenty of accessories to make your life with the FH7S easy. The only omission perhaps is a lack of 2.5mm balanced tip for the cable, but this may not matter much as more and more devices are adopting 4.4mm balanced.

Comfort, Ergonomics, and Build Quality

Build quality is excellent – both the IEM and the cable itself. Both feel solid and well finished (not cheap). It is very easy to change out the heads on the cable.

It is quite comfortable despite its large size. The metal finish is cool and comfortable to the touch and FH7S is curved to better fit your ear. However, the size is almost at the limit of what I would consider comfortable, and pairing it with larger eartips like the foam ones included does make it a bit uncomfortable.

Its semi-open nature means that it doesn’t isolate as well, and is more susceptible to its perceived frequency response being affected by environmental noise (usually bass). It still isolates to a certain extent, but definitely not as good as the typical closed IEM. (Like the FLC8S.)

The filters are really tiny and easy to lose, and are also not the easiest to change out. This is due to its tiny size and lack of grippable area to hold on to when unscrewing tips to change them. Perhaps a system like the ridged edges of the FLC8S filters (and with the entire filter itself being color-coded for easy identification) would make it easier to change filters.

One note about tips – there are plenty of tips included that do make an audible sound difference to choose from. Personally, I ended up using the new HS18 eartips not only because they sounded the best to me (more on that in the sound section), but also because they were the most comfortable. Being very thin meant they disappeared in your ears comfort-wise. However, because they are so thin you have to be careful how you put them in your ears – in my experience, their thinness means they more easily fold up on itself which means lack of seal.

Sound

Listening sources – most of my listening was done on the FiiO Q5 and X7 Mk2 with AM3B and AM3D amp modules. I also did some listening on an Xperia 1 II smartphone and on desktop setups (Teac UD-505 DAC/amp combo; and NuForce UDH-100 DAC paired with Monoprice-Cavalli Liquid Gold X).

Bass – This is the star of the show. The bass dynamic driver is not only very quick and controlled, but very dynamic and really slams (lots of weight and impact to it). It’s really capable of showing texture in bass notes. No matter which tips and filters you use, remarkably the bass never overshadows the mids (but it’s just right at the limit of doing so). There is maybe a slight mid-bass emphasis but sub-bass still comes through very powerfully.

Mids – If you get it in the sweet spot, vocals are actually very detailed and smooth, and with decent weight behind them. However, mids are tuned right at the limit of not being sibilant. Depending on your source, music, filters, and eartips, they may be a bit too much – but just a bit too much, mids are never really harsh.

Treble – This is actually a touch reserved. Treble is never really dark, but it is there and never calls too much attention to itself. Not to say that the treble is bad, it’s good because it works with good detail and it is not piercing.

Soundstage – Very wide and very deep – definitely a highlight of the FH7S. Depth especially is noticeably better than most IEMs I’ve heard before. Sounds are also separated very well and are precisely placed within the stage – both horizontal-wise and depth-wise.

Speed – Overall, the FH7S is no slouch in the speed department. I already mentioned the bass dynamic driver’s speed before, but the mid and treble BAs can keep up pretty well with even the most complicated orchestral music.

Dynamics – Pretty decent dynamics. I’ve already mentioned how the bass dynamic driver has great dynamics drivers, but overall the FH7S does very well in illuminating volume swings in your music – making stuff like classical and orchestral feel suitably epic. Music doesn’t definitely sound unnecessarily flat with the FH7S.

Sound signature

As I alluded to before, the FH7S has an overall fun sound signature where the bass and the mids are cranked up right to the max before they start interfering with each other and the other parts of the frequency spectrum – this is definitely not a neutral IEM. There is a bass and mid emphasis no matter which set of eartips or filters you use, but the FH7S sound signature can change quite a bit from rolling those two elements.

Eartips – My favorites were the HS18 tips, followed closely by the SpinFit tips. To me, both of these had a similar sound signature (a bit more present but relatively more well-controlled bass and present mids and trebles), but the HS18 edged out the SpinFit tips for me due to its slightly smoother mids and vocals. The pre-installed “balanced eartips” had a bit less-controlled bass and a bit too much mids for me.

Filters –

Red - While the red filters are advertised as “bass” filters, I’m not sure if I would label the FH7S as a basshead IEM in that configuration. The sound signature with this filter is more like a warm sound but with a bass emphasis. I say this because the mids and treble are noticeably brought down compared to the other filters, but the bass also loses a bit of its slam and explosiveness in this configuration. Not my preferred configuration, but it does show how much the sound signature of the FH7S can change with the provided accessories.

White – Mids and highs are noticeably more present – and sound more correct to me than under the red filter. Mids can start to be a bit overbearing depending on the track, but most of the time this is not a problem. Bass also seems more explosive and “effortless” under this filter. However, while the bass still doesn’t overshadow mids and vocals, this is definitely still a more “fun” sound signature and not neutral reference. I listened to this configuration the most.

Green – basically like White, but with noticeably more mids and treble so that bass takes more of a backseat. But this configuration just gives more of the mids and treble, not that they are any harsher. However, depending on the track the bass is still surprisingly present. The green filter gets closer to a neutral sound signature but I still wouldn’t call it that because the bass can sometimes come back with a vengeance.

Source scaling – While the FH7S sounds good out of most sources, it does notably come more alive with better sources. There was a noticeable jump in detail, dynamics, and bass control when I switched from listening to the FH7S out of my smartphone to the Q5 and X7 Mk2. Just for fun, I decided to plug in the FH7S into desktop equipment and was pleasantly surprised – detail seemed to get even better and bass also notably became more dynamic yet more well-controlled at the same time. Just beware that the FH7S is sensitive enough that it can pick up noise if your amp isn’t the cleanest. (This was only a problem with some of the noisier outputs of my desktop setups.) Soundstage wise this doesn’t really scale with the source, as you’re already getting most of its imaging and layering prowess even with the lowliest source.

Conclusion

The FH7S is a carefully-tuned fun-sounding IEM that’s well rounded – as long as you’re not expecting strict neutrality and you’re ok with slightly elevated mids. It’s comfortable, built well, comes with lots of accessories, and sounds great (musically and technically). Recommended.

So I'm going to try out a new review format - something that is much shorter than my earlier reviews and hopefully easier to read. Hope this gives people a better idea of what to expect from the M3K!

Just to be clear – I was given a M3K review unit to check out (not keep) in exchange for a brief review.

With all that out of the way, let's dive into the review.

Design, ergonomics and build quality
The M3K’s tiny size fits nicely into your hand, not being too tall or wide. The body is made of a nicely finished aluminum alloy with rounded (not sharp) corners, giving the player a much more premium feel than its price would suggest. It’s also not too slippery in the hand, but there is a silicone case included if you are concerned about that. The silicone case isn't anything special though, but it doesn't smell!

The capacitive buttons work well - they were quick and responsive, and their backlit nature makes a world of difference when trying to use the player in dark environments. The buttons aren't too dim or bright either.

Screen
This probably has one of the best screens I’ve seen from FiiO yet. The vivid IPS screen has decent viewing angles as well as nice colors and contrast. Also, it actually gets bright enough to use in moderate to strong sunlight – just don’t use it in extremely sunny conditions like on a hot day in Southern California.

UI and Fluidity
First impressions are positive when you boot up the M3K. The M3K boots up quickly, and navigating through the menus with the vertical touchpad is easy and intuitive. However, after a while I started to notice that the M3K puts priority on some operations over others, probably due to the X1000E processor’s limitations. For example, when selecting/moving onto a new track, the M3K starts playing the new song pretty quickly but there’s a pretty obvious delay in switching the album art. This is not necessarily a bad thing, and I’m not sure if most people will care enough about it.

Also, there currently is no good way to scroll through your music if you have tons of tracks. You either use the scroll wheel or use the skip forward/back buttons to do so, but either way takes a while to go through your music, and FiiO hasn't implemented any other quicker methods.

Recording
This could have been a more useful feature, but sadly I think Fiio may need to work on this more. Right now, the recording volume is simply too low – I literally have to crank the volume to near max to hear recordings of people talking at normal volumes. And I’m not sure if its just me, but when you crank the volume up that high, there seems to be some kind of high-pitched whine on the recordings.

USB DAC
It works well enough on both Mac and PC, with no noticeable bugs that I could catch.

Battery life
What Fiio advertises is true, the battery life is pretty long. I was basically hitting their advertised battery life for playing music. While I haven’t really had the chance to test their 38 day standby claim, I will say that I accidentally left it on for a week once (paused, not playing music) and the battery meter didn’t even go down 1 bar.

Sound
I think this is a mixed bag. Overall, the M3K has what I would call a neutral sound signature, maybe slightly leaning towards being bright. Basically, it has treble that’s very much present but somewhat grainy, while bass is good for the price point.

On the one hand, the M3K is obviously improved in sound over its predecessor the M3, especially in bass, soundstage size (deeper and wider) and imaging (clearer placement of instruments in the song). On the other hand, I thought the Fiio X1 (only $20 more) mostly sounded noticeably better than the M3K – it just sounds smoother yet with more details revealed and plus, the X1 has enough power to drive over-the-ear headphones in a pinch, which the M3K can’t really do.

To go into more detail – compared to the M3, the M3K has a wider and deeper soundstage as well as better imaging, mainly because it has a noticeably blacker (quiet) background compared to the older player. The M3K also seems to bring more of the sub-bass out and sounds more dynamic compared to the M3, and has noticeably more power (the M3K drove my ER4 noticeably better than the M3 did). However, the M3K’s mids and treble seem to be as grainy as the M3’s.

Compared to the X1, the M3K is mostly inferior in terms of sound. The one thing that the M3K does better than the X1 is that it sounds more dynamic – the X1 seems to be more “flat” in terms of capturing volume differences within the track. Soundstage size and imaging seem to be equal between the M3K and X1. However, the M3K sounds noticeably more grainy compared to the X1, while providing less details – and to me, this was not a minor difference. Also, bass quality is definitely a step up on the X1. The X1 also drove my higher impedance IEMs (100-ohm ER4) and more sensitive over-the-ear headphones (like Sennheiser HD598) better.

Overall
The M3K is a decently valued player if you are looking for something with decent sound quality, great battery life, and good ergonomics in a very portable package. Just don’t expect to really use the recording function.

However, for more discerning audiophiles who want just a basic player, if they are willing to spend just $20 more (at the time of writing, M3K is $70 vs X1 at $90 on Amazon) I would steer them towards the Fiio X1, which to me provides much improved sound quality - enough to outweigh the X1 being noticeably slower in usage (though it isn't what I would call unusable). With the X1, you don’t really give up many functions (and you get Bluetooth on it), and while battery life is noticeably less than the M3K, I think for many people 10 hours is enough.

Introduction
Tl;dr: FiiO sent me a review unit for my honest opinion, and a bit of background about myself.


I tend to like a neutral sound signature, perhaps with a bit of warmth. But if one were to ask me to pick between a very warm or a very bright sound signature, I’d go towards the brighter one. I like a large variety of music including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.

Before I begin with the rest of the review, I would like to say that I paired the FiiO F5 with the FiiO X5 3rd gen and the Questyle QP1R in the making of this review.

I would like to thank FiiO for letting me check out their new F5 IEM in exchange for my honest opinion!

Specs
Before we go onto the rest of the review, a specifications table might be useful.


Packaging and Accessories
Tl;dr: FiiO gives you a decent amount of accessories – including a hard carrying case and even a 2.5mm balanced cable.

If you’ve seen FiiO’s recent designs for other boxes (such as the X5iii and the X7), you’ll know what to expect here. The F5 comes in a box very similar to those players, with another box on the inside that you can take the lid off of. It’s packaged quite nicely actually, especially for its price point.


Inside the box you’ll find a generous amount of accessories. When you first look in the provided hard carrying case, you’ll discover the F5 IEMs themselves and six pairs of ear tips. There are two kinds of ear tips – one set which I will call the “black-cores”, and the other set which I’ll call the “color-cores”. The black-core tips have a squishy, soft core while the color-cores have a much harder core. Small, medium, and large sized tips for each set are provided. As we’ll go into later, these different sets of eartips do provide different sound signatures.


The F5 also comes with two cables – one is 3.5mm TRRS cable that also contains in-line controls with a microphone on it – pretty handy for usage with a smartphone. The other is a 2.5mm balanced cable purely for audio – very nice, and this is especially great of FiiO to do so for the price point they are targeting with this headphone.

Quick note on the quality of the microphone on the 3.5mm cable – it’s good quality. I tried using it in phone calls, and pretty much everybody I had a phone call with said the mic sounded clear, and easily picked up my voice. So the in-line controls are very much a worthwhile part of the F5 package.

Overall, FiiO seems to provide you with a good amount of accessories for the F5 – definitely a plus in my book.

Build Quality, Design, and Comfort
Tl;dr: Excellent comfort, well-designed cables. The F5 also seems to work with a bunch of different tips.

First off, while the build quality and design of the actual F5 IEMs won’t set anybody’s world on fire, it’s actually quite good for its price range. The F5’s shell is made up of plastic that doesn’t feel too cheap and doesn’t feel too fragile. I’ve actually squeezed the F5 pretty hard in trying to get some of the ear tips on (more on that later) and the IEM is still good as new.

Moving onto the cables, they’re good quality. Not excellent, but pretty good. Both the 3.5mm and 2.5mm cables use MMCX connectors that snapped into the F5’s body easily and securely. I like how both the 3.5mm and 2.5mm cables aren’t prone to tangling, seem reasonably tough (I haven’t subject them to that kind of abuse) and don’t provide too much microphonics when moving around with them. Also, the actual in-line controls on the 3.5mm cable are well-designed. The buttons there are quite tactile, and I especially like how the play/answer call button is recessed enough so that one can distinguish it from the other buttons quite easily just by touch.


As for comfort – FiiO’s marketing materials aren’t lying, this is a seriously comfortable IEM that I could wear for hours. The angled design of the body (somewhat like the FiiO EX1) allows the F5 to not sit in my ear too deeply yet still manage a good seal. This is very much a relief compared to the deep insertion of my Etymotic ER4PT that I normally use.

As for the comfort of the tips, they’re just like any other decent silicon tips – they’re comfortable and allow you to get a decent seal easily. While the medium-sized black-core and color-core tips both fit my ears the best, I actually found the small-sized tips to fit well in my ears too. As for what tips you can use, any of the tips that fit on my Hifiman RE-00 also worked for the F5 too. Also, while I didn’t specifically try it out, I suspect that any tips that work with the FLC8S also will work the F5 since I’m actually using RE-00 tips on my FLC8S.

About the passive noise canceling the F5 provides – it’s decent, though it’s not excellent. Let’s not even compare this to my ER4, the F5 doesn’t cancel out noise nearly as well my FLC8S – probably due to the somewhat shallow insertion of the F5. With the right-sized ear tips, the F5 does cancel out noise somewhat better than the EX1 though.

Remember how I talked about squeezing the F5 pretty hard to get some of the tips on? Specifically, I somewhat had trouble putting on the color-core tips, whose hard core really makes it somewhat hard to squeeze it into a shape so I can get the tip around the nozzle of the F5 IEM.

FiiO really seems to have nailed it in the comfort and design aspects. I don’t really have much to complain about.

Sound Quality
Tl;dr: The F5 features a tastefully done darker sound signature with notably good bass. Compared to the EX1, it’s hard to say which is better and this will come down to preference.


Now onto the most important part. How does it sound?

Overall, the F5 presents a warmer, darker, smoother sound signature. With a good seal, bass is very much elevated above neutral, with a slight mid-to-upper bass emphasis but sub-bass is still very strong. I’m tempted to say that it’s somewhat encroaching on bass head territory. And despite this rather heavy bass presence, it doesn’t actually get in the way of the mids most of the time.

Bass quality is very good on the F5 – even though there’s a lot of it, I never felt that it was out of control. I also felt that the bass was very punchy, quite detailed and textured.

Mids are also somewhat forward on the F5, with the treble being rather shelved. And while the treble is definitely not as prominent as I prefer, I do think it is still pretty detailed for the price. Both the mids and treble on the F5 are smooth.

Dynamics on the F5 are quite good. Explosive passages where the music gets quite loud all of a sudden are rendered with gusto on the F5, especially with that bass slam I mentioned earlier.

The F5 also boasts some pretty good separation in a moderately wide-and-deep soundstage for an IEM. Imaging and layering/depth perception were decent, so I was relatively easily able to tell where the sounds were coming from within the music. I really have no big complaints here.

Remember I mentioned earlier about the different sets of ear tips having different sounds? The black-core tips to my ears give slightly more elevated bass (both mid and sub-bass seemed to be equally elevated) while the color-cores give you slightly less bass. Both the mids and treble seemed to be presented in about the same manner using either set of tips.

However, one thing that I found nifty about the F5 was that I could put on the small-sized color-core ear tips (one size smaller than the medium-sized tips which give me a perfect seal) and get a much more neutral sound signature. No, it does not turn the F5 into something like the ER4 with this change, but it did bring the bass significantly down without totally making it disappear. In fact, the bass even with less of a seal was definitely still prominent, and the mids and highs were relatively unaffected. This results in a sound signature kind of a like a slightly warmer Sennheiser HD650, and was my preferred way to listen.

I thought it was pretty cool for the F5 to pull off two main different sound signatures like that depending on the tips you use. And of course, the different sets of included ear tips also allow you to slightly further tune the F5 to your preferred sound. However, no matter what tips or seals I tried, I could not get more treble out of the F5 – it simply wasn’t tuned to be that way.

