FiiO Kilimanjaro 2 (E11K) Portable Headphone Amplifier


New Head-Fier

Disclaimer: I am not affiliated to Fiio in any way and do not benefit monetarily or in any other form for writing this review. I purchased this in-ear monitor with my own resources and I am simply giving my honest review of the product!

Review by: “Charlie” from The Little Audiophile

Fiio. A company that has really made a name for themselves in the audio industry. Their X-series of DAPs has been making big waves in the audio world for their high quality players that does not cost a kidney and a liver. Fiio’s A-series of Amplifiers are again, known for their excellent price to performance ratio. Today I will review the Fiio A3, which is the company’s mid range portable headphone amplifier. With the MSRP of just under S$90, this amp delivers, just without the massive price tag.


The Fiio A3 features a 1,400mAh battery, rated for 16 hours, a Low and High gain setting and a nice Bass Boost function. It has a very low output impedance of <0.2 ohms and Fiio recommends pairing the Amp with headphones with impedance ranging from 16-150 ohms. I know… these are all just numbers and specs where you can read online. But I’ll explain more on these features throughout the course of the review.


Right. Firstly, lets talk about audio colouration when using this Amp. Luckily, the Fiio A3 is mostly neutral and transparent throughout the frequency range when Bass Boost is turned off. Which is good because an Amplifier’s main purpose is to deliver more power to the headphones and not modify the sound signature in any negative way.

Music sounds richer and more immersive even, when I use the Fiio A3 with Bass Boost on. The music seems to be more intimate, while soundstage on certain headphones, seem to expand. It is honestly hard to put in words what I am hearing. It is like tasting fresh milk when you have been drinking low fat milk all along, and now you don’t wanna go back. It is something like that…

Anyways, the Bass Boost function gives aoughly a 4dB increment in approximately the mid-bass region at 50Hz which as mentioned, helps in making the experience more immersive. It is good to note that this increase in bass does not muffle the mids, which in turn means that vocals remain clear even though the bass is emphasized. However with Bass Boost on, sound stage seems to narrow down a little.

Now, the A3 definitely isn’t the end game in the headphone amplifier market. It too has it’s downsides and to be fair, I’ll have to talk about the not-so-good parts of the Fiio A3. Here goes.

Bassy headphones suffer from very mild Static like/Distortion(y) sound in the low bass to low mid-bass region when Bass Boost is on and when listening on average volume with the dial turned to 6 and my source at 50% volume. I first noticed this when listening on my Massdrop x Nuforce EDC where the low and low mid-bass(es) sometimes sounded unstable and there was a little bit of growling-like noises.

The A3 does sometimes exhibit very soft static noises in between changing tracks that does not affect the music when it plays, but I think it is a good thing to note.

One last boo-boo about the A3 is channel imbalance on low volumes. When the dial is set under 2, the left channel is obviously louder than the right channel. However in it’s defense, I never actually listen on such low volumes anyway. With low gain, my volume dial is usually set within 5 to 7, depending on the track, ambient noise and headphone used. At such settings, the channels seem balanced enough.


As important as sound quality is, the user friendliness should not be forgone, such that the user would even bother using them. These are my thoughts on what I liked and disliked about this amplifier.

First off, I really liked the Analog dial that the A3 uses. It allows for a better control over listening volume.

Secondly, Fiio decided that changing the issued 6 rubber feet to 2 white translucent rubber pads is more feasible. This I wholeheartedly agree, considering that the Fiio A3 is a portable amplifier, and would be stacked with a phone, DAP or perhaps even a DAC most often. It prevents scratching of it’s “other half” and makes stacking so much easier.

Thirdly, I had wished for different coloured indicator lights to . Perhaps blinking red for charging, steady green for charged, steady blue for normal operation and steady red for errors instead of slow blinking, rapid blinking and steady blue for its status indicator.
Lastly, I had wished that Fiio used a 1/4 inch jack for output instead of a 3.5mm jack, just like the one that the iFi iCan Nano sports. It would open up that many more options as for headphone pairing. However with the compactness of the Fiio A3, a larger jack might not be possible and I might just be being nit-picky here.


I believe that the Fiio A3 is an excellent performer for its price range and comes with a limited, but well thought out set of accessories.