Honestly, the F5 presents a darker and smooth sound signature that is executed in a manner above what you would normally expect for something in its price range. So while the F5 is not my preferred sound signature, I still think its overall sound quality should actually be commended, especially for its price.

Comparison with FiiO EX1 (first generation)


Something that people might be interested in is how the F5 compares with the FiiO EX1, since the EX1 (and now the EX1 2nd gen) was originally the IEM offered by FiiO at the price point that the F5 is slated to go for. So I managed to borrow a first-gen EX1 (sorry, I couldn’t get my hands on the 2nd gen version) to be able to compare it to the F5.

Overall, I would say that the two are comparable in quality but offer very different sound signatures. I felt that width and depth of the soundstage, as well as the separation, imaging, and layering abilities of the two IEMs were very similar. Overall detail level between the two IEMs is also very similar too – I couldn’t reliably say which IEMs gave me clearer picture of the tiniest details in the music.

However, with a good seal the F5 offers much more bass than the EX1. If you purposely get less of a seal by using smaller-than-usual eartips with the F5, then the bass level decreases to slightly less than that of the EX1. No matter what kind of seal you use with the F5, however, I simply feel that the F5 had a more pleasing bass with better punch and slam. I would probably also say that the F5 had slightly more detailed bass too.

Mids on the EX1 are a bit recessed compared to those on the F5. The upper-mids also seem to be more prominent on the EX1 – at times, this was a bit too much and didn’t sound that realistic to me, while the F5 handled these frequencies better. However, I do like that the EX1 had more prominent treble. But it’s hard to say whether the F5 or the EX1 is actually better. At times, I preferred the EX1’s increased treble presence, while in others I preferred the F5’s bass punch and less wonkiness in the upper-mid range. Overall, for most people I think it’s going to come down to preferences and what type of music you listen to when deciding which IEM is better.

Conclusion
Tl;dr: If you’re looking for a multi-purpose IEM with a darker sound under $100, you should strongly consider the F5.

I think it’s obvious in the rest of the review that I think pretty well of the F5, despite it offering a sound that I usually don’t prefer. First and foremost, its sound quality is an obvious strength of the F5, with bass that I think is excellent especially for the price. Combine that sound quality with excellent comfort, somewhat tunable sound, and truly useful included accessories (with microphone and balanced cables) and I think you have a winner in the under $100 IEM category. Honestly, for this entire package FiiO could have priced it at over $100 and I still think it wouldn’t be overpriced. At its current price of $64.99, it’s a fantastic deal considering the whole package you are getting.


Thanks for reading my (somewhat) long review of the FiiO F5!

Table of Contents

• Introduction
• Specs
• Build Quality
• Battery Life
• Sound quality
  • Volume-matched Comparisons with other amp modules
• Conclusion

 
(Before I even begin with the introduction, I wanted to say that the above table of contents is for your convenience. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself.
 
 
This review is specifically about the AM3 amp module designed for the FiiO X7 DAP. For a review of that particular player, you may want to click here for my review or take a look at the many other reviews of the X7.
 
 
I would like to thank FiiO for letting me demo all of the X7 amp modules in exchange for my honest opinion!
 
 
 
Specs
 
Before we go onto the rest of the review, a specifications table might be useful.
 
 
Build Quality
 
Tl;dr: Great build quality. That the color doesn’t exactly match the rest of the X7 is probably the only con.
 
The AM3 amp module, even this prototype that I am evaluating, exhibits some great build quality like the rest of the X7. Despite not being a production unit, the metal feels smooth and polished, with no rough edges. AM3 also snaps in easily, where it is flush, tight and secure to the rest of the X7’s body once you put in some screws.
 
It pretty much looks like it belongs with the rest of the player, if it weren’t for the fact that it’s a much darker shade of grey compared to the rest of the X7’s brighter silver color, like with AM2 and AM5. Honestly, this isn’t such a big deal for me since I’m not looking at the player for much of the time. There’s also the fact that you won’t notice this at all if you buy a cover for the X7.
 
Not much for me to complain about here, even at this prototype stage.
 
 
 
Battery Life
 
Tl;dr: You take a pretty substantial hit to battery life compared to AM1, but that’s the price of a powerful balanced amp and it’s no worse than the AM5.
 
Unfortunately, more power on tap means that the battery life will inevitably suffer. In AM3’s case, the hit to battery life is notable.
 
For single-ended mode, I conducted my battery life testing under the following conditions: the X7 powering the Etymotic ER4S at low gain at a volume level of 39, using the FiiO Music app in Android mode, and with the screen, pulsar light, Wi-Fi, and Bluetooth off. The music the X7 cycled through was mixture of CD-quality and high-res FLAC, as well as some DSD tracks. CD-quality FLAC tracks made up the vast majority of the music.
 
Under those constraints, as seen in the screenshot below I managed to get about 7 hours and 14 minutes of playtime. In comparison, with the AM1 amp module volume-matched and under the same conditions, I got 8 hours and 22 minutes of playtime. With the AM2 amp module under the same conditions and volume-matched, the X7 could play for 7 hours and 41 minutes. With AM5 powering the same headphones volume-matched and playing under the same conditions, the X7 could squeeze out 6 hours and 30 minutes out of its battery.
 
 
 
But wait, what about battery life under balanced mode, you might ask? Well, for that, since I don’t have any IEMs with balanced cables, I tested how long the battery could last using my Hifiman HE-400i headphones, which I do have terminated in balanced. Otherwise, the conditions remained the same as explained above. I also did a battery life test with the same headphone in SE, volume-matched and also under the same conditions, to examine the effect of balanced on battery life.
 
As seen below on the left screenshot, under SE on the 400i I got around 6 hours and 27 minutes of play time. With balanced mode on the same headphone as seen on the right screenshot below, I got around 6 hours and 56 minutes of play time. While such a difference may be surprising, I attribute this to the fact that I used shuffle mode when conducting battery life tests. Perhaps with SE, the X7 just happened to queue up more high-res PCM and DSD tracks, leading to the lower battery life seen here. I would expect that there really is no difference in battery life between SE and balanced out, like FiiO themselves have claimed.
 
 
Ultimately, you’re going to take a hit to play time compared to AM1 if you use the AM3 even in SE mode. However, given AM3’s better sound quality over AM1 and AM3’s balanced mode (as we will see in the next section), AM3’s battery life doesn’t seem that bad in comparison to the other amp modules. But it doesn’t change the fact that you won’t be playing music for very long under battery power with the AM3.
 
Last thing I want to stress – the AM3 unit I am using is a prototype. Thus, you can’t exactly take these battery life numbers as final, though they do match up with what FiiO claims.
 
Sound Quality
 
Tl;dr: AM3 balanced clearly sounds better than SE mode. While AM3 SE does well with IEMs, it struggles with full-sized headphones. But AM3 balanced probably does the best with full-sized headphones out of any X7 amp module. IMO, AM3 SE sounds better than AM1.
 
Headphones primarily tested with: FiiO EX1/Dunu Titan 1 (SE only), Etymotic ER4S (SE only), Hifiman HE-400i (SE and balanced), and Sennheiser HD700 (SE and balanced).
 
You’ve waited long enough by now. How does the thing sound?
 
Overall, the AM3 sounds neutral. It actually sounds very similar to the AM2 and AM5 in terms of a neutral overall sound signature, despite using very different chips.
 
AM3 presents lots of detail and has very good separation, even in SE mode. Soundstage is of moderate width (not the largest I’ve heard), but depth is very good. When all of this is combined with the rather good imaging and layering (depth perception), the AM3 presents a very coherent and convincing 3D soundstage.
 
Volume-Matched Comparisons
 
All comparisons here were conducted under volume-matching with a C-weighted SPL meter.
 
AM3 SE vs. AM3 Balanced
 
Balanced operation isn’t really going to be of much use if it doesn’t sound better than in SE implementation, right? Well, I’m glad to say that the AM3 in balanced mode clearly sounds better than when it is being run in SE.
 
For full-sized headphones at least, in balanced mode notes sound more airy and less constrained, and bass is better-controlled and deeper and more textured. The soundstage also gets slightly wider and deeper while separation gets noticeably better, which leads to better imaging and layering. There’s really no contest – AM3 balanced here just sounds better than AM3 SE.
 
Vs. AM1
 
The AM1 in comparison to the AM3 sounds “brighter” and a little more “metallic” and “brittle.” The AM3, in contrast, sounds somewhat “warmer” but also more natural in that notes are still as detailed without sounding like the detail is forced like AM1 can at times. AM3’s soundstage in SE is about the same width as AM1 but is slightly deeper, making for a more 3D soundstage in which it is easier to perceive depth and layering of notes. With AM3 balanced, the difference gets even bigger – the soundstage increases in width and depth yet again, making for an even more 3D soundstage. All of this can be noticed even when using easy-to-drive IEMs like the FiiO EX1 in SE mode.
 
AM1 also sounds a tiny bit underpowered in driving full-size headphones in comparison to AM3 SE. The difference here gets much larger with AM3 balanced. Not only do we get less grainy and strained notes, more-controlled and deeper and textured bass with AM3 balanced, but separation also seems to be somewhat better.
 
All in all, I definitely prefer the AM3 (even in SE mode) over the AM1 purely in terms of sound quality no matter what headphones are used. However, one has to consider the significant advantage in battery life the AM1 holds over the AM3.
 
Vs. AM2
 
First off, overall AM2 sounds very similar to AM3 in terms of soundstage size, detail retrieval, separation, imaging, etc. Perhaps AM3 is very slightly “sharper” and clearer sounding than AM2, but honestly I could just be imagining it.
 
As for AM3 SE vs. AM2, the AM2 is as capable as AM3 SE in powering IEMs (even more power-hungry ones). I honestly can’t tell much of a difference here.
 
However, for full-size headphones, AM2 actually comes out ahead. AM2, to me, simply produces less grainy notes and better-controlled and better-textured bass than AM3 SE when powering larger headphones.
 
But with AM3 balanced, the tables completely turn. (At least with full-size headphones, since I don’t have any balanced IEMs to test with.) Notes sound more airy and less constrained than on AM2. Bass is also deeper, more well-textured, and better-controlled. AM3 balanced’s soundstage is also slightly wider and deeper, and separation on AM3 bal. is also noticeably better (which also leads to better imaging and layering/depth perception).
 
So if you are planning to just use single-ended headphones, go with AM2 since it sounds just as good or better (depending on the headphone) with better battery life. But if you want to get the most out of your larger headphones, go with AM3 balanced.
 
Vs. AM5
 
First off, overall AM3 sounds very similar to AM5 in terms of soundstage size, detail retrieval, separation, imaging, etc. AM3 even sounds similar to AM5 in that they both seem to present notes that are a bit “sharper” than on AM2.
 
For IEM’s, you’d be hard pressed to tell any differences between AM5 and AM3 SE. However, for full-size headphones, AM5 as expected comes out ahead. AM5, to me, simply produces less grainy notes and better-controlled and better-textured bass than AM3 SE when powering larger headphones.
 
But what about AM5 vs. AM3 Balanced? Here, I actually prefer AM3 balanced by a bit. AM3 balanced presents a slightly wider soundstage with slightly airier notes (perhaps due to the blacker background given by balanced operation). Separation is noticeably better (more separated) on AM3 balanced than on AM5. This also means that imaging and especially layering are better on AM3 balanced than on AM5.
 
However, both AM5 and AM3 balanced powered my HE-400i and HD700 just as well as each other. I really couldn’t hear a difference in this respect.
 
Overall, I wouldn’t say you are missing out on much if you choose to take AM5 over AM3 in balanced mode. The real noticeable difference between the two is the better separation of AM3 balanced (which also leads to better layering, etc.) but otherwise they both sound as good as each other when powering larger headphones. Battery life is also similar between the two amp modules. To me there’s no doubt about it, AM3 balanced is the best. However, I would say go for AM3 if you have balanced headphones that you want to get the best out of, otherwise you will do just fine with AM5.
 
 
 
Conclusion
 
Tl;dr: The last sentence of this next paragraph.
 
At $99, the AM3 amp module is a good way to really bring out the best of your balanced headphones. In balanced mode, it sounds the best out of all of the other X7 amp modules and even has enough power for moderately power-hungry full-sized headphones. The only real major con with AM3 is that battery life takes a hit, though this is no surprise due to AM3’s capabilities. Overall, if you want to extract the best out of your headphones with the X7, look no further than the AM3 balanced module.
 
Thanks for reading my (somewhat) long review of the AM3 amp module!

Table of Contents

• Introduction
• Specs
• Build Quality
• Battery Life
• Sound quality
  • Volume-matched Comparisons with other amp modules
• Conclusion

 
(Before I even begin with the introduction, I wanted to say that the above table of contents is for your convenience. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself.
 
 
This review is specifically about the AM5 amp module designed for the FiiO X7 DAP. For a review of that particular player, you may want to click here for my review or take a look at the many other reviews of the X7.
 
I would like to thank FiiO for letting me demo all of the X7 amp modules in exchange for my honest opinion!
 
 
 
Specs
 
Before we go onto the rest of the review, it might be handy to have a specifications table on hand.
 
 
Build Quality
 
Tl;dr: Great build quality. Perhaps the only con is that the color doesn’t exactly match the rest of the X7.
 
The AM5 amp module, like the rest of the X7, exhibits some great build quality. The metal feels smooth and polished, with no rough edges. AM5 also snaps in easily, where it is flush, tight and secure to the rest of the X7’s body once you put in the included screws.
 
It pretty much looks like it belongs with the rest of the player, if it weren’t for the fact that it’s a much darker shade of grey compared to the rest of the X7’s brighter silver color. Honestly, this isn’t such a big deal for me since I’m not looking at the player for much of the time. There’s also the fact that you won’t notice this at all if you buy a cover for the X7.
 
Not much for me to complain about here.
 
 
 
Battery Life
 
Tl;dr: You take a pretty substantial hit to battery life compared to AM1, but that’s the price of having that much power on tap.
 
Unfortunately, more power on tap means that the battery life will inevitably suffer. In AM5’s case, the hit to battery life is notable.
 
I conducted my battery life testing under the following conditions: the X7 powering the Etymotic ER4S at low gain at a volume level of 38, using the FiiO Music app in Android mode, and with the screen, pulsar light, Wi-Fi, and Bluetooth off. The music the X7 cycled through was mixture of CD-quality and high-res FLAC, as well as some DSD tracks. CD-quality FLAC tracks made up the vast majority of the music.
 
Under those constraints, as seen in the screenshot below I managed to get about 6 hours and 30 minutes of playtime. In comparison, with the AM1 amp module volume-matched and under the same conditions, I got 8 hours and 22 minutes of playtime. With the AM2 amp module under the same conditions and volume-matched, the X7 could play for 7 hours and 41 minutes. With AM3 SE powering the same headphones volume-matched and playing under the same conditions, the X7 could squeeze out 7 hours and 14 minutes out of its battery.
 
This is my major complaint with the AM5 – battery life on the X7, which was only acceptable to begin with on the AM1, now takes a pretty big hit. Hopefully you aren’t going anywhere without a charger for long (or even moderate) periods of time if you plan to pair up your X7/AM5 combo with your full-sized headphone.
 
However, at the same time, I also understand that FiiO really can’t do much about this situation, short of maybe adding an extra battery to the amp module which would probably add lots of challenges (as well as probably increasing the price). This is the price of trying to driving big headphones with a little player.
 
 
 
Sound Quality
 
Tl;dr: The AM5 does well with a wide variety of headphones, from IEMs (surprisingly) to many (but not all) full-size headphones. Better than AM1 and AM3 SE, and IMO slightly better than AM2, though the latter is debatable. However, I did end up liking AM3 balanced over AM5.
 
Headphones primarily tested with: FiiO EX1/Dunu Titan 1, Etymotic ER4S, Hifiman HE-400i, and Sennheiser HD700.
 
Now is probably the most important part. How does it sound?
 
Overall, I would say that the AM5 has a neutral tone. It’s not very slightly warm, as some may perceive with the AM2, nor is it slightly bright, as some may say with the AM1. Really, it’s in between those two.
 
AM5 sounds plenty detailed and has great separation. While the soundstage is only moderately large (but by no means small), it boasts pretty good depth. Altogether, this makes for a very 3D soundstage with good imaging and layering (it’s easy to pick out sounds in terms of left/right and near/far).
 
AM5 also has the finesse to drive IEMs despite having way more than enough power for them. I could not detect any hiss or noise when I paired the AM5 to the Etymotic ER4S and the FiiO EX1, even with the music paused and the volume cranked up to max on high gain. Combined with the low output impedance, the AM5 is actually well-suited for driving in-ear monitors.
 
AM5 also did well with full-sized headphones, as it was designed to do. It never made my Hifiman HE-400i and Sennheiser HD700 sound underpowered with strained notes or uncontrolled bass or with any of the tell-tale signs that a headphones is not receiving enough power.
 
Volume-Matched Comparisons
 
All comparisons here were conducted under volume-matching with a C-weighted SPL meter.
 
Vs. AM1
 
The AM1 in comparison to the AM5 sounds “brighter” and a little more “metallic” and “brittle.” The AM5, in contrast, sounds somewhat “warmer” but also more natural in that notes are still as detailed without sounding like the detail is forced like AM1 can at times. For example, cymbals come across more cleanly on AM5 than on AM1 because on the latter, cymbals are too strong. This also means that stuff like vocals are given more “depth” and nuance on AM5. AM5’s soundstage is about the same width as AM1 but is slightly deeper, making for a more 3D soundstage in which it is easier to perceive depth and layering of notes. All of this can be noticed even when using easy-to-drive IEMs like the FiiO EX1.
 
AM1 also sounds somewhat underpowered in driving full-size headphones in comparison to AM5. Not only do we get less grainy and strained notes, more-controlled and deeper and textured bass with AM5, but separation also seems to be somewhat better.
 
All in all, I definitely prefer the AM5 over the AM1 purely in terms of sound quality no matter what headphones are used. However, one has to consider the significant advantage in battery life the AM1 holds over the AM5 (in this case, perhaps the AM2 is better).
 
Vs. AM2
 
AM5 and AM2 for the most part sound very, very similar. However, notes seemed to be a bit clearer, perhaps sharpened up a bit (but not overdone) on AM5. This can, for example, make wind instruments seem a tiny bit airier and vocals a bit “breathier.” AM5 also perhaps has a slightly wider soundstage, but depth of the soundstage is comparable between the two. I must emphasize that all of these differences are not that big, and that the two sound very close to each other.
 
To be honest, there’s not much improvement (if at all) in going to AM5 over AM2 for IEMs, even for harder-to-drive ones such as the ER4S. However, there seems to be an audible, if not major, improvement in using AM5 over AM2 to drive full-size headphones – for the HD700 and HE-400i, I thought I heard on AM5 that notes were slightly less grainy, slightly more open-sounding, that there was slightly more hard-hitting bass, and with slightly more separation.
 
So AM5 or AM2? Honestly, I think the biggest difference between the two is really how much power each can provide, and so this really depends on what type of headphones you listen to. If you mostly listen to IEMs with perhaps the occasional moderately power-hungry full-size headphone, go for AM2 because it has better battery life. If you frequently listen to hard-to-drive full size headphones, go with AM5.
 
Vs. AM3
 
First off, overall AM5 sounds very similar to AM3 in terms of soundstage size, detail retrieval, separation, imaging, etc. AM3 even sounds similar to AM5 in that they both seem to present notes that are a bit “sharper” than on AM2.
 
For IEM’s, you’d be hard pressed to tell any differences between AM5 and AM3 SE. However, for full-size headphones, AM5 as expected comes out ahead. AM5, to me, simply produces less grainy notes and better-controlled and better-textured bass than AM3 SE when powering larger headphones.
 
But what about AM5 vs. AM3 Balanced? Here, I actually prefer AM3 balanced by a bit. AM3 balanced presents a slightly wider soundstage with slightly airier notes (perhaps due to the blacker background given by balanced operation). Separation is noticeably better (more separated) on AM3 balanced than on AM5. This also means that imaging and especially layering are better on AM3 balanced than on AM5.
 
However, both AM5 and AM3 balanced powered my HE-400i and HD700 just as well as each other. I really couldn’t hear a difference in this respect.
 
Overall, I wouldn’t say you are missing out on much if you choose to take AM5 over AM3 in balanced mode. The real noticeable difference between the two is the better separation of AM3 balanced (which also leads to better layering, etc.) but otherwise they both sound as good as each other when powering larger headphones. Battery life is also similar between the two amp modules. I would say go for AM3 if you have balanced headphones that you want to get the best out of, otherwise you will do just fine with AM5.
 
 
 
Conclusion
 
Tl;dr: The first and last sentence of the next paragraph.
 
The AM5, at only $99, is a relatively affordable way to really give your X7 the power it needs to drive a wide variety of headphones, as well as giving better sound quality than the included AM1 amp module. My only major complaint with the AM5 is the worse battery life, which is unfortunate but unavoidable due to physics. Perhaps more people would be better served by the AM2 if they don’t have so power-hungry headphones, due to its similar overall sound quality but with better battery life. And there’s also the AM3 balanced module, which IMO is the best for full-sized headphones but obviously requires investment in balanced cables. Overall, get the AM5 if you want something that can really drive larger headphones well but without having to spend more to get into a balanced setup.
 
Thanks for reading my (somewhat) long review of the AM5 amp module!

Table of Contents

• Introduction
• Specs
• Build Quality
• Battery Life
• Sound quality
  • Volume-matched Comparisons with other amp modules
• Conclusion

 
(Before I even begin with the introduction, I wanted to say that the above table of contents is for your convenience. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself.
 
 
This review is specifically about the AM2 amp module designed for the FiiO X7 DAP. For a review of that particular player, you may want to click here for my review or take a look at the many other reviews of the X7.
 
I would like to thank FiiO for letting me demo all of the X7 amp modules in exchange for my honest opinion!
 
 
 
Specs
 
Before we go onto the rest of the review, let’s post some specs for comparison, shall we?
 
 
Build Quality
 
Tl;dr: Great build quality. Not much to complain about, except perhaps the color doesn’t exactly match the rest of the X7.
 
The AM2 amp module continues the tradition of great build quality as found in the rest of the X7. The metal feels smooth and polished, with no rough edges. AM2 snaps in easily and is flush to the rest of the X7’s body, where it remains tight and secure once you put in the included screws.
 
It pretty much looks like it belongs with the rest of the player, if it weren’t for the fact that it’s a much darker shade of grey compared to the rest of the X7’s brighter silver color. Honestly, this isn’t such a big deal for me since I’m not looking at the player for much of the time, but it is a bit weird to see three different shades of grey on the back of the player when AM2 is attached (one at the top, one in the middle, and AM2 on the bottom). There’s also the fact that you won’t notice this at all if you buy a cover for the X7.
 
Pretty much no complaints from me here.
 
 
 
Battery Life
 
Tl;dr: You take a bit of a hit to battery life compared to AM1, but to me it’s a good compromise between driving power and power consumption.
 
Unfortunately, more power on tap means that the battery life will inevitably suffer. However, in the AM2’s case this isn’t as bad as you might think it to be.
 
I conducted my battery life testing under the following conditions: the X7 powering the Etymotic ER4S at low gain at a volume level of 39, using the FiiO Music app in Android mode, and with the screen, pulsar light, Wi-Fi, and Bluetooth off. The music the X7 cycled through was mixture of CD-quality and high-res FLAC, as well as some DSD tracks. CD-quality FLAC tracks made up the vast majority of the music.
 
Under those constraints, as seen in the screenshot below I managed to get 7 hours and 41 minutes of playtime. In comparison, with the AM1 amp module volume-matched and under the same conditions, I got 8 hours and 22 minutes of playtime. With the AM2 amp module under the same conditions and volume-matched, the X7 could play for 7 hours and 41 minutes. With AM3 SE powering the same headphones volume-matched and playing under the same conditions, the X7 could squeeze out 7 hours and 14 minutes out of its battery.
 
In my opinion, this isn’t bad at all, considering I get decently more power to drive headphones but lose less than an hour of battery life. However, there’s no doubt that if you want the most battery life at all costs, get the AM1.
 
 
 
Sound Quality
 
Tl;dr:  The AM2 does very well with IEMs, and decently with moderately power-hungry full-size headphones. It’s a clear step up from AM1, however as expected it does lose out to AM5 and AM3 balanced.
 
Headphones primarily tested with: FiiO EX1/Dunu Titan 1, Etymotic ER4S, Hifiman HE-400i, and Sennheiser HD700.
 
Ok, enough with the build quality and battery life. How does it sound, you might ask?
 
I would say that the AM2 has a mostly neutral tone, perhaps a bit “relaxed” or some might call that a bit “warm.” Despite this overall character, AM2 is still quite detailed and has pretty good separation. This, combined with the moderately wide but with good depth soundstage, means that the AM2 provides some very good imaging (horizontal sounds) and layering (easily perceiving how close or far away sounds are). Another way to say all of this is that AM2 presents a convincing and coherent 3D soundstage.
 
AM2 also has enough power and finesse to drive almost all IEMs and even enough power to drive moderately power-hungry full-size headphones adequately, if not perfectly. For example, the AM2 drove both the FiiO EX1 (16 ohms) and the Etymotic ER4S (100 ohms) without hiss and without lacking power. The AM2 also powered my Hifiman HE-400i and Sennheiser HD700 pretty well, though by comparison to the AM5 amp module the AM2 did lack a bit here.
 
Volume-Matched Comparisons
 
All comparisons here were conducted under volume-matching with a C-weighted SPL meter.
 
Vs. AM1
 
The AM1 in comparison to the AM2 has a slightly wider soundstage. It also sounds “brighter” and a little more “metallic” and “brittle.” The AM2, in contrast, sounds somewhat “warmer” but also more natural in that notes are still as detailed without sounding like the detail is forced. This also means that stuff like vocals are given more “depth” and nuance on AM2. AM2’s soundstage is also very slightly narrower but also slightly deeper, making for a more 3D soundstage in which it is easier to perceive depth and layering of notes.
 
Separation and bass response sound about the same to me on AM1 and AM2. Perhaps some might say that the AM2 sounds “bassier” because of its more relaxed mids and treble.
 
All of the aforementioned characteristics are audible even on something as easy to drive as the FiiO EX1 IEM. The extra power also makes it so that the bass is more prominent and notes are less strained and grainy on full-size headphones being powered by the AM2 compared to the AM1. Overall, I think the AM2 sounds better than the AM1 no matter what headphone or IEM you are using.
 
Vs. AM5
 
AM2 and AM5 for the most part sound very, very similar. However, notes seemed to be a bit clearer, perhaps sharpened up a bit (but not overdone) on AM5. This can, for example, make wind instruments seem a tiny bit airier and vocals a bit “breathier.” AM5 also perhaps has a slightly wider soundstage, but depth of the soundstage is comparable between the two. I must emphasize that all of these differences are relatively minor.
 
To be honest, there’s not much improvement (if at all) in going to AM5 over AM2 for IEMs, even for harder-to-drive ones such as the ER4S. However, there seems to be an audible, if not major, improvement in using AM5 over AM2 to drive full-size headphones – for the HD700 and HE-400i, I thought I heard on AM5 that notes were slightly less grainy, slightly more open-sounding, that there was slightly more hard-hitting bass, and with slightly more separation.
 
So AM2 or AM5? Honestly, I think the biggest difference between the two is really how much power each can provide, and so this really depends on what type of headphones you listen to. If you mostly listen to IEMs with perhaps the occasional moderately power-hungry full-size headphone, go for AM2 because it has better battery life. If you frequently listen to hard-to-drive full size headphones, go with AM5.
 
Vs. AM3
 
First off, overall AM2 sounds very similar to AM3 in terms of soundstage size, detail retrieval, separation, imaging, etc. Perhaps AM3 is very slightly “sharper” and clearer sounding than AM2, but honestly I could just be imagining it.
 
As for AM3 SE vs. AM2, the AM2 is as capable as AM3 SE in powering IEMs (even more power-hungry ones). I honestly can’t tell much of a difference here.
 
However, for full-size headphones, AM2 actually comes out ahead. AM2, to me, simply produces less grainy notes and better-controlled and better-textured bass than AM3 SE when powering larger headphones.
 
But with AM3 balanced, the tables completely turn. (At least with full-size headphones, since I don’t have any balanced IEMs to test with.) Notes sound more airy and less constrained than on AM2. Bass is also deeper, more well-textured, and better-controlled. AM3 balanced’s soundstage is also slightly wider and deeper, and separation on AM3 bal. is also noticeably better (which also leads to better imaging and layering/depth perception).
 
So if you are planning to just use single-ended headphones, go with AM2 since it sounds just as good or better (depending on the headphone) with better battery life. But if you want to get the most out of your larger headphones, go with AM3 balanced.
 
 
 
Conclusion
 
Tl;dr: The first and last sentence of the next paragraph.
 
At only $99, the AM2 amp module is a relatively affordable way to not only give your X7 a bit more power to drive a wider range of headphones, but also a boost in overall sound quality. If you really want the most out of battery life for the X7 and mostly use IEMs, get the X7 with the AM1 amp module as it provides the best battery life and it does still sound pretty decent. However, if you don’t mind somewhat lower battery life, get the AM2 as I do think it gives a noticeable increase in sound quality no matter what headphone you use. The AM2 very well may be the most suitable amp module for most people, as to me it gives the best combination of battery life and driving power.
 
Thanks for reading this (somewhat) long review of the AM2 amp module!

EDIT 2/22/2016: I’ve updated the review with some notes on DLNA (under Wi-Fi and Bluetooth section), USB DAC, and the user interface due to the new FW 1.8.
 
Table of Contents

• Introduction
  • A special note
• General Usage
  • Build Quality
  • Ergonomics (physically)
  • User Interface
  • Wi-Fi and Bluetooth, DLNA
  • USB DAC
  • Battery Life
• Sound Quality
  • Comparisons (volume-matched)
  • Comparisons (non volume-matched)
• For whom is this good for? And the Competition
• Conclusion

 
(Before I even begin with the introduction, I want to warn the reader that my review is somewhat lengthy. So I have included a table of contents above which you can click on to jump to whichever section you want. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself. Also a special note regarding this review compared to others as of January 2016.
 
A little bit about me: I consider myself to be a relatively inexperienced audiophile, having only taken this hobby seriously for the past 2 or 3 years. Funnily enough, I actually began to take an interest in my headphone system with the purchase of a FiiO E7. The next logical upgrade from there was the FiiO E17, which I appreciated but soon found it a bit lacking in sound quality after I was exposed to other audio equipment. Now, after having been away from FiiO for a while I’m now looking for a great sounding DAP, which FiiO’s X series of players seem to be.
 
I tend to like a neutral sound signature, perhaps with a bit of warmth. But if one were to ask me to pick between a very warm or a very bright sound signature, I’d go towards the brighter one. I actually like full-sized headphones more than I do IEMs, but for this review I focus more on the X7’s performance with IEMs. I like a large variety of music including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.
 
A special note…
 
Before I go into the review proper, I wanted to mention this. Since I was fortunate enough (maybe?) to be the last one in the tour group to receive the X7, I have been able to use the X7 on the latest firmware as of this moment (February 2016) which is FW 1.8. Thus, I hope to give a better picture on how the X7 performs now compared to the other earlier reviews.
 
Phew, that was a long introduction. Let’s get into the actual review, shall we?
 
 
General Usage
 
Tl;dr: Great build quality and mostly good ergonomics. The X7 feels quick and responsive. UI is mostly great, but due to some minor issues not yet perfect. Some of the ergonomic and UI issues can and will be solved with future updates. Battery life is decent, but not mind-blowing.
 
Build Quality
 
Nobody is going to mistake the X7 for a cheap device once they actually feel it. The machined aluminum looks and feels classy. The amp module tightly screwed in isn’t loose and really feels like it was originally part of the whole. Some people have raised concerns about the raised screen, but honestly I don’t really think there’s anything wrong with it – it doesn’t impede usability nor does it look cheap to me.
 
The one thing I am lukewarm about is the screen - it’s merely OK. Compared to other Android and Apple devices, the X7’s screen looks a bit washed-out. Contrast is ok (so blacks look a bit gray) and colors seem a bit faded out. To be honest, I actually think (based on memory) the X5 2^nd gen screen had better contrast and slightly more vibrant colors. However, due to the screen being an IPS panel, viewing angles are pretty good though you will notice colors getting somewhat darker at extreme angles.
 
Overall, FiiO’s reputation for great build quality is once again on show here.
 
Ergonomics
 
First off, the player feels great to hold in the hand. The machined and smooth aluminum feels good and doesn’t make the X7 too slippery in the hand. The size is also great – due to the 4 inch screen and relatively narrow width, one-handed usability is excellent. The X7 is a bit tall, but this is due to the amp module so it doesn’t affect general usage.
 
While the device is thick compared to other smartphones, it still fits easily into the hand. The X7 surprisingly also doesn’t get very hot in the hand while using it – it seems to only get hot when connected to a beefy charger.
 
 
 
I would like to call special attention to the symmetrical side buttons. The buttons protrude just enough to feel, have satisfying tactile and audible feedback, and are easily accessible. However, having owned many smartphones with the volume buttons on the right, I found myself getting confused and accidentally hitting the track skip forward and backwards buttons on the right when I really wanted to change the volume (the buttons for those are on the left on the X7). This is not a huge problem, and it will be solved with a future firmware update that incorporates mapping those side buttons to user preference. But it is something that I wanted to point out at this time.
 
User Interface
 
Is the X7 responsive? While you don’t need lots of RAM and an extremely fast CPU to play music, I do know that Android is fairly unforgiving to slow hardware. However, I’m glad to say that the FiiO X7 is extremely responsive and quick even with its weaker CPU and only 1GB of RAM. FiiO has optimized its version of Android 4.4.4 pretty well, so loading and switching between apps is quick. And it doesn’t crash and freeze much now. There are exceptions though, like with one time I connected a 64GB USB stick full of music while in the FiiO Music app and that pretty much froze the device.
 
Also, as of FW 1.5, the Google Play Store and framework seems to be implemented so that one can easily get their apps. The X7 has also worked with every app that I have thrown at it, including stuff like Google Play Music. Occasionally, the “Google Play Services has stopped working” message will come up, but it’s a minor annoyance that can be brushed away with a quick tap.
 