I have personally tried the Fiio A5 which comes in at a significantly higher price at $199 at the point of writing this review but I could not hear any significant improvements in sound over the A3 despite it’s better specifications. The iFi iCan Nano is another amplifier that I had the chance to audition, and yes, they definitely trump the Fiio A3 slightly in terms of audio clarity, but do bear in mind that the iCan Nano comes in at S$259, which is nearly three times the cost of the A3! I love the iCan Nano’s performance but I personally and most certainly cannot justify the price. It is without doubt good. But not like three times as good. I always keep this mentality before I make a purchase, that is “specs are just specs. In practice things are different. And that is what is most important.” For the average user or even the audio enthusiast, the A3 is very user friendly, extremely compact and very well built and it sounds awesome! The power output is adequate for most headphones up to 200 ohms to get to a decent listening level.

The Fiio A3 pairs very well with my Astell and Kern AK Jr and does really help liven up the bass region in my music. In closing, I believe the Fiio A3 might be the amplifier for you if you are looking for an amplifier with a excellent price to performance ratio and do not wish to bottleneck your “mid-fi” audio equipment.

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Pros: Transparency, build, value, battery life, output power, features vs cost
Cons: Curved shape, almost too much power for sensitive IEMs
For larger (1200x800) images, simply click any photo


When I first came to Head-Fi I was naturally curious about portable amps. When I got my first one (the old E7) I was blown away – the increase in clarity, details, soundstage! Then over time, as I read more, experimented more, and (more importantly) tested more, I can to realise that those benefits I was sure I heard, had mostly come about by simply turning the volume up.  And with the portable amps I was using, I wasn’t volume matching when comparing.  Once I actually started comparing objectively, most of the time those differences disappeared. Sure – there are times when you absolutely need an amp – like with the 320 ohm VE Zens, or if I want to drive my HD600s portable, and there isn’t enough volume. But for a long time with my portable listening, I stopped carrying a portable amp.
Then around Sept/Oct 2014, I worked with Fiio to set up a “Down Under tour” for their new X1 DAP, and as a bonus they also threw in their E11K amp. At the completion of the tour, I offered to buy both units from Fiio (and yes – I paid real money for them), and the last 12 months has given me a whole new perspective on portable amping, why you might want to use one, and why the budget prices E11K (A3) portable amp from Fiio should be considered.
By now, most Head-Fi members should know about the Fiio Electronics Company.  If you don’t, here’s a very short summary.
Fiio was first founded in 2007.  Their first offerings were some extremely low cost portable amplifiers – which were sometimes critiqued by some seasoned Head-Fiers as being low budget “toys”.  But Fiio has spent a lot of time with the community here, and continued to listen to their potential buyers, adopt our ideas, and grow their product range.  Today, their range includes DAPs, portable amps, portable dac/amps, desktop dac/amps, earphones, cables and other accessories.
Fiio’s products have followed a very simple formula since 2007 – affordable, stylish, well built, functional, measuring well, and most importantly sounding good.
The E11K (A3) portable amplifier that I’m reviewing today was purchased by me (direct from Fiio) at the end of the Australasian tour I organised.  I have no obligation to write this review, I am not affiliated to Fiio in any way, and this is my honest opinion of the E11K (A3).
(This is to give any readers a baseline for interpreting the review).
I'm a 48 year old music lover.  I don't say audiophile – I just love my music.  Over the last couple of years, I have slowly changed from cheaper listening set-ups to my current set-up.  I vary my listening from portables (Fiio X5ii, X3ii, LP5 and iPhone 5S) to my desk-top's set-up (PC > USB > iFi iDSD).  I also use a portable set-up at work – either X5ii/X3ii > HP, or PC > E17K > HP.  My main full sized headphones at the time of writing are the Beyer T1, Sennheiser HD600, and AKG K553.  Most of my portable listening is done with IEMs, and lately it has mainly been with the Dunu DN-2000J, Jays q-Jays and Alclair Curve2. A full list of the gear I have owned (past and present is listed in my Head-Fi profile).
I have very eclectic music tastes listening to a variety from classical/opera and jazz, to grunge and general rock.   I listen to a lot of blues, jazz, folk music, classic rock, indie and alternative rock.  I am particularly fond of female vocals.  I generally tend toward cans that are relatively neutral/balanced, but I do have a fondness for clarity, and suspect I might have slight ‘treble-head’ preferences.  I am not treble sensitive (at all), and in the past have really enjoyed headphones like the K701, SR325i, and of course the T1 and DT880.
I have extensively tested myself (abx) and I find aac256 or higher to be completely transparent.  I do use exclusively redbook 16/44.1 if space is not an issue.  All of my music is legally purchased (mostly CD – the rest FLAC purchased on-line).
I tend to be sceptical about audiophile ‘claims’, don’t generally believe in burn-in, have never heard a difference with different cables, and would rather test myself blind on perceived differences.  I am not a ‘golden eared listener’.  I suffer from mild tinnitus, and at 48, my hearing is less than perfect.
For the actual listening part of this review I used the E11K (A3) mainly with my X3ii or X1 DAP, and a little bit with the iPhone 5S. Observations about the E11k (A3) are taken from the past year I’ve owned it. This is a purely subjective review - my gear, my ears, and my experience.  Please take it all with a grain of salt - especially if it does not match your own experience.
  1. Although Fiio are in the process of rebranding/renaming their portable amp line from E series to A series, from this point I’m going it simply call it the E11K.  It’s just easier.
  2. Volume matching was done with a calibrated SPL meter and test tones (1 kHz) when required for comparison.
  3. Frequency response and distortion measurements were taken using a relatively cheap Startech USB soundcard (which measures pretty well – 0.012% THD and 0.024% THD+N – which was consistent at 300 Hz, 1 kHz and 6 kHz @ -3 dB volume as suggested by ARTA using loopback). I combined this with a licensed copy of the ARTA measuring suite. The soundcard has a calibration adjustment applied – so that it measures dead flat from 20 Hz to 20 kHz.
I thought I’d list (before I start with the review) what I would now look for in a portable amp. This is useful to remember when looking at my reasoning for scoring later in the review.
  1. Genuine portability
  2. Good battery life
  3. Clean, neutral signature
  4. Easy to use
  5. Low output impedance
  6. Reasonable output power – should be able to drive IEMs and earphones up to 300 ohms
  7. Good gain control
  8. Value for money
  1. Fiio E7, E11, GoVibe Porta Tube, Headstage Arrow 12HE 4G, Beyerdynamic A200p
  2. Current portable amps E11K, E17K, VE Runabout