So it feels snappy and actually works. What about the actual user interface? I want to make some comments here, but I will not go into an in-depth overview of everything it has – there are other reviews which do a much better job than I ever could.
 
FiiO’s version of Android is mostly stock Android, so most Android users will probably know how to navigate around the X7. That’s good. I also like how the X7 now automatically prompts you to reboot to switch between Android and Pure Music modes, saving us from confusion. However, I would have liked FiiO to tell us during initial setup that pulling down the top of the screen from the left (goes to notifications) and right side (goes to quick settings) yields different results. Most builds of Android I’ve seen don’t do this.
As for the FiiO Music app itself, generally I like it. The help screens mostly do a good job of telling you how to use it, and the app itself is fairly intuitive. The good thing is that FiiO has been listening to user suggestions and is still constantly improving it. For instance, hitting back/rewind after the current track has played for 10 seconds or more goes back to the beginning of the track now (instead of going to the previous track), and by default tapping on an artist in artist view leads to a list of albums instead of a list of songs.
 
However, I still have some issues with it. For example, while search works quickly and effectively, its behavior is kind of strange. Why is it that when we tap on an artist in search, that it starts to play tracks by album order? Why is it that when we tap on an album in search, that the first song alphabetically in the album starts playing? Not only are these behaviors different from other music players, it also is inconsistent.
 
One last thing I wanted to mention is the lock-screen. The lock-screen as it is right now is kind of confusing, because the music control buttons that show up by default are only for FiiO Music. So it’s possible to have Spotify be playing and then accidentally also play something from FiiO Music at the same time because you hit play on the lock screen. It would be nice if the default set of lock-screen music controls does whatever you want on the music app you were last or currently using.
 
While it seems like I have a lot to complain about the X7’s user interface, in reality these issues are relatively minor and don’t get in the way much. And what I brought up as problems can all be solved with software and firmware updates.
 
Wi-Fi and Bluetooth, DLNA
 
Wi-Fi strength on this device is ok. I would imagine it is good enough for most people if they are around some decently strong Wi-Fi, but the X7 may struggle with some places with troublesome signal. The X7 seems to get less signal and slower Wi-Fi than other Android smartphones in my testing. However, it should be good enough for most music streaming.
 
Bluetooth works well on the X7. It doesn’t have aptX so you’re not going to get the best quality sound, but Bluetooth signal on the X7 was as strong as any other smartphone out there.
 
As of FW 1.8, FiiO has implemented DLNA into their music app. However, for some reason I cannot get it to work properly. If I set up DLNA with Windows’ music sharing feature as shown in FiiO’s own guide, I can’t get any music file to show up. If I set up DLNA through foobar2000 using a plug-in, I can only get lossy files to show up and play (which it then does flawlessly – however album art doesn’t show up, which other apps can do). That is, WAV, FLAC, other lossless formats, and even DSD doesn’t show up in that case. Perhaps others have had better luck in getting DLNA through the FiiO music app to work. However, I do want to note that third party DLNA apps on the Google Play Store (such as BubbleUPnP) do work perfectly.
 
USB DAC
 
FiiO has implemented USB DAC functionality as of FW 1.8. As long as you are only listening to music on your computer, it works well. For Windows 8 and later, you still have to disable driver signature enforcement to get the driver to install, but this isn’t hard (especially for those who already own FiiO’s other DAPs). After installation, I found the driver to be stable and work well on Windows 7, 8.1, and 10 – no causing the computer to crash or anything, no incompatibilities with any of the apps I tried.
 
However, the USB DAC function still isn’t perfect as of FW 1.8. One problem is that DSD doesn’t work properly over USB. For some reason, DSD shows up as 24 bit 176.4 kHz music on the X7’s USB DAC screen when being played, and is played at an extremely low volume with lots of white noise. However, the bigger problem is that there is currently lots of lag/delay to the sound when the X7 is used as a USB DAC on Windows 7, 8.1, and 10 (and from other reports on Mac too). Unfortunately, this makes using the X7 to watch movies or to play video games on the computer impossible. Playing music is still okay though. The good news is that FiiO has already acknowledged this delay problem and it will probably be fixed in a future firmware update.  
 
Battery Life
 
While I wouldn’t say that the X7 has great battery life, I do think it has good battery life that’s in line with FiiO’s other players.
 
Below, I have some screenshots of how long the battery lasted in several different usages. All tests were done with the X7 on low gain at a volume level of 55 driving the Etymotic ER4PT (except for the line-out and Bluetooth cases).
 
First from the left on the 1st row is the battery time from the X7 in Pure Music mode and in airplane mode – a little over 8 hours.
 
Second from the left on the 1st row is the battery time from the X7 in Pure Music mode and in airplane mode hooked up to a Cavalli Audio Liquid Carbon headphone amp through line-out. It reads a little over 10 hours, though you could probably add an hour or so to that since I accidentally left on Bluetooth at first.
 
Third from the left (the right-most) on the 1st row is the X7 in Android mode and in airplane mode but with Wi-Fi turned on (Android allows you to do this), streaming from a DLNA server using the BubbleUPnP Android app. About 7.5 hours here.
 
Finally, the bottom (2nd row) picture shows that the X7 had about 66% battery left after about 10 hours on Bluetooth in the FiiO music app. I gave up testing Bluetooth battery life testing after this point because I didn’t want to recharge my Bluetooth receiver after it died first. It’ll last pretty long under Bluetooth.
 
 
 
Overall, the X7 has decent battery life that should be enough for many people unless you’re listening to music for long periods of time without access to a charger.
 
Sound Quality
 
 
Tl;dr: The X7 sounds great. DAC section sounds especially great – can go against desktop equipment here. IEM amp module also handles IEMs and some full-size headphones pretty well, though I hesitate it to call it the best for those.  Holds its own in terms of sound quality against its DAP competitors.
 
Headphones primarily tested with: Etymotic ER4PT (with P-to-S converter) and Klipsch Image X10.
 
Enough about general usage. How does it sound, you may ask?
 
Overall, I find that the X7 has a neutral tone, with perhaps a very slight bit of warmth. This allows it to pair well with warmer headphones like the Klipsch X10 – the neutrality prevents the X10 from sounding too muddy and bloated, but yet still maintains the X10’s overall warm nature. However, with something like the Etymotic ER4S, the neutrality may be too much of a good thing – I can easily see how some people would regard this pairing a bit fatiguing (but not sibilant) depending on the music being played.
 
I actually think that this brightness is probably due more to the amp, as I found the DAC section mostly neutral. While we are on the subject, the IEM amp module seems to handle in-ear monitors pretty well. The X7’s amp could slightly enlarge the soundstage of my 50 ohm Klipsch X10’s and give it better separation while also giving it hard-hitting bass. The X7’s amp also allowed the clarity, separation, and detail retrieval of the 100 ohm Etymotic ER4S to shine through. Easy to drive full-sized headphones like the Sennheiser HD598 are also pretty good on the IEM amp – huge soundstage and excellent imaging, though the bass here doesn’t come out as much as I have heard on the best amps. It also actually did a fairly good job with the Hifiman HE-400i, though it was lacking bass. But the X7’s IEM amp module didn’t do such a great job with the Sennheiser HD700 – it was a bit lacking bass and was somewhat grainy, though interestingly it made the HD700 less fatiguing like only good amps can do.
 
Since I don’t have any other portable amps to compare to, I won’t be doing amp comparisons in the next section. However, I do want to say the X7’s IEM amp is not far behind the single-ended out of the Cavalli Audio Liquid Carbon when driving IEM’s – its slightly less deep in the soundstage, a bit fuzzier in its imaging, and a bit behind in detail retrieval, but the overall feeling of a 3D soundstage is quite comparable. I do like the slightly warmer tone of the LC though.
 
Speaking of soundstage, I really like the X7’s take on this. While its soundstage is fairly wide, it’s also pretty deep. When combined with the excellent layering, separation, and imaging, the X7 presents a truly 3D soundstage that makes songs come to life as you easily pick out all of the sounds around you.
 
Lastly, the X7 has very good, even excellent detail retrieval. While detail is somewhat put into your face, it’s a lot less so compared to other ESS Sabre implementations I have heard. I would say that it only sounds that way though if you have heard other audio gear that presents the same amount of detail but is less forward about it (like with highly expensive audio gear that costs much more than the X7).
 
Comparisons
 
Volume-matched comparisons
 
The comparison here was done under volume-matching with a C-weighted SPL meter.
 
Vs. the NuForce UDH-100
 
 
I think I should give an introduction to the NuForce UDH-100 here, since it isn’t very well-known. The UDH-100 is a discontinued $650 MSRP amp/DAC combo. The DAC section should be very similar, if not identical to the NuForce DAC-80 ($800 MSRP) and to the NuForce DAC-100 ($1100 MSRP, discontinued). The X7 has quite the fight here.
 
I am only comparing the DAC sections of the X7 and the UDH-100 here.
 
As for specific methodology, I compared the UDH-100’s AK4390 DAC chip to the FiiO X7’s ESS ES9018S using the Cavalli Audio Liquid Carbon amp. Headphones that I used to compare the two DACs were the aforementioned IEMs and the Hifiman HE-400i and HE1000, and the Sennheiser HD700.
 
The DAC sections: The two DACs have similar tonality to each other. Both are mostly neutral, but with a tiny hint of warmth. Detail retrieval and separation are about the same for both DACs. However, imaging (both horizontal and depth-wise) seems to be slightly more precise on the UDH-100. On vocals and certain notes, the X7 also seems to have a slightly harsh and brittle edge that is not present on the UDH-100 – but this is not easily noticeable. Vocals seem to have a bit more body on the UDH-100.
 
However, all of the differences I just mentioned are really quite minor. What’s more noticeable is the bigger soundstage and better quality bass on the UDH-100. The soundstage is noticeably wider on the UDH-100. Bass seems to dig deeper and is slightly more nuanced/textured on the UDH-100.
 
Overall, to my ears the X7’s DAC is very close to the one in the UDH-100 in terms of sound quality. The UDH-100 still has some traits that propel it above the X7 in terms of DAC quality, but the X7 is still very impressive for keeping up with a not inexpensive desktop DAC.
 
Non-volume matched comparisons
 
Normally, I try to volume-match any comparison I make for a review. However, in this case I was able to compare the X7 to some other DAPs in relatively good conditions outside my home – but that meant not having access to my trusty SPL meter. So I tried to do volume-matching by ear, which isn’t ideal but should be better than nothing at all.
 
Hopefully people find this section interesting and helpful.
 
Vs. the FiiO X5 2^nd gen
 
Comparisons between the two DAPs were done with an Etymotic ER4S and a Sennheiser HD650.
 
The X7 surprised me because it was a noticeable jump in sound quality over the X5 2^nd gen. Not only was detail retrieval and separation slightly greater on the X7, bass was also definitely more controlled on the X7. The X7 also had a noticeably more 3D soundstage due to the greater depth (while width was about the same) and more precise imaging. All of these traits were noticeable even when comparing the X7 with the IEM amp module to the X5 2^nd gen. While each of these aspects are minor individually, together they add up to make for noticeably richer listening experience on the X7 over the X5 2^nd gen – even on the IEM amp module. With the future, more powerful amp modules, I expect the X7 to have an even more noticeable jump in sound quality compared to the X5 2^nd gen with harder-to-drive headphones. This is based on having listened to the medium power amp, which only served to further tighten and deepen the bass on the HD650 while also very slightly expanding the soundstage on that headphone.
 
Vs. the Onkyo DP-X1 and Pioneer XDP-100R
 
I listened to all of these DAPs out of their single-ended headphone jack, all with the Etymotic ER4S.
 
First off, I thought the X7 to be simply better than the Pioneer. While detail retrieval levels and imaging between the two DAPs were about the same, I thought the X7 had a noticeably deeper and 3D soundstage. Separation on the X7 seemed to be somewhat better too. Both had a similar tonality though, with the Pioneer perhaps being slightly brighter.
 
However, the Onkyo DP-X1 is much more of a match to the X7 in overall sound quality. Honestly, I believe that the X7 and the DP-X1 are pretty much equals in just about everything – detail retrieval, bass quality, 3D soundstage, etc. The only major difference I could find between the two players was the tonality – the X7 is more neutral while the Onkyo adopts a somewhat warmer tone. The Onkyo paired very well with my ER4S (probably even better than the X7), but I think the X7 has the potential to pair well with more headphones than the DP-X1. Some headphones could definitely get a bit too warm with the Onkyo.
 
 
For whom is this good for? And the competition.
 
Tl:dr: Anybody who can tolerate touchscreens and wants serious sound quality in their pocket should consider the X7, even with other great choices on the market.
 
First of all, anybody who can’t stand touchscreens at all really should not be looking at the X7 – there are other great-sounding players out there that don’t use touchscreens, some of which are from FiiO themselves (X3ii and X5ii) and other brands (Hifiman HM901S, anybody?).
 
But for everybody else, the X7 is great-sounding touchscreen DAP. It feels fluid and responsive, has lots of connectivity options for multiple usage scenarios (line-out for hooking up to a bigger sound system, Bluetooth for some cars, etc.), and most importantly sounds really good. Battery life, while not great, is also decent enough for most people I imagine. I mean, who has a commute that lasts 7-10 hours the X7 can play music for? Or does anybody actually listen to that much music at work all the time without a charger? I’m not saying that there aren’t people in that situation, but I would think that most people don’t fall into those categories.
 
Also, people who already have other FiiO products like the X5 2^nd gen could seriously consider upgrading to the X7. Not only are you getting noticeably better sound with the X7, it also comes with an entire well-implemented touchscreen interface. I think that warrants the extra $300 USD for the X7 over the X5 2^nd gen.
 
Finally, we consider the competition. I’m not going to talk much about much of Astell and Kern’s lineup nor the Sony NW-ZX2 since I haven’t listened to them a lot. I’ll just say that the X7 is significantly cheaper.
 
But let’s look at some more similarly priced DAPs. First the Pioneer XDP-100R. If you buy the XDP-100R in the US through Amazon, as of this writing it costs $699 USD. While the Pioneer does have a better screen, two micro SD slots (the X7 only has one), potentially better battery life, and faster hardware (arguably not very useful), I found it to have inferior sound quality. Personally, I’d go for the slightly cheaper X7 at $650 USD because it sounds better while maintaining most of the same functionality. Of course, you could import the Pioneer through PriceJapan for $565 USD, making it cheaper than the X7. However, you would have to go through more hoops when using your warranty. And the X7 has more future potential due to the changeable amp modules.
 
And then there’s the Onkyo DP-X1, which has a MSRP of $899 in the US. That makes it quite a bit more expensive than the equally great sounding X7, although the DP-X1 has more micro SD slots, better screen, potentially better battery life and faster hardware. You could also get it through PriceJapan for $643 USD as of this writing. Is the DP-X1 really worth that extra money (if you get it through retail channels) or the potential extra hassle in warranty claims (if you import it)? That really depends on the person, and I could see why someone would go for the Onkyo because it does sound as good as the X7 while having some advantages over it. Also, again the X7 has more future potential due to the swappable amp modules.
 
Conclusion
 
Tl;dr: The X7 is a value-packed and highly recommended digital audio player.
 
I think this review has gone on for too long, so I’ll end with a brief summary. The FiiO X7 is a fantastic sounding, great feeling, competitively priced, snappy Android-based touchscreen DAP. It currently does have some minor ergonomic and UI issues, but most of these will probably be solved with software updates. One thing it really has going for it is its immense future potential in terms of both software updates, and in hardware (the more powerful amp modules).
 
Overall, I’m going to give the FiiO X7 4.5 out of 5 stars for now due to it being a well-executed overall package that’s just a bit short. Once FiiO adds more functionality (mapping of the side buttons, USB DAC, etc.) and fixes its UI problems, it’s definitely worth 5 stars. Definitely recommended.
 
Thanks for reading this long review of the X7!
 

Table of Contents

• Introduction
• Build Quality and Ergonomics
• General Usage

[*]Sound Quality

• Comparisons to other audio gear

[*]For whom is this good for? [*]Conclusion  
(Before I even begin with the introduction, I want to warn the reader that my review is somewhat lengthy. So I have included a table of contents above which you can click on to jump to whichever section you want. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: Aune lent me the unit for my honest opinion, and a bit of background about myself.
 
Before I begin my review, I would like to thank the team at Aune for letting me try out their X1s for five business days (about a week). Aune has not paid me whatsoever in the making of this review and has only asked for my honest opinion.
 
A little bit about me so you know where I’m coming from: I consider myself to be a relatively inexperienced audiophile, having only taken this hobby seriously for the past 2 or 3 years. I actually began to take an interest in my headphone system with the purchase of a FiiO E7, which was already a significant step up from the onboard computer audio that I was previously listening to. The next logical upgrade from there was the FiiO E17, which I bought and appreciated but soon found it a bit lacking in sound quality after I was exposed to different headphones and audio equipment. For the next year or two, I began to steadily upgrade my desktop audio gear and headphones, the full of list of which you can see in my profile. One of those upgrades along the way was the original Aune T1, so I do have previous experience with Aune equipment.
 
A bit more about me: I tend to like a neutral sound signature, perhaps with a bit of warmth. But if one were to ask me to pick between a very warm or a very bright sound signature, I’d go towards the brighter one. I actually like full-sized headphones more than I do IEMs, but I do cover how well the Aune X1s does with both in this review. As for what kind of music I listen to, I like a large variety including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.
 
With all of that out of the way, let’s jump into the actual review.
 
 
 
Build Quality, Ergonomics, and General Usage
 
Tl;dr: The Aune X1s feels great all-around, really has no ergonomic problems and has lots of features that make it handy. Filter selection is not immediately intuitive but is still easily done. Windows and Android compatibility is flawless. It doesn’t get hot at all.
 
Build Quality and Ergonomics
 
Overall, the Aune X1s is built really well – it’s built solidly and the materials used feel premium to the touch.
 
There are no big gaps anywhere in the construction, the buttons and switches all are nice to touch and have a satisfying click and tactile feedback, and the volume knob especially feels great to move (continuing in the tradition of the equally excellent volume knob of the Aune T1). It’s big, easy to grab, and has just the right amount of resistance so that it doesn’t feel cheap but it’s easy enough to move in order to dial in very fine volume adjustments.
 
The LED lights on the front of the unit are bright enough so that one can easily notice them, and at least in my experience with the X1s they also aren’t so bright as to bathe your entirely dark room with light. Others have mentioned about the low-contrast text on the unit which makes it harder to see. I agree, but in my case I don’t really care about it so much because I’m not really looking at that text during most of the time that I am using the X1s.
 
The power switch for the X1s is on the back. It’s not hard to find (even by feel) and is easy to toggle. Personally, I prefer power switches on the front of the unit because they’re more convenient. But I don’t think the rear power switch is going to be headache for anybody regardless of their preferences or if they are already used to a rear power switch or not.
 
The metal material that is used for the body of the X1s is also really nice. Honestly, I don’t really think that the Aune X1s looks or feels any worse in the metal body and the overall build quality compared to much my more expensive NuForce UDH-100.
 
About the huge power block with the X1s – it is kind of a pain, and may actually be a hindrance to some setups, but I would imagine for many people once you get it set up and out of the way it shouldn’t be much of a problem. For anybody that owns the original Aune T1, this won’t be a problem, as the power block on the X1s is only slightly larger than that of the T1.
 
General Usage
 
In general, the Aune X1s is really easy and convenient to use.
 
Setting which filter to use for me wasn’t that difficult – at least once I got used to it. Basically, what you have to do is to hold down the input selection button until the color of the light turns orange. Keep holding down the button until the light moves to the corresponding position/filter that you want. As soon as the light goes to the desired filter, let go of the button and the light should both turn green and return back to whatever input you were using. The orange light in the “USB” position should signify that the “fast” filter is currently chosen, if in the “OPT” position it should signify the “slow” filter, and the “COAX” position should signify the “minimum phase” filter. It may not be the most obvious thing to do, but once you get the hang of it, it really isn’t that difficult.
 
I also really like how the X1s can be used in a variety of ways, making it very useful. Besides using the DAC and headphone amp together, each can be used separately on its own. This is especially important to me because I can’t even use the headphone amp built into my more expensive NuForce UDH-100 on its own, which I’ve wanted to hook up to other sources. Besides those functions, the X1s also offers optical and coaxial inputs to take care of your digital connection needs. Even though I didn’t test this function, what’s really interesting is that the X1s can also be used essentially as a USB-to-coaxial converter, which makes it useful if you’re trying to hook up your PC to something like an older DAC that doesn’t have USB inputs. Having all of these features really bumps up the Aune’s value proposition.
 
The Windows driver is flawless – this is having tested it on Windows 7, 8.1, and 10. During the course of my evaluation, it simply never failed on me – not even once. This is actually better than most other drivers for audio gear, where at least on one occasion I would notice some kind of glitch, even if small and minor. It’s also easy to install (no having to disable driver signature verification like with the FiiO driver), and even DSD setup is relatively painless because Aune has included all of the necessary files (at least for foobar2000) and instructions within the USB memory stick that also contains the manual.
 
Android USB OTG compatibility is also pretty much flawless. Audio over USB OTG pretty much just worked after I plugged the X1s in, at least when testing with the HTC One M7 (on Android 5.0.2), Sony Xperia Z Ultra (on Android 5.0.2), the Sony Xperia T (on Android 4.3), and the Sony Xperia T2 Ultra (on Android 5.1.1).
 
One thing that I noted about the Aune X1s is that it never really got even warm. It was always cold, or at most, room temperature to the touch. This was the case no matter what type of headphone I plugged into the unit – whether it be the Etymotic ER4S IEM, the Sennheiser HD700, or even the power-hungry Hifiman HE1000. This is not really a pro nor a con, but it was just something that I thought I would mention.
 
Sound Quality
 
Tl;dr: Overall has pretty good sound, except for how I think all of the filters except for the “fast”one mess with the imaging, and how there is channel volume imbalance at lower volumes. It’s a solid upgrade from the Aune T1 in terms of sound, and while it doesn’t quite match up to my more expensive NuForce UDH-100, it still sounds not half-bad. Overall, it’s a great value if looking at sound quality.
 
Headphones tested with: Klipsch Image X10, Etymotic ER4PT (with P-to-S converter), Sennheiser HD598, Sennheiser HD700, Fostex T50RP (self-modded), Hifiman HE-400i and HE1000.
 
Now to the juicy part of this review. How does the Aune X1s sound?
 
Overall, I find the X1s has to have a mostly neutral sound signature that leans slightly towards the bright side. This allows it to pair well with warmer sounding headphones. For example, I liked how the X1s made both my modded Fostex T50RP (which I deliberately tuned to be warmer) and my Klipsch Image X10 to have slightly less emphasis on the bass so as to make vocals and treble stand out a bit more, but still gave it lots of good sounding and hard-hitting bass. It also paired well with the slightly warm HE-400i and the HE1000, making them a bit brighter than what I am normally used to but still sounded great. With the ER4PT in both its PT and S incarnations, the pairing with the X1s sounded a bit bright but never sibilant or really fatiguing. With the HD700, it did sound a bit close to what I would call tiring and did sound a bit sibilant. But I actually consider myself to be a bit more treble tolerant than others, so I could see how the pairing the X1s with something like the HD700 could be problematic for some.
 
The sound from the X1s is very punchy, dynamic and lively. Bass comes through very distinctly, cleanly, and as very hard-hitting on pretty much all of the headphones that I tried, which gives music that quality that makes you want to dance to it. This is no doubt at least partly due to the great amp, which I found to drive all of my headphones very well with no real hints of graininess that is characteristic of not being powerful enough (even the HE1000 didn’t sound very underpowered when paired with the X1s).
 
Soundstage on the X1s is a highlight. It’s very wide, and with decent depth. Overall, the soundstage is very 3D in shape, and really helps headphones with great soundstage such as the HD598, HD700, and even the HE1000 to shine.
 
The X1s also has pretty good separation and layering (separating between instruments in terms of how far away they sound from you). Vocals and other instruments in the mix are well-defined, coherent, and not mashed together even in the most complicated pieces of music.
 
I found the different selectable filters on the X1s for the most part to sound the same, to the point where I’m not sure if most of the differences that I perceived were really just placebo. However, one thing that I did notice between the filters is that anything other than the “fast” filter really messed up the imaging. With the “slow” and “minimum phase” filters, I found that I could no longer really pinpoint where certain instruments were in the mix, and that instruments sounded diffuse throughout the entire soundstage. But with the “fast” filter, imaging improved greatly, and was pretty good though I wouldn’t say that it was pinpoint accurate.
  
One of the things that I didn’t like about the X1s so much is the one gain setting that it offers. For most people, I would imagine that they are going to be able to use only about 2/3 of the volume knob’s range, unless they have something like 600 ohm headphones or the Hifiman HE-6. With the HD700 and HE-400i, I’ve only set the volume knob to be at about 10-11 o’clock. Even with the HE1000 I’ve only cranked it up to the 12 o’clock position, at most at the 1 o’clock position. With IEMs, most of the time the volume knob is below the 9 o’clock position, like around 7 or 8 o’clock. Only with the 100 ohm ER4S have I set the volume at the 9 o’clock position. At least I can’t hear hiss or humming even with my 25 ohm ER4PT, with the music paused and even at max volume.
 
I actually wouldn’t have minded the one gain setting so much since the volume knob allows for very fine adjustments of volume, if it weren’t for the fact that at least with my unit, there was some pretty bad volume imbalance between the left and right channels at lower volumes. It’s quite obvious that the right channel is louder than the left channel when the volume knob is below the 9 o’clock position. Vocals and all instruments just get shifted to the right in this situation, and everything sounds off in in terms of positioning. This is mostly a problem for IEMs and sensitive full-sized headphones (like the HD598, though if you are willing to accept louder listening volumes then this isn’t an issue), for which you are likely to put the volume knob at a low enough position for this to happen. I suppose one could get around this by lowering the volume of the music through software on your computer or phone (and thus being able to turn up the volume knob on the Aune), but that is something I prefer not to do if I have an analog volume knob like on the X1s.
 
Comparisons to Other Audio Gear
 
All comparisons here were done under volume-matching with a C-weighted SPL meter.
 
Vs. the Aune T1 mk1
 
 
 
Before I go on with the rest of the comparison, I must note that I have put an Amperex Orange Globe tube (which I consider an upgrade) in my Aune T1 and am not using the stock tube.
 
Overall, the Aune X1s and the T1 when both are used as a DAC/amp combo have really similar sound signatures. I’m guessing this is probably the Aune house sound.
 
The DAC sections: I compared the DACs of the Aune X1s and the T1 using the X1s’ headphone amp. Here, the ES9018 implementation of the X1s is made to sound like a more refined version of the PCM1793 chip in the Aune T1. The X1s’ DAC is not only more airy, but also harder-hitting and presents deeper bass than in the T1. Notes are also less raspy, smoother, and better separated on the X1s. However, soundstage width and depth, as well as imaging ability, are about the same on both DACs. Overall, the X1s’ is simply clearer and more transparent than on the T1.
 
The amp sections: To compare the headphone amps in the X1s and the T1, I utilized the X1s’ DAC. For the most part, in terms of overall sound signature both amps are really similar, but the X1s’ amp sounds a bit warmer due to being able to convey more solid bass. Actually, that is one of the obvious things one will notice when comparing the two amps – the bass on the X1s’ amp is simply more coherent, tight, and hard-hitting than on the T1’s amp. Soundstage width between the two amps are about the same, though there is slightly more depth on the X1s. The Aune X1s’ amp is also a tiny bit airier, and has somewhat better separation of instruments (it’s a bit subtle, but appreciable) too. Overall, like with the DAC section, the X1s’ amp is more transparent, detailed (less hazy notes), and clearer.
 
If you compare the X1s and the T1 both as amp/DAC combos, the somewhat subtle differences between the DAC and amp sections of the two add up. With the X1s, you get smoother yet more detailed notes, more airy notes that allow stringed instruments to more clearly vibrate through the air, a deeper soundstage, better separation, more precise imaging, and bass that is harder-hitting, deeper, and yet more controlled. All of these add up to allow the X1s to obviously set itself apart from its sibling, and make it truly an upgrade from the T1.
 
Vs. the NuForce UDH-100
 
 
Yes, I know I’m crazy for comparing the X1s (MSRP $300) to my much more expensive UDH-100 (discontinued, but had a MSRP of $650). However, the X1s is the only product I’ve reviewed that upon first listen that I would even consider to compare against the NuForce, which is saying something. Here, I’m going to be trying to give a picture of how well the X1s does for its price and how good of a value it is, rather than trying to nitpick about its sound quality deficiencies in the face of much more expensive competition.
 
The DAC sections: To me, the DACs in both have a somewhat similar overall sound signature. However, the AKM 4390 implementation in the UDH-100 is appreciably warmer, making it slightly warm of neutral as opposed to the slightly brighter than neutral ES9018 implementation of the X1s. Soundstage on the X1s actually doesn’t fare all that badly against the UDH-100 – the more expensive gear has a deeper soundstage, but width between the two is the same. However, the UDH-100 is simply more detailed and transparent. Even though vocals are more forward on the X1s, the vocals on the UDH-100 are simply more vivid. The UDH-100 also has the more textured and nuanced bass, though that isn’t to say that the X1s’ bass sounds bad in comparison. There is also noticeably less treble glare on the UDH-100 than on the X1s, though my words make it sound worse than it really is.
 
The amp sections: Overall, the UDH-100’s built-in amp is better than the one in the X1s. No surprises there. The soundstage width between the two amps is similar, but there is greater depth in the UDH-10. Also, the UDH-100 simply has better separation – while the X1s is no slouch here, the UDH-100 simply doesn’t blend instruments together as much. The UDH-100’s amp also provides better imaging. Also, the UDH-100 simply provides more punch in terms of bass and in dynamic range (like in classical and orchestral music), especially with planar magnetic headphones (but the difference isn’t as big with dynamic headphones).
 
When you combine the differences in the amp and DAC sections (especially the DAC section, which I found to have a greater difference compared to the amp sections) when listening to both as DAC/amp combos, it becomes pretty clear that the UDH-100 is obviously at least one step up (if not more) than the X1s. However, considering that the Aune goes for less than half of the UDH-100 when comparing MSRP prices, has much more features (the UDH-100 only has USB input and RCA output), and doesn’t even sound all that bad next to the more expensive unit, the X1s is a pretty dang good deal.
 
For whom is this good for?
 
Tl;dr: The Aune X1s should be considered by anybody looking for a good, decently priced amp/DAC combo that is above the lowest entry level (including Aune T1 owners).
 
In my opinion, anybody who is looking for a good amp/DAC combo beyond the entry level Aune T1, O2/ODAC and the Schiit Magni/Modi combo should probably take a look at the Aune X1s. Not only does it sound better than that level of equipment to me, it also contains lots of features (lots of inputs and outputs) that make it a good value. Like with all other amp/DAC combos, I probably wouldn’t recommend it if one is just looking for a good DAC or a good amp (because one probably wouldn't want to be saddled with something they don't need if it costs more money). Well, I actually think that the DAC is good enough for one to still keep using even if upgrading to a different amp, but I don’t think that the X1s headphone amp is especially good (though that does not mean I think it is bad). Also, for anybody who already owns an Aune T1, the X1s is a logical upgrade. Not only are they getting the same excellent build quality from Aune, they are also getting a lot more features in terms of inputs and outputs and getting noticeably better sound quality for not that much more money (less than $100 difference if the street prices that I’ve seen for the X1s are anything to go by).
 
Conclusion
 
Overall, the X1s is an excellent value. For $300 MSRP, you’re getting something that looks and feels great, sounds good, works well (easy setup and no driver issues) and is really useful as a piece of audio gear (good amp, good DAC, able to even do USB-to-coaxial conversion, etc.).
 
The only major complaints I have come from the implementation of the amp. While adjusting the volume is easy and precise on the X1s, I don’t really like how there is only one fixed level of gain that is too loud of IEMS, and the left and right channel volume imbalance at lower volume levels where IEMs and other sensitive full-sized headphones will be used at.
 
So I rate the X1s at 4.5 stars out of 5. As it is, it’s already something that I very much recommend.
 
Thanks for reading my review of the Aune X1s!
 

Table of Contents

• Introduction
• Features and Ergonomics
• Sound Quality
  • With IEMS
  • With full-size headphones
  • Comparisons to other audio gear
• For whom is this player good for?
• Conclusion

 
(Before I even begin with the introduction, I want to warn the reader that my review is somewhat lengthy. So I have included a table of contents above which you can click on to jump to whichever section you want. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: Cayin lent me the unit for my honest opinion, and a bit of background about myself.
 
Before I begin my review, I would like to thank the team at Cayin for letting me evaluate their C5DAC for two weeks. Cayin has not paid me whatsoever in the making of this review and is only asking for my honest opinion.
 
A little bit about me so you know where I’m coming from: I consider myself to be a relatively inexperienced audiophile, having only taken this hobby seriously for the past 2 or 3 years. I actually began to take an interest in my headphone system with the purchase of a FiiO E7, which was already a significant step up from the onboard computer audio that I was previously listening to. The next logical upgrade from there was the FiiO E17, which I bought and appreciated but soon found it a bit lacking in sound quality after I was exposed to different headphones and audio equipment. For the next year or two, I began to steadily upgrade my desktop audio gear and headphones, the full of list of which you can see in my profile.
 
A bit more about me: I actually haven’t owned a serious DAP (the only portable music sources I’ve used are a cheapo Sony Walkman and my smartphone) even at the time of this review – hence the relative lack of comparisons to other mobile sources. I actually also like full-sized headphones more than I do IEMs, but I do cover how well the C5DAC does with both in this review. As for what kind of music I listen to, I like a large variety including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.
 
With all of that out of the way, let’s jump into the actual review.
 
 
Features and Ergonomics
 
Tl;dr: The C5DAC is packed with lots of truly useful features. Build quality is also mostly good with few issues. Great form factor for pairing with smartphones. Few glitches with its operation. Subjectively good battery life, but charging takes a while.
 
For anybody that isn’t sure, the Cayin C5DAC is a portable headphone amp/DAC combo that is designed to be used with Android devices, though it also works on personal computers and iOS devices (with the proper extra pieces for the latter).
 
As such, it comes with multiple ways to hook up your portable (or non-portable) device to it which makes it quite useful. For example, you can choose to use it as a replacement for your Android smartphone’s headphone amp and DAC by connecting the micro-USB port of your Android device to the C5DAC’s one of two micro-USB ports (the other is used simply for charging) by using the supplied mini-to-mini USB OTG cable or with your own USB OTG cable. You can also do the same for your personal computer by using a mini-to-regular USB cable. If you just want to utilize the C5DAC’s headphone amp (if you just want your smartphone to have a louder volume than it can do by itself or if utilizing another device’s DAC), you can do that too by just connecting a 3.5mm to 3.5mm stereo cable between your other device and the C5DAC’s line-in.
 