The E11K arrived in Fiio’s retail packaging – a white, red and black box measuring 130 x 130 x 25mm. The front had a picture of the E11K, and the rear has some specs and other information in English and Chinese.
Retail box - front
Retail box - rear
Retail box - profile
Opening the outer retail box reveals an inner box with a foam cut-out (securely holding the E11K), and a secondary box for the accessories.  The accessories include:
  1. 6 stick-on feet
  2. 1 x 3.5-3.5 mm cable (Fiio’s L8 mini to mini)
  3. 2 rubber stacking bands
  4. A USB to mini-USB recharging cable
  5. Warranty and instructions
Inside the box E11K + accessory box
Cables - interconnect and USB charging

The entire package is practical, covering everything you initially need for the E11K.  Materials are all good quality. If there was one thing I’d change it would be ditching the silicone feet (they slide around on the body) and instead including one of their silicone stacking pads.
Manual and warranty envelope
Stacking bands
The Fiio E11K

The table below lists most of the relevant specifications for the E11K.
Output Impedance H/O
<0.2 ohm
Recommended Headphone Impedance Range
16-150 ohms
Max Output Power @ 16 ohm
450 mW
Max Output Power @ 32 ohm
270 mW
>108 dB
0.004% (1 kHz)
Frequency Response
20 Hz-20 kHz
-3.8 dB (L) / 11.7 dB (H)
Channel Imbalance
<0.3 dB
Max Output Current
92.6 mA
Max Output Voltage
8.67 Vp-p
91 x 56 x 13mm
Outer Material
Brushed Aluminium
Headphone Out
3.5 mm
Battery Capacity / Life
1400 mAh / ~ 16 hours
Recharge Time
4 hours
The E11K is rectangular shaped with slightly bevelled edges, and a slightly curved top side and under side. The main body is a solid machined block of aluminium. At one end is the Alps potentiometer – nicely nestled between two raised protective arms (so it’s more difficult to accidentally bump the pot), the high/low gain switch, and the on/off bass boost.
Front/top panel
Gain switch and better view of edge bevelling
Rear/bottom panel - ports

At the other end is the 3.5mm headphone out jack – still nice and firm after a year’s use, a blue LED (solid blue when on, flashing blue when charging), a micro USB charging port, and the line-in 3.5mm port. Overall the external build is really solid, and even after a year my unit has very few scratches or bumps. The curved surface feels good in the hand, but it is the one design error I think Fiio made with this amp. It’s simply not that well suited for stacking (and that is what a portable amp will be mainly used for after all). If you’re using other Fiio gear with it, then their stacking kits and silicone pads really help – but the curved surface wasn’t one of Fiio’s smartest choices in this case.
In use LED light
E11K charging - LED slowly pulses