Heck, you can even use the C5DAC as a USB-to-coaxial converter since the unit has a coax out. Though I didn’t personally use this feature myself, I can see this very handy for somebody who has lots of music stored on their smartphone or tablet or personal computer and wants it to be played through a setup which contains a DAC that may not accept USB.
 
Basically, there’s lots of ways to use the C5DAC, which makes it quite the versatile tool. The only things that you really can’t do with the C5DAC is to hold and play music by itself (understandable, as it’s not a DAP) and that you can’t use the DAC by itself since there is no line-out (this is not a big loss, as I explain in further detail in the sound section of the review).
 
While the C5DAC has lots of useful features, does it look and feel well in practice? Well, to begin with, build quality is mostly solid. The metal body feels nice and gives the unit some premium-feeling heft. The plastic cover on top doesn’t feel or look as nice as the rest of the body, but it’s still acceptable considering the price of the C5DAC (which I believe is somewhere around $200 USD). The volume knob also feels great, with the finely-cut notches along its side helping you to grip the knob, and generally having a good feel when being turned. However, what I didn’t like about the C5DAC physically is that the upper and lower metal body panels seem to wiggle around a little when I put a bit of force on it. It’s not a huge deal, but it doesn’t make it feel as solid as its looks suggest it to be.
 
The size of the C5DAC is well-suited to its intended purpose of being used with mobile devices. The fact that the C5DAC is close in size in terms of length and width compared to many 4.5 to 5 inch smartphones, and how it’s only somewhat thicker than them, makes it great for stacking with such phones. I found that the C5DAC stacked well with my Sony Xperia T (4.6 inch screen), and with a HTC One M7 (4.7 inch screen), due to the C5DAC aligning almost perfectly with these phones.
 
Unfortunately, despite all the positives I’ve just said about the C5DAC, there are some drawbacks to its general usability.
 
First, at least on my unit, I’ve noticed some oddities when switching between the headphone amp mode and the DAC mode. Basically, when I switch from the former to the latter, I notice that the C5DAC constantly emits a popping sound coming out of its headphone out. This can be resolved by simply switching the unit on and off, but it is a bit annoying.
 
Secondly, for some reason the C5DAC at times simply refused to be recognized by the Android devices that I tested on. While the C5DAC mostly worked fine with a Sony Xperia T (on Android 4.3), a Sony Xperia Z Ultra (on Android 5.0.2), and a HTC One M7 (also on Android 5.0.2) throughout the Android interface and through the stock music players of each phone, for some reason the three phones sometimes simply wouldn’t recognize the C5DAC as an audio device. Then, for some inexplicable reason, the C5DAC would work with those phones again after a while – I could never exactly figure out why. This didn’t happen too often and was not consistent, but it was a part of my experience.
 
Thirdly, charging times are very, very long. While I didn’t mind the battery indicator too much (although, having only three bars, it’s hard to tell how much juice you have left when only one circle lights up – are you closer to the higher end of that one circle, or the lower end?), it always felt like it took a really long time to get it charged up to the point where all three circles were lit up and no longer blinking (a full charge). It also doesn’t help that if all three circles were lit up and not blinking, and then you decided to pull it out and plug it back in to charge (maybe you forgot you already charged it to full), the third light starts to blink again for a while – which makes it harder to know whether you’ve already charged the C5DAC fully. Despite all of this, however, the C5DAC has a relatively long lasting battery – while I didn’t time my usage exactly, I was able to squeeze out several days’ worth of listening, using it for several hours each day in DAC and headphone amp mode.
 
Sound Quality
 
Tl;dr: Overall, the C5DAC is a pretty good sounding unit, with a great amp that is let down by a mediocre DAC section. Volume gets too loud too quickly for most IEMs and easier-to-drive headphones. Soundstage is plenty wide and decently deep. Offers an upgrade to the sound quality of the better sounding smartphones. Compares well to, but isn’t better, than desktop audio equipment for around the same price range.
 
Now for the meat of this review. How does the Cayin C5DAC sound?
 
Overall, I find the C5DAC to be slightly on the warmer side tonally, though I think this is more due to the DAC, which I find to be more noticeably warm in tone compared to the headphone amp, which is only slightly warm. However, this doesn’t mean that I think that the C5DAC deviates from neutrality a lot – it’s just slightly warm of neutral, which I think will be pleasing to most people.
 
The C5DAC also tends to have somewhat of a more laid-back, somewhat non-aggressive sound. By that, I mean that vocals and notes in general aren’t pushed into your face and somewhat not punchy, kind of the opposite from what I have found with FiiO devices.
 
Unfortunately, while the included DAC is a selling point of this device, I don’t feel that it is very good. In contrast, the amp in the C5DAC is quite good.
 
For example, I like the soundstage on the C5DAC when used as a headphone amp/DAC combo (which I will refer to from now on as “DAC mode”). I think it’s quite wide, and has decent depth (though to me not as impressive as the width). Imaging and separation in DAC mode are also decent, since I am able to tell where different instruments are playing from within the music at the same time without feeling too much like they’ve also mashed into a single blob. However, I feel this is mostly due to the amp, which I found when paired with other DACs still presented a very large soundstage. In fact, when paired with other DACs, I felt that the amp of the C5DAC provided even better separation and imaging, with instruments becoming much less like blobs (which in the DAC mode felt like was on the verge of becoming) and thus being even easier to pinpoint where they were.
 
Also, notes sounded a bit fuzzy, unrefined, and somewhat lacking in detail when I listened to the C5DAC in DAC mode. I think this is mostly due to the DAC, because when I paired the C5DAC’s amp with other DACs, I found that notes came through a lot more cleanly and with a lot more detail.
 
A quick word on the bass boost found in the C5DAC – I found that it actually worked pretty well. It won’t transform something that was originally bass-light into a bass monster, but it gives a nice increase to the mid-bass (rather than sub-bass) of a headphone that may be lacking bass or a bit analytical for one’s taste. For example, I found that the bass boost seems to bump up the mid-bass of the Sennheiser HD598 just enough for a more fun sound without really affecting the mids and vocals much. Similarly, I also found that with my Etymotic ER4PT (with the adapter that converts it into an S version), it brings up the mid-bass somewhat without making it seem uncontrolled and muddying up the mids and vocals. Soundstage, separation, and imaging also did not really seem to be affected in either of those headphones.
 
With IEMs:
The IEMs that I listened to with the C5DAC were the Klipsch Image X10 and the Etymotic ER4PT (with the P-to-S converter, which essentially makes it an “ER4S”).
 
The C5DAC had more than enough power to drive both of these IEMs. The strong bass of the Klipsch X10 came through cleanly and powerfully, and the large soundstage presented by the C5DAC prevented the X10’s soundstage from collapsing onto itself which can happen with certain other audio gear. The slight warmth of the C5DAC did not make the X10 too warm, with mids being not too recessed and highs still present.
 
With the “ER4S” and its 100 ohm resistance, the C5DAC was still able to drive it without any problems. The slight warmth proved to be a good match with the analytical nature of the “ER4S”, in which mids and highs were still very present and still very much the focus but were balanced out by the slight bass increase the C5DAC added to the ER4S. The wide soundstage allowed the wide soundstage of the ER4S to come through brilliantly. The C5DAC, when used as an amp only, really allowed the details to shine on the “ER4S”, but still details were moderately plentiful when used in DAC mode due to the inherent nature of the “ER4S.”
 
As for hiss, I could not really hear it on the X10 (with 50 ohm impedance) or the ER4PT (with 25 ohm impedance) no matter how high I cranked the volume.
 
However, I do have to mention that the volume gets too loud too quickly on IEMs. It seems like the volume is at a very low, unlistenable level when one turns the volume knob from off to about 1.5. After that, the volume gets loud really quickly. Basically, by the time I turn to about 2.9 on the X10 and 3.5 on the “ER4S”, it’s already loud enough for me. And this is on low gain. And the maximum volume being a 9 as indicated on the volume knob. I know that I listen to music on a slightly lower level than most people, but still, I can’t imagine anybody going past the 5 mark with any IEM at all. With high gain, there is even less volume available to play with when using an IEM.
 
With full-size headphones:
 
The full-size headphones that I used when evaluating the C5DAC were the HiFiMAN HE-400i, Sennheiser HD598, Sennheiser HD700, and my self-modded Fostex T50RP.
 
The slightly warm nature of the C5DAC’s sound paired well with pretty much all of my full-size headphones. The warmth went well with my more neutral headphones such as the HD598 and the 400i, and definitely made the somewhat bright HD700 less fatiguing to listen to. It also didn’t make warmer headphones such as my modded T50RP (which I purposely tuned to be a bit more bass heavy) to be too warm and suffocating in its sound.
 
The C5DAC had no problems at all in powering most of the full-sized headphones that I used. Notes did not sound grainy at all with the exception of my T50RP, which is understandable since that is a power-hungry headphone and even then it wasn’t even extremely grainy in the sound. Bass was prominent and clean when the C5DAC was paired with all of my full-sized headphones.
The large soundstage, and good imaging and separation of the C5DAC (even when using the DAC) really allowed the large soundstages of the HD598 and the HD700 to shine. It even allows the 400i to sound a bit less constricted, which makes for a great listening experience.
 
Again, like with the IEMs, I found that the volume knob got too loud too quickly, even with the power-hungry T50RP. For most of these headphones I used, out of a maximum volume of 9, I was setting the volume knob at around 3.5 to 4, with me listening to the modded T50RP at about 4.5. And as with the IEMs, this was all on low gain. Even though I know that I listen to music at a lower volume than most people, I really can’t imagine many people will be able to use the full range of the volume knob on low gain when listening to full-size headphones without blowing their ears up. And that’s only on low gain.
 
Comparisons to Other Audio Gear
 
All comparisons here were done under volume-matching with a C-weighted SPL meter.
 
Vs. the HTC One M7
 
How does the C5DAC (in DAC mode) fare against the HTC One M7, which along with Apple’s iPhones are regarded as some of the better sounding smartphones that exist?
 
Overall, the C5DAC is an improvement over the smartphone. The M7 here is actually tonally brighter, with the C5DAC being relatively warmer. For some reason though, I feel there is less “glare” and artificial brightness to the sound from the M7. The HTC One also seems to be a very tiny bit more detailed (the notes are very slightly less smeared on complex passages in music). However, the C5DAC is much more dynamic in its sound, with the contrast between the quiet and loud parts being much more distinct. The soundstage is also much wider and is somewhat deeper on the C5DAC. The C5DAC also has better separation, with instruments being less clumped together. Both drive IEMs with about the same authority, but for driving cans like the HD700 and up the C5DAC has the edge. Overall, based on my experiences here, I would say the C5DAC is an upgrade to any smartphone’s sound.
 
Vs. the Aune T1 mk1
 
Here, I compared the C5DAC to the Aune T1 mk1 outfitted with upgraded Amperex Orange Globe tubes.
 
The DAC sections: I compared the DACs of the Aune T1 and the C5DAC using the C5DAC’s headphone amp. Overall, the Aune T1’s DAC is noticeable better than that of the C5DAC’s. The DAC of the Cayin unit is somehow both warmer and yet more fatiguing (has more “glare”) in its sound. The Aune T1’s DAC is also more detailed and is better able to portray texture. While the C5DAC and the Aune T1 DAC present soundstages with the same width, with the Aune T1 DAC there is more depth to the soundstage as well as better separation. Imaging is slightly more precise on the T1 DAC, although I’d say that’s due more to the T1’s better separation. There is also less flabby and “one-note” bass on the Aune T1.
 
The amp sections: For comparing the amps between the two units, I used the Aune T1’s DAC. I would say that overall, the C5DAC has a slightly better headphone amp than the T1, which is no small feat considering the latter is a desktop product that really isn’t easily transportable (due to the large wall-wart). While the T1’s amp has the harder-hitting, deeper bass, both amps are equal in terms of well-controlled bass. Both amps also provide a similar soundstage, with width being comparable between the two amps but the C5DAC amp having slightly better depth. Separation and detail levels are about the same. This sounds like as if the two amps are evenly matched, and they mostly are, except that the C5DAC’s amp just sounds more “analog.” By that, I mean that the C5DAC’s amp is smoother but just as detailed as the T1’s amp, and sounds tonally richer and with more life.
 
Value, and For Whom is this Player Good For?
 
Tl;dr: The C5DAC is a good value for anybody looking for an amp/DAC combo to upgrade their mobile device or personal computer’s audio.
 
The Cayin C5DAC should be considered by anybody who wants an upgrade to their mobile device or even personal computer’s sound, but yet doesn’t want a DAP. (This could be for a variety of reasons, including that perhaps one prefers the music player interface of their mobile device over any existing DAP, or that their main use for the C5DAC will be for their computer, and some DAPs don’t have the USB DAC functionality.) Considering all of the useful features in the C5DAC (you can use it as a amp/DAC combo, an amp only, or even as a USB-to-coax converter!) and its sound quality and its ability to drive IEMs and a decent amount of full-size headphones, the C5DAC is a good value.
 
Conclusion
 
Tl;dr: The C5DAC is a decently valued and useful portable amp/DAC combo that has some flaws that prevent it from reaching perfection.
 
Overall, I feel that the C5DAC is a great portable amp/DAC combo, with generally good ergonomics and usability, good sound quality (shame about the DAC section), and lots of features that make it such a versatile and useful piece of kit.
 
While I really like the C5DAC due to its overall usefulness as a package and thus its good value, the slight problems with its general operation (including the volume control) and its not-so-great DAC section lead me to rate it 4 stars out of 5, which is far from a bad rating.
 
Thanks for reading my review of the C5DAC!
 

Table of Contents

• Introduction
• Build Quality and Ergonomics
• Sound Quality
  • High Gain vs. Low Gain
  • Comparisons to other audio gear
• For whom is this player good for?
• Conclusion

 
(Before I even begin with the introduction, I want to warn the reader that my review is somewhat lengthy. So I have included a table of contents above which you can click on to jump to whichever section you want. I’ll also include a tl;dr summary at the beginning of each major section.)
 
Introduction
 
Tl;dr: FiiO lent me the unit for my honest opinion, and a bit of background about myself.
 
Before I begin my review, I would like to thank Joe Bloggs and the rest of the team at FiiO for letting me play with their X5 2^nd gen (from now on referred to as the X5ii) for 10 days. FiiO has not paid me whatsoever in the making of this review and is only asking for my honest opinion.
 
A little bit about me so you know where I’m coming from: I consider myself to be a relatively inexperienced audiophile, having only taken this hobby seriously for the past 2 or 3 years. Funnily enough, I actually began to take an interest in my headphone system with the purchase of a FiiO E7, which was already a significant step up from the onboard computer audio that I was previously listening to. The next logical upgrade from there was the FiiO E17, which I bought and appreciated but soon found it a bit lacking in sound quality after I was exposed to different headphones and audio equipment. Fast forward a year or two, and after having been away from FiiO for a while I’m now looking for a great sounding DAP, which FiiO’s X series of players seem to be. So I’d like to thank FiiO again for letting me evaluate their excellent players.
 
A bit more about me: I actually haven’t owned a serious DAP (the only portable music sources I’ve used are a cheapo Sony Walkman and my smartphone) even at the time of this review – hence the relative lack of comparisons to other mobile sources. I actually also like full-sized headphones more than I do IEMs, so the focus of this review will be how well the X5ii powers headphones. As for what kind of music I listen to, I like a large variety including rock, pop, jazz, classical and orchestral, J-Pop and J-Rock, and C-Pop.
 
With all of that out of the way, let’s jump into the actual review.
 
 
Build Quality and Ergonomics
Tl;dr: Build quality and ergonomics are excellent, and are definitely worth the X5ii’s asking price. No obvious glitches with the firmware or the USB DAC functionality. Responsive UI and good battery life.
 
I’m not going to focus much on the user interface (it’s responsive and fairly intuitive) of the X5ii here as other reviews have already gone over that very well. But I do want to talk about how the X5ii physically feels and overall usability (including its function as a USB DAC).
 
First of all, the overall build quality is fantastic. It feels well-built, with enough heft so that it feels like it isn’t fragile at all. Edges are nicely smoothed out, so you won’t cut yourself on any angle of this player. I also really like the brushed metal finish of the player, and it reminds me of how FiiO built their older products such as the E7 and E17, which also looked particularly nice. I actually prefer this finish to the X3 2^nd gen’s (from here on referred to as the X3ii) smooth metal finish and how the X5ii ditches the plastic (?) cover on the back compared to the X3ii, because to me these changes make the X5ii look and feel classier.
 
 
 
 
 
 
The buttons on the X5ii are not too small, easy to press down and have good feedback. Of special note are how the volume buttons and the power button are located on the upper-left side of the player. Exactly as in the X3ii, I really like how the volume and power buttons are clearly distinguished from each other by having the power button recessed enough, and how even the volume up and volume down buttons are distinguished from each other due to the volume up button having a slight protrusion to it. I also personally like how the power status indicator (whether it’s charging, on, etc.) is now integrated into the power button. This may annoy some people who were used to the X3ii and how they just had to glance at the front of the player to see its status, but I don’t really think it’s such a big deal.
 
The scroll wheel of the X5ii seems to finally have one-to-one operation – that is, one click on the scroll wheel physically leads to one movement up or down in the UI of the player. The non one-to-one operation of the scroll wheel of previous FiiO X-series players didn’t really bother me before, but it’s nice to finally have the on-screen actions exactly correspond to each physical movement of the wheel.
 
 
Another thing that I want to mention is the screen of the X5ii. Wow, it’s a nice screen, especially considering the price point that it’s selling at and all of the other stuff crammed into its chassis. Compared to the X3ii’s screen, text is sharper, colors are much more vibrant, contrast is greatly improved, and viewing angles are much larger. Also, it’s much brighter and much more legible in sunlight (so it’s actually usable outdoors) compared to the X3ii, which was pretty much unusable even at max brightness in a lot of outdoor conditions. Honestly, I think the screen is one of the big reasons why FiiO charges more for the X5ii compared to the X3ii, because it’s that much better.
 
 
 
A quick note on USB DAC functionality – it works flawlessly, and I couldn’t find any bugs or glitches with the X5ii when using it as such on Windows 7/8/8.1 (which I can’t say the same for the X3ii). And FiiO has now included a detailed but easy-to-read instruction guide on how to set up the driver and even DSD playback on Windows when you download the driver. Nice, FiiO!
 
Finally, I wanted to quickly mention battery life. I’ll just say that the X5ii lasted about nine hours driving my modded Fostex T50RP (a bit of a difficult headphone to drive) at a volume of 55/120 on high gain. This was with the X5ii playing a mix of CD quality audio, high-resolution PCM (24 bit 48 kHz files and above) and even DSD. I would say that’s not bad, considering the greater voltage swing capabilities under high gain mode.
 
Sound Quality
 
Tl;dr: The X5ii’s neutral signature allows it to pair well with a variety of sound signatures. The X5ii drives lots of full-sized headphones with authority, even when compared to desktop equipment. There’s not a big difference in sound between the high and low gain modes. While the X5ii does well against its little brother, the X3ii, and even against some desktop units, the X3ii offers much of the X5ii’s sound quality for a lower price, which kind of diminishes the X5ii’s value.
 
Now here’s the part that everybody is interested in. How does the X5ii sound?
 
Before I go on, I would like to mention that I primarily used the following headphones to evaluate the X5ii: Klipsch Image X10, Sennheiser HD598 and HD700, HiFiMAN HE-400i, and Fostex T50RP (self-modded).
 
Overall, tonally I would say that the X5ii is extremely similar to the X3ii, if not identical. That is, it has a very neutral sound signature, with perhaps a (very) slight dark tilt. To me, this allows the X5ii to pair well with a variety of headphone sound signatures. For example, the X5ii’s neutral character allows me to enjoy warmer sounding IEMs and headphones like my Klipsch Image X10 and my self-modded Fostex T50RP (which I purposely tuned to be warmer) without overly suffocating me with warmth. The very slight dark tilt also allows me to enjoy brighter headphones such as the HD700, which manages to sound very clear without being very fatiguing on the X5ii. Of course, the neutral nature of the X5ii also allows listeners to enjoy the relatively neutral HD598 and the HE-400i as they are.
 
Soundstage is of medium width – it’s not the biggest soundstage out there, but it isn’t exactly small. The X5ii also has good depth and layering to its soundstage. Imaging and separation is also done well too, so that one can clearly distinguish where sounds are coming from since they aren’t all mashed together. The X5ii also has pretty good detail retrieval, and even the most complex of music never sounds blurred or smeared together on this player.
 
One strength of the FiiO X5ii is that it can drive most full-size headphones without much problem, even when compared to full-sized desktop units. It had no problem whatsoever powering my Klipsch X10 or Sennheiser HD598, nor did it have any problems powering my Heiman HE-400i or Sennheiser HD700. Heck, it didn’t really have too much problems powering my modded Fostex T50RP or even the HiFiMAN HE1000 beta unit. The latter was especially surprising, since the HE1000 is a relatively power hungry beast, but the X5ii actually made the HE1000 quite enjoyable to listen to (though obviously the headphone didn’t sound its best here).
 
High Gain vs. Low Gain
 
An interesting feature of the X5ii is that the low and high gain modes don’t only affect the gain of the volume – it also toggles between different voltage swing modes, so that in low gain there is a lower voltage swing range to save power, and in high gain there is a larger voltage swing range to drive more power-hungry headphones but also consumes more power in the process.
 
While FiiO says that in high gain mode the voltage swing range is 40% greater than in low gain mode, does this really make a difference in how a headphone or in-ear monitor sounds?
 
After volume-matching between the different gain modes using an SPL meter with C-weighting, to be honest the differences are extremely subtle. In fact, I would say that with most types of music (with the exception of classical, as we’ll see below), one will be hard-pressed to find any meaningful differences in direct comparisons.
 
For example, with the 35 ohm impedance planar magnetic HiFiMAN HE-400i, under high gain mode with non-classical music, I thought I heard that drums to perhaps have a bit more impact, the bass to seem to be slightly more controlled, and perhaps the more minor elements in the mix to be slightly more defined and separated from the rest of the music. However, with classical or orchestral music, I heard a bigger difference. There seemed to a sense of greater effortlessness to the sound with mids and highs being slightly less raspy and grainy, subtle nuances in changes in the volume were more obvious, and the sound seemed to be a bit more airy in that I could hear more of the room reverb in the recording. For example, the sound string instruments such as the violin and erhu seemed to reverberate more distinctly in the air with high gain mode.
 
With the 150 ohm dynamic Sennheiser HD700, I pretty much heard the same subtle differences between high and low gain mode. However, there was a subtle, but audible difference to its bass presentation between the two different gain modes no matter which type of music I listened to. While the HD700’s bass did not necessarily increase, the bass seemed to go deeper and hit harder under high gain mode. But again, this wasn’t a huge difference and did not fundamentally change the nature of the headphone.
 
Overall, the high gain mode to my ears does sound a bit better, but you really wouldn’t be missing much if you choose to listen in low gain mode as opposed to high gain mode.
 
Comparisons to other audio gear
 
Note: All of the following comparisons were done under volume matching with a C-weighted SPL meter.
 
Vs. the FiiO X3ii
 
How does the X5ii’s little brother fare against it? Quite well, in fact.
 
Before I go further, I listened to the X5ii’s high gain mode and the X3ii’s low gain mode (because I could not hear a single difference between the X3ii’s high and low gain modes).
 
The X5ii, compared to the X3ii, has more refined and smoother edges to its notes. The X5ii is slightly more detailed, though the greater perceived detail is more due to the blacker background (of which I explain more below) The X5ii also has more emphasis on the sub-bass rather than the mid-bass as opposed to the X3ii, as well as the bass being more solid, coherent, and overall of better quality than with the X3ii.
 
In regards to soundstage, while the X5ii has a slightly larger soundstage, the depth between the two FiiO players is really about the same – I could not detect a difference in the latter aspect.
 
One of the biggest differences between the X5ii and the X3ii is that the X5ii has a blacker background. This in turn affects lots of parts to the sound. With a blacker background, I find that not only does everything sound a bit clearer, there is better separation on the X5ii so every instrument (and vocals) comes through more clearly and distinctly in the mix compared to the X3ii. With better separation, the X5ii also seems to have a bit more accurate imaging and slightly layering imaging capabilities. That is, with each sound more separated from each other, you are better able to perceive where the sounds are coming from horizontally and how far or close each sound in the music is from you. On the X3ii, occasionally instruments will sound like they’re on top of each other, while I find this not to be the case with the X5ii.
 
Another big difference between the two FiiO DAPs is that the X5ii is much better able to drive power hungry headphones. However, this isn’t as big of a difference you might think it to be. This is because I honestly could not say that the X5ii sounded like it drove the Klipsch X10, Sennheiser HD598 and HD700, or even the HiFiMAN HE-400i with any more authority than the X3ii. However, there was a pronounced difference between the X5ii and the X3ii when powering the modded Fostex T50RP or the stock HiFiMAN HE1000 beta unit. With the modded T50RP, while the X3ii slightly sounded underpowered with slightly grainy mids and highs, the X5ii did not sound underpowered at all. With the HE1000, there was a huge difference in that while the X3ii definitely sounded underpowered with grainy mids and highs as well has only producing a small soundstage, the X5ii eliminated this graininess to the higher frequency sounds and produced a much larger soundstage. (I find that the HE1000’s soundstage tends to shrink in when underpowered.) But how many people are actually going to buy a DAP like the X5ii and use it to drive something crazy like the HE1000? That is why I say that the difference between the X5ii and the X3ii in terms of driving power is not as big as you might think my words would imply, since the difference is only really apparent with very power hungry headphones.
 
Overall, going along with the general theme of the previous paragraph, the X5ii definitely is a step up in terms of sound quality compared to the X3ii, but it’s not a night and day difference and is somewhat subtle. I know that I’ve described what seems to be a lot of upgrades in the sound quality of the X5ii compared to the X3ii – but I will say that I’ve actually had to listen to the two players in direct comparison very closely for quite a while before I could actually articulate these subtle differences. Basically, while these differences will be apparent to the most sensitive audiophiles, most people are going to be hard-pressed to tell any big differences between the sound of the X5ii and the X3ii, especially if they compare the two only for several minutes. Admittedly, this does kind of diminish the X5ii’s value relative to the X3ii – but this is not to say that the X5ii sounds bad or doesn’t even sound better than the X3ii at all.
 
Vs. the Aune T1 mk1
 
How does the X5ii compare to a desktop unit? Specifically, the Aune T1 mk1 which for the purposes of this evaluation I’ve outfitted it with an upgraded Amperex Orange Globe (OG) tube? (The T1 mk1 and the OG tube altogether cost me about $200.)
 
In short, to my ears the X5ii sounds better than the T1 even with the upgraded OG tube.
 
The X5ii and the Aune T1 mk1 with the OG tube are comparable in soundstage size – both in width and depth. Both also do well and are equally good in layering, imaging, and separation capabilities. Surprisingly enough, even though Aune claims the T1 mk1 can deliver 1000mW of power into 32 ohms (compared to the X5ii’s 245mW into 32 ohms), I felt that the two drove headphones such as the HE-400i, HD700, and even the T50RP with equal authority.
 
While I felt that the X5ii and the T1 with the OG tube were equals in terms of the aspects above, I also felt that there were a number of areas in which the X5ii was better. The X5ii seemed to have smoother, more refined notes to its sound compared to the T1 with the OG tube. I could also hear the “airiness” and more reverb of the sound in the recording environment more easily with the X5ii. The X5ii also not only had more bass, it also had the deeper and more detailed and texture bass compared to the T1 with the OG tube.
 
Overall, while I felt that the X5ii and the T1 were comparable in a number of areas, the X5ii wasn’t worse in any single area and in fact bettered the T1 in some parts of its sound. So to me, the X5ii is the clear winner of this comparison.
 
 
For whom is this player good for?
 
Tl;dr: The X5ii is good for those who want the best as of now from FiiO, as well as those who have hard-to-drive headphones. But many others might want to gravitate towards the X3ii instead.
 
The X5ii should be considered by anybody who’s looking for good-sounding, mid-priced DAP due to its fantastic build quality and ergonomics as well as its sound quality. Also, anybody looking for a reasonably priced portable source looking to drive more power hungry full-sized headphones should also give the X5ii a serious look. I would also say that the X5ii is good for anybody looking to minimize their collection of audio equipment by having just one source for both home and on-the-go usage, since the X5ii is able to drive a wide variety of headphones and IEMs very competently and has flawless USB DAC functionality.
 
However, the X5ii’s own worst enemy is its own little brother, the X3ii. For anybody who is not extremely sensitive to how their source sounds, doesn’t really care too much about the screen, like the slightly smaller size of the X3ii, doesn't need/doesn't care about the extra features of the X5ii (such as the two micro SD slots and not having a 5800 song limit), and/or has easier to drive headphones, they should probably look at getting the X3ii, since that offers much of the sound quality of the X5ii for a lower price.
 
Conclusion
 
Tl;dr: The X5ii is a great sound player that’s definitely worth its asking price. However, many people (and their wallet) may be served better by the X3ii.
 
Overall, I feel that the X5ii is a great-sounding DAP that is especially useful for difficult to drive headphones and physically feels as if it’s worth every cent of its asking price. It’s a great portable music player.
 
However, for those who don’t necessarily want the best sound but still want great sound, they might be better off with the X3ii, which I find to be fairly close in terms of sound quality to the X5ii but for a decently lower price (and it’s a bit smaller too, which helps portability though the X5ii itself isn’t huge). But for anybody wanting the best of FiiO, the X5ii is definitely the way to go.
 
While the X5ii is overall a great DAP with no real flaws, the fact that the X3ii exists and offers an amazing value leads me to give the X5ii 4 out of 5 stars. (Add another star to that if you really care about the better screen, the two micro SD card slots, and the greater than 5800 song limit because there are no real big flaws to the X5ii.) Don’t get me wrong, the X5ii is still a great player and is still a good value – it’s just that for most, the X3ii may be the even better value.
 
Thanks for reading my review of the X5ii!
 

Table of Contents

• Introduction
• Usability and Ergonomics
• Sound Quality
  • How does it pair with certain headphones?
  • How does it compare to other audio gear?
• For whom is this player good for?
• Conclusion

 
(Before I even begin the disclaimer, I want to warn and apologize to the reader that my review will be long. Thus, you can click on the table of contents above to jump to whichever section you want. I’ll also include a summary tl;dr summary at the beginning of each section.)  
 
Introduction
 
Tl;dr: Just stating FiiO lent me the unit and some of my personal history.
 
Before I begin my review, I would like to thank Joe Bloggs and the rest of the team at FiiO for providing an X3 2^nd gen loan unit for 10 days to review. FiiO has not paid me whatsoever in the making of this review, and is only asking for my honest opinion. I actually think this says a lot about them – they’re confident that they’ve made a good product, and don’t need to pay people off for them to say good things.
 
And you know what, they absolutely have every reason to think so.
 
Before I get into why the X3 2^nd gen is a great product, I’d like to explain a bit of my audiophile background and how it specifically relates to FiiO. I actually began my journey with FiiO – their E7 portable DAC/amp combo was the first real piece of audio gear (besides headphones) that I bought. I thought that it sounded so good that soon not long after their E17 came out, I bought that as well and used it for the next year or so. However, after listening to other people’s gear, I started to notice what was missing from my FiiO gear and how my tastes in sound signature was changing. My E17 started to sound a bit too dark for my tastes. This was what caused me to stay away from FiiO entirely for a while.
Fast forward a year or two later. I wanted a good-sounding portable device because my smartphone just wasn’t cutting it. So I started to look at DAPs, and specifically noticed that FiiO had branched into there. I still had a soft spot for FiiO because they were my introduction into the audiophile world, so I thought “why not?” and sought out to somehow audition the X5. And when I did – I was impressed. FiiO had come a long way in making their stuff sound so much better. So when I saw that FiiO was planning a tour for the new X3, I immediately jumped at the chance.
 
Needless to say, after my experience with the X5 I had high expectations for the X3.
 
 
 
 
Usability and Ergonomics
 
Tl;dr: Great ergonomics and responsive UI. Good battery life. Screen is hard to read under sunlight. Some glitches with the firmware and USB DAC driver.
 
I’m not going to spend too much time in this section, mainly because the many other reviews have already done an excellent job of covering these aspects. However, I will comment on several things that jumped out to me.
First are the in-line controls. They pretty much worked flawlessly as advertised and without much delay (like half a second after my button presses), using my Klipsch ProMedia In-Ear, which only has a single button to the mic. These controls are very convenient for whomever happens to have such an IEM or headphone with these controls, as it literally allows you to do all of the playing functions without ever taking the X3 out of your pocket, or bag, or whatever have you.
 
Second is the responsive UI. The X3 pretty much flies through its menus very quickly without hiccups. Playing even DSD files doesn’t elicit much, if at all, of a slowdown from the X3. And I remember the X5, when I auditioned it, sometimes could not keep up with the user changing the volume too quickly using the scroll wheel (this may have been changed with later firmware). Not so with the X3 – it always changed the volume as fast as I could spin the wheel. Also, the “deep hibernation” mode works flawlessly – it’s really convenient having the player pretty much boot up instantly after putting itself into a power conservation mode. And even if you don’t use that feature, I find that a full boot-up of the X3 2^nd gen doesn’t take all that long – certainly a lot faster than the Android smartphones that I’m used to.
 
Third are the great ergonomics and feel in the hand. For anybody who is wondering how on earth does putting the power button and the volume buttons on the same side and relatively close to each other work, FiiO has got you covered. One, the power button is spaced out enough so that it sits by its lonesome so that one is not likely to mistake it for the volume buttons. Two, the power button is nearly flush to the body of the X3 2^nd gen while the volume buttons are significantly raised up. I find it hard to believe that people will mistake the power and volume buttons with these design considerations. I also find that indicating which button is the volume up button by putting a slight protruding point on it is a nice touch.
 
 
However, not all is good with the X3 2^nd gen here. The major thing that I’m not happy about is that the volume buttons stop working under certain conditions. (This isn’t fixed as of firmware version 1.1.) I’m not sure how to exactly cause this bug, but under certain conditions the volume buttons will simply just stop working, or, in other cases, allow you to only change the volume for a few steps before it stops working. A reboot of the player solves this, and holding down the center button will always allow you to change the volume with the scroll wheel, but it is annoying.
 