Opening the unit up, it’s easy to see the curved one piece body, and also how compact and tidy the layout is. One thing I also noticed was that the underside is fitted with a shroud.  I guess this has two possible uses – as a guard against accidental static flashes from the board – but maybe also as an EMI shield.  Compared with the older E11 (which I used to own), I have had no problems with EMI (and with the old E11 this could be an issue).
Some may find it a bit strange that the ports are at the opposite end to the volume pot – but I actually (over time) have found it quite natural. The good thing about this configuration is that the volume pot, bass boost and gain switches are very easy to get at (no cables getting in the way).
Opening the E11K
Note the curved aluminium body
Battery and caps

Ports exposed
Underside has antistatic pad/shielding
Close up of the caps

So far I’ve noticed no heat build-up at all with the E11K.  Even after a couple of hours (driving my HD600s), it’s still cool to touch.
For output power the E11K uses the OPA1642 for preamp and the AD8397 as its power amplifier. Fiio rates the target headphone impedance as 16-150 ohm, and I think that maybe a lot of people see this and automatically assume this little unit can’t drive a headphone like the HD600 (300 ohm properly).
But as I do the final edit of this review, I’m sitting with the X3ii feeding the E11K, then into my HD600’s.  Volume on the pot is around 3/9 (low gain), and I’m getting a very comfortable 65-75 dB with minimal effort.  This is my usual listening level so I’m pretty content. Taking the HD600 off my head, and cranking to maximum volume gives me 90 dB peaks.  High gain would add another 15 dB to take that to 105 dB – more than you’d ever need.  And at no stage do the HD600 feel under driven.
E11K with HD600, VE Zen and DN-2000J
E11K with DN2000J
E11K and X1 (with stacking kit)
Note that although this series of photos shows E11K with Fiio X1, the X3iiw as actually used in testing

With a variety of headphones / earphones at my disposal, the test track “Sultans of Swing” by Dire Straits, and X3ii feeding E11K via line-out at low gain – these are the approx. volume settings to get to a comfortable listening level (for me) at around 70-75 dB on low gain:
  1. HD600 (300 ohm, 97 dB SPL) = ~ 3-3.5/9
  2. VE Zen earbuds (320 ohm, 106 dB SPL) = ~ 2.5-3/9
  3. Trinity Delta IEMs (16 ohm, 110 dB SPL) = ~ 2/9
  4. Dunu Titan1 IEMs (16 ohm, 90 dB SPL) = 2-2.5/9
  5. AKG K553 Pro (32 ohm, 114 dB SPL) = 2.5-3/9
  6. Dunu DN-2000J (8 ohm, 102 dB SPL) = 2/9
And for giggles because I can
  1. Beyerdynamic T1 (600 ohm, 102 dB SPL = ~ 4/9 (Not recommended though – sounds a little thin)
So you can see that the E11K has a heap of power on tap – far more than its recommended 16-150 ohm headphone range belies. Clearly Fiio are being safe with their recommendations. Even switching to my lower output iPhone 5S (at full volume emulating a line-out) into the E11K, and again pairing the HD600s, the E11K only needed a slight bump to around 4/p on the pot.
The E11K couldn’t be much simpler to learn to use.  Simply plug your source into one socket, headphones into the other, press play on the source, and adjust the volume on the pot of the E11K to suit. The E11K has a really low output impedance (<0.2 ohm) so it should suit even the most sensitive earphones.
Using the bands to stack my iPhone 5S
iPhone 5S connected
E11K with X1 left and X3ii right
It does come with a bass boost (on/off) which I’ve measured as lifting the entire volume by about 1 dB, then lifting the bass between about 30-200 Hz with the main peak at 60-80 Hz – around 3.5 additional dB. It is noticeable but subtle (which I rather like). There is also a gain switch which raises the overall volume by ~ 15.5 dB.  The thing I like about this is that it a decent change in gain, and actually makes a difference – rather than just being put there as an afterthought.  Unsurprisingly, I really don’t use the gain toggle at all – unless it’s a low powered source, and a hard to drive load.  Nice to know it is there though.