Also, while the screen is actually better than I thought because it’s reasonably sharp, it lacks contrast and viewing angles aren’t great. This doesn’t really matter because I’m not constantly looking at the screen of a DAP. But the fact that even with max brightness, I can’t really see the screen even under moderate sunlight does matter.
 
A quick word on the USB DAC functionality – it pretty much works flawlessly, with the exception of a bug that I found using Windows 8.1. Setting up the drivers was not difficult and even setting up DSD playback in Foobar2000 was not too difficult. However, there is a bug to the drivers that I can consistently reproduce – if you try playing DSD using Foobar2000 in actual DSD mode, and then attempt to switch to playing the same DSD track except converting it to 176.4 kHz PCM, the music will start to dropout and stutter. The only way to really solve this is to unplug the X3 2^nd gen from the USB port and then plug it back in. This is not a huge deal for most users, but I thought I should mention it.
 
As for battery life, I’ll just mention that I clocked the X3 2^nd gen being able to run nine hours. This was with it playing a mix of CD quality, high-resolution PCM (24 bit 48 kHz files and above), and DSD files, driving my 35 ohm impedance HiFiMAN HE-400i on low gain at a volume of 73/120. Seems pretty decent to me, no?
 
Sound Quality
 
Tl;dr: The X3’s overall sound signature allows it to pair well with lots of different headphones. It doesn’t sound underpowered even with full size headphones. For some headphones, the sound on the X3 is good as it gets short of using expensive desktop equipment. The X3 compares well to lots of portable devices and even does well against desktop equipment in its price range.
 
We now get to the juicy part of the review. How does the X3 2^nd gen sound like?
 
I would classify the sound signature as very neutral, with perhaps a (very) slight dark tilt. In my opinion, the neutral sound signature allows it to pair very well with warmer sounding headphones and IEMs. The slight dark tilt also allows brighter sounding headphones to be less fatiguing without taking away their fundamental character (I like my sparkle in the treble, so this is good for me). To me, FiiO has somehow managed to infuse the X3 2^nd gen with a sound signature that pairs well with just about any common sound signature you can find in a pair of headphones/IEMs.
 
Soundstage is of about medium width, and with really good depth that allows headphones with good layering capabilities to shine (it’s about as good as a $200 product can get). Imaging is also pretty good on the unit – this is due to the previously-mentioned good depth, and because of pretty decent separation between instruments. There’s no smearing at all between instruments when playing complex music on the X3 2^nd gen, and even slight details cleanly come through.
 
I also find the X3 2^nd gen to have a somewhat aggressive kind of sound, and not laid-back. By this, I mean that the X3 2^nd gen really emphasizes the differences in dynamic range, and somewhat pushes the music to be in front of you. So the music is punchy and is somewhat forward on the X3 2^nd gen. But it’s not to the point where I would find the X3 2^nd gen to be fatiguing to listen to for long periods of time.
 
How does it pair with certain headphones?
 
I used the following headphones/IEMs to test out the X3 2^nd gen: Klipsch Image X10, Sennheiser HD598, Sennheiser HD700, HiFiMAN HE-400i, and Fostex T50RP (self-modded).
 
With the Image X10:
 
 
The X3 2^nd gen really nicely brings out the body in the bass of the Image X10. But it doesn’t do this at the expense of the mids and treble – which I find the X3 2^nd gen to also bring out nicely without being drowned out by the bass, and handles with finesse. This is an example of how I mentioned earlier that the neutral sound signature of the X3 2^nd gen pairs well with warmer sounding IEMs like the X10. The X10 is not among the most highly sensitive IEMs, and will definitely respond to good amping. The X3 2^nd gen provides enough clean power that I can definitely hear the differences between it and other portable music devices when using the X10 – mainly, this is by giving the mids and trebles a smoother but yet more defined character that lesser audio gear can’t do to my X10. In fact, using the X3 2^nd gen I’m not sure how much better the X10 can sound without resorting to much more expensive desktop setups that cost much more than the X10 itself (yes, I have actually listened to the X10 on my much more expensive desktop gear).
 
With the HD598:
 
 
In my opinion, the X3 2^nd gen pairs wonderfully with the HD598. I think the HD598 has a slightly bright character, and so the very slightly dark but overall neutral nature of the X3 2^nd gen allows the mids and highs of the HD598 to shine without it becoming fatiguing at all). The X3 2^nd gen is definitely not underpowered when it comes to driving the HD598 – there’s no real graininess to the mids and highs, and really allows music with great dynamic range to come through powerfully. While the medium width soundstage of the X3 2^nd gen doesn’t allow to HD598 to fully present that expansive soundstage, the great depth of the X3 2^nd gen allows the layering capabilities of the HD598 to really shine. The very good imaging capabilities of the HD598 also shine with the X3 2^nd gen since the DAP is able to do a great job at separating instruments and putting them together in a coherent soundstage. The only thing that I may even have a complaint about is that the X3 2^nd gen doesn’t fully bring out the last bit of bass from the HD598, but again that’s only possible with expensive desktop equipment that costs much more than the headphone itself. In fact, that’s a pretty good summary of how the HD598 sounds on the X3 2^nd gen – it’s not going to get much better than this unless you use something crazy expensive.
 
With the HD700:
 
 
How well does the X3 2^nd gen drive the HD700, which costs much more than the DAP itself and being rated at 150 ohms is the limit of what the X3 2^nd gen is rated for? Surprisingly well, in fact. The slightly dark character of the X3’s sound really takes the edge off of the HD700’s treble and makes it a far less fatiguing listen – but it won’t transform the HD700 into an entirely different headphone. Bass and dynamic range also come nicely through the X3 2^nd gen, but one can only still squeeze that last bit of depth and body to the bass using desktop equipment. Mids and highs also come through quite nicely, though it lacks that last bit of extension and refinement that again, only much more expensive equipment can provide. Details are also plentiful with the X3/HD700 combo. The soundstage width and depth of the HD700 through the X3 2^nd gen is definitely reduced compared to desktop gear, but is still good enough to allow the excellent imaging, layering, and coherency of the HD700’s soundstage to come through. Overall, I am pretty happy with the X3 2^nd gen powering the HD700 despite having heard how it sounds on more expensive gear.
 
With the HiFiMAN HE-400i:
 
 
We have here a planar magnetic headphone, though it is one the easier ones to drive. So how does the X3 2^nd gen fare with the HE-400i? Actually pretty dang well, I’d say. While the bass of the 400i with the X3 2^nd gen doesn’t hit as deep as with a desktop amplifier, it still has plenty of body and sounds very satisfying. The neutral nature of the X3 2^nd gen also allows the great mids and highs of the 400i to shine, but they are a bit unrefined compared to more expensive desktop equipment. Vocals especially sound a tiny bit raspy and bright compared to the best I’ve heard the 400i in – but it’s far from being unsatisfying. The great depth and imaging (due to the good separation and decently wide sound stage the X3 gives the headphone) of the 400i is apparent with paired with the X3 2^nd gen – a plus in my book. All in all, the X3 2^nd gen doesn’t really sound underpowered with the 400i – especially if you don’t compare it to much more expensive equipment. This pairing truly is a satisfying experience, even though I usually use much more expensive gear to drive the HE-400i.
 
With the modded Fostex T50RP:
 
 
To be honest, I wasn’t expecting much out of this combo – how could a portable device be able to really drive the T50RP, when modded craves lots of power? However, the X3 2^nd gen pleasantly surprised me by pairing relatively well to the T50RP. The mids and highs were definitely a bit grainy compared to listening on higher-end desktop equipment but not so much as to suggest that the T50RP was woefully underpowered, and bass seemed a bit boomy by being able to only draw out the mid-bass and not as much of the sub-bass. However, the X3 2^nd gen still allowed the Fostex to retain its good imaging and separation, and didn’t really make the soundstage any smaller than it already is. And like with the Klipsch Image X10, the X3’s neutral signature paired well with the darker nature of my modded T50RP so that the sound had plenty of body and lower range emphasis but retained just enough sparkle in the treble to make for a captivating listening experience.
 
If what I just said makes it sound like the modded Fostex T50RP sounds like total crap on the X3 2^nd gen, it doesn’t. To really convey how impressed I am that the $200 X3 2^nd gen can drive the T50RP, let me offer the following anecdote: I’ve actually listened to my modded T50RP through the Sony NWZ-ZX2 and AK100ii. I distinctly remember feeling that both of those DAPs were underpowered because they made the mids and highs on the T50RP sound somewhat hazy and grainy. The X3 2^nd gen from my experience does not suffer from this. Enough said.
 
How does it compare to other audio gear?
 
These are the other amp and DACs that I had on hand to compare to the X3 2^nd gen: Sony Walkman NWZ-S716F, HTC One M7, FiiO E17, and Aune T1 mk1.
 
Vs. the Sony Walkman NWZ-S716F (tiny little DAP)
 
 
First off, let’s get this out of the way: the X3 2^nd gen simply has a lot more driving power than the tiny Walkman. The Walkman somewhat struggles at making the HD598 sound really good while the X3 makes even the modded T50RP sound not half bad.
 
Thus, my comparisons between the X3 and the Walkman are solely based on using my Klipsch X10. Overall, the sound on the Walkman is more hazy and blurred. For example, drum cymbal hits are “splashy” and all smeared together on the Walkman, while they are clearly distinct and sharp without going overboard on the X3 2^nd gen. Imaging is better, and the soundstage is much better on the X3 – there’s really no contest here. One can pick out the ambient cues and listen to the ambience of the recording room much better on the X3. Vocals are smoother and more defined on the X3. The bass on the X3 actually seems to punch less hard than on the Walkman, but in return the X3 provides bass that has more body and is more textured.
 
Vs. the HTC One M7 (high-end, very good audio quality smartphone)
 
 
Surprisingly, I would say that the M7 and the X3 have a similar amount of driving power – they both can drive cans like the X10 and the HD598 fine, and do a decent (but not the best) job at driving the HD700, HE-400i, and the modded T50RP. As for sound signature, the X3 is slightly brighter than the M7. However, despite being brighter, I find that the X3 somehow gives everything from vocals to guitars that extra bit of weight that makes it sound that more realistic than the M7. The level of detail presented between the two devices is surprisingly about the same – but this is not a knock to the X3, since I find the M7 to actually have a good amount of detail. The mids and treble on the M7 are perhaps a bit fuzzier and more unrefined than the X3, but it is a noticeable difference. The X3 also seems to be able to better portray dynamic range than the M7 – which gives the X3 the edge in classical music. The X3 also has a blacker background and better separation of instruments than the M7. Soundstage width between the two devices is about the same, but the much greater depth of the X3’s soundstage really makes the M7 sound flat soundstage-wise. Honestly, I’m impressed at how well the HTC One M7 stacks up against the X3. But make no mistake, the things that are better on the X3 really add up to make listening to it a better experience.
 
Vs. the FiiO E17 (portable DAC/amp combo that the first gen X3 is based on)
 
 
While I don’t exactly have a first generation X3 on hand to listen to, I do have an E17, which the first gen X3 is pretty much identical to in terms of hardware and supposedly even sound.
 
Right off the bat, I can tell that the new X3 has much more treble extension and presents much more detail than the E17 does. The E17’s mids and treble are very smoothed over and really lacking in detail compared to the X3. Vocals especially sound much better on the new X3 than on the E17 and is quite noticeable. Not only are vocals on the X3 more detailed, but I can also hear the slight differences in intonations and volume changes in a person’s voice much more easily and the vocals really come to life compared to in the E17, whose vocals sound lifeless in comparison. As suggested by what I just said, the E17 definitely has a warmer sound than the new X3, though it isn’t excessively warm. The E17 has a slight mid-bass emphasis which simply isn’t there on the X3 2^nd gen – the latter of which is more to my taste.
 
While soundstage width on the X3 and the E17 are comparable, depth is noticeably better on the X3. Things just simply feel closer to you on the E17. Background details in the mix of the music are more apparent and imaging is better on the X3 due to a blacker background and better separation.
 
One thing that the E17 has that the X3 doesn’t is some kind of weird “glare” at certain frequencies to the sound. Some things sound artificially louder and “brightened” than what sounds natural to me, as if FiiO were trying to make it sound like there is more detail than what there actually is due to the really smoothed out top end of the E17. For example, brass instruments sound like they should on the X3, but for some reason are brighter and somewhat harsher than what should be right to me on the E17.
 
Overall, I think the X3 2^nd gen is a pretty substantial jump in audio quality compared to the E17.
 
A quick note comparing the amps of the X3 2^nd gen and the E17 – to be honest, I think they’re mostly comparable in terms of driving power and quality. I think this means that the X3 2^nd gen is not really going to benefit from external amplification unless you get a really powerful and clean amp, given that the E17 amp is not that weak.
 
Vs. Aune T1 mk1 (desktop DAC/amp combo for about the same price as the X3)
 
The DAC sections: I compared the DAC parts of the Aune T1 mk1 and the X3 2^nd gen with both using the Aune T1 headphone amp. With the stock EH6922 tube, I actually feel that the X3’s DAC section is better than that of the T1. With the EH6922 tube, the T1 actually sounds a bit veiled and sounds lacking in detail compared to the X3.  You hear much more airiness and notice tiny ambient cues much better with the X3 DAC. The soundstage with the X3 DAC is definitely deeper, while the width is comparable. Imaging and layering are much more precise on the X3 DAC than the T1 with the stock tube. For some reason, the bass on the X3 also hits harder and deeper. Overall, the X3’s DAC to my ears sounds better than the T1 with the stock tube.
 
With the Aune T1 upgraded to an Amperex Orange Globe (OG) tube, the T1 and the X3 DACs are much more comparable. In fact, I would say they’re about the same quality, and that preference will dictate which one you prefer. The T1 with the OG tube does not sound veiled at all compared to the X3 – to me, they’re equally clear.  Soundstage width and depth are pretty much about the same between the two DACs. Imaging is equally clear and precise between the X3 2^nd gen and the T1 with the OG tube. The only real differences that I notice are that the T1 with the OG tube seems to be slightly warmer than the X3 2^nd gen, and that the X3 presents a more aggressive and dynamic sound while the T1 OG tube combo sounds a bit more laid-back.
 
The amp sections: For this comparison, I compared using the X3 DAC’s section paired with its own built-in headphone amp and paired with the T1’s amp. The X3’s headphone amp presents a smaller soundstage (by a fair amount) in terms of both width and depth. The X3’s amp also seems to be somewhat warmer and “softer” than the T1 amp – for example, brass instruments seem to be “sharper” and a tiny bit more shrill sounding on the T1’s headphone amp. The T1 amp sounds more powerful because it sounds more “effortless” at driving more power hungry headphones such as the T50RP, HE-400i, and the HD700, as in the mids and highs are less etched and grainy. (Also, the T1’s amp can extract more and deeper bass from the aforementioned 3 headphones.)  However, the difference is not as big as you think (and is pretty much nonexistent with easier to drive full size headphones like the HD598).
 
Also, the X3 has an advantage in driving IEMs due to its low output impedance. The Aune T1 mk1 I believe has an output impedance of 10 ohms, which does weird things to the frequency response of my Klipsch X10 by making the bass too boomy and making it too bright in certain parts of the treble. I have none of these problems with the X3.
 
 
 
For whom is this player good for?
 
Tl;dr: The X3 2^nd gen is not only good for anybody looking for a DAP $200 or less, but also for anybody who wants excellent sound for their computer in the same price range.
 
I would argue that the X3 2^nd gen is not only right for people who are looking for a reasonably priced DAP $200 and under, but also for any audio enthusiast who wants have a nice sounding setup, DAC and amp and all, for $200 or less. The X3 has decent battery life, a responsive and well thought-out UI, and is portable enough to make it a strong contender for anybody looking for a DAP in this price range. On the other hand, the X3 2^nd gen also has the handy USB DAC function which works pretty well and its sound quality is comparable to the best of the $200 or less desktop setups (based on my experience comparing to the Aune T1, itself which many think compares favorably to other popular desktop units in that price range such as the Schiit Modi/Magni combo). The DAC is also good enough that I feel somebody could still keep using it down the line and do justice to an upgraded portable or desktop amp. The X3 is a great choice for anybody who wants something that they can not only take with them on the go, but also plug into their computer and listen to at home without feeling they have made any real compromises.
 
Conclusion
 
Tl;dr: The X3 2^nd gen is a fantastic value. I highly recommend it.
 
Has FiiO met my high expectations after I was impressed with their X5? Definitely yes, and they probably exceeded them by putting the amount of sound quality they did into such a small nice-feeling package and at that price point too. I know by now that I’m just gushing about how good the X3 2^nd gen is, and you might be wondering if I really hadn’t been paid by FiiO to say all these things despite my disclaimer at the beginning. I really am that impressed, and judging by the other reviews, I don’t think I’m the only one.
 
Overall, I really want to give the X3 2^nd gen a 5 out of 5 because of its incredible value, but since there are still some very minor problems (notably the volume problem and the USB DAC driver bugs) I noticed, I’m going to give it 4.5 out of 5. The X3 2^nd gen comes highly recommended.
 
This was my first review, and I know that it may not be perfect. If anybody has some suggestions on how to make my future reviews better (such as the length being too long, etc.) please feel free to let me know.