Fiios stacker kit
X1 and E11K stacked
X1 with E11K stacked

Another feature which has been added from the original E11 is that this time you can charge the E11K and still listen at the same time.  Nice for those moments when battery is almost gone, you’re close to a power-point, and you still want to be listening. The other thing I really like about the E11K is simply having a proper pot to use.  It’s really nice being able to get to an ideal listening level with a very quick tweak of your fingers.  I’ve noticed virtually no imbalance either – even getting to the bottom of the pot.
Fiio rates the play time on a full charge at around 16 hours, recharge at around 4 hours, and for my use I’d suggest that time is pretty accurate. What I really like about the E11K though – and probably the reason I use both it and the E17K so often now – is that using it with the Fiio X1 or X3ii line-out extends battery life on both Fiios by at least 5 or so hours.  So if I was going to be on a long haul, or somewhere I simply needed extra life with my DAP, one of the two amps always comes with me.
I’m going to preface this section with a little critique I received a while ago (by PM), and my answer to it – so that you can understand why I don’t comment on some things, and why I do comment on others.  I was told my review on another amp was poor because I didn’t include sections on bass, mid-range, treble, sound-stage, imaging etc – yet referred to an amp as warm, full, or lean.
Now I can understand the reference to warm / full / lean – as they are very subjective terms, and whilst I’d like to avoid their use, they are invaluable to convey true meaning. Comparing my NFB-12 to the Aune X1S for example – the Audio-gd does sound richer and warmer.  It’s the nature of the DAC which is used.
But I choose not to comment on bass, mids, treble, and most definitely not sound-stage – simply because when we are talking about an amp – they shouldn’t be discussed.  An amp’s job is to amplify the signal with as low distortion as possible, and output as linear signal as possible.  If it is doing its job properly, there is no effect on bass, mids, or treble. And IME an amp does not affect soundstage (unless there is DSP or crossfeed in play) – that is solely the realm of the transducers and the actual recording.
So we have that out of the way how does the E11K perform sonically?
Channel matching within 03 dB
Normal signal (low), bass boost, and high gain
Close up of bass boost

The first thing I did was to check the linearity of the E11K, check its bass boost and its gain.  To do this I used a calibrated sound card (calibrated to measure completely flat), ARTA and a loopback. In the low gain and high gain frequency tests the E11K measured flat – amazingly flat. So what you are getting is an amazingly neutral amplification not adding or taking away anything. Channel balance throughout was also very good - approx than 0.3dB and for me that meant completely unnoticeable. The graph above is a close-up.
Next up was distortion measurements.  My USB soundcard measures (on loopback) THD at 0.010%-0.013% and THD+N at 0.020%-0.032% at pretty much -100 dB (this was with separate readings at 300 Hz, 1 kHz and 6 kHz).  When I added the E11K – I got exactly the same measurements with it in loopback – so the E11K is measuring lower than my USB sound card can measure.  It also means that the distortion and harmonic distortion are both inaudible. Fiio states measured THD at 0.004% on their lab equipment, and I have no reason at all to doubt this figure.
THD and THD+N @ 300 Hz
THD and THD+N @ 1 kHz
THD and THD+N @ 6 kHz

The last thing I measured was IMD, and again this was below the threshold of audibility, and again the E11K was measuring below the actual thresh-hold of the USB sound card. So what does this tell us?  Simply that the E11K supplies very linear, and very clean output.  Purely subjectively, it sounds very neutral – no added warmth or brightness I can discern.
IMD @ 300 Hz
IMD @ 1 kHz
IMD @ 6 kHz

Because I don’t have a lot of other amplifiers at my disposal, I simply used what I had available – the VE Runabout, and the Fiio E17K.
E11K (USD $60) vs VE Runabout (USD $100)
The VE runabout is VE’s first portable amplifier (from the same company that brought us the excellent Zen earbuds).  It is battery powered (9v battery), and at 235g and dimensions of 110x70x25mm, it is quite literally 3 times the size of the E11K.  It also measures below the distortion floor of my sound-card, and measures completely flat in frequency response.  It has a gain switch (only ~ +4-5 dB), and no bass boost. Battery life is incredible – it seems to go forever (I haven’t measured it yet – but will do so when I review it). According to VE it will put 150 mW into 32 ohms, which actually puts it behind the E11K on output power – but again it has driven my HD600 with absolutely no issues. In a volume matched blind-test, I can’t tell the E11K and Runabout apart – both sound excellent – clean and clear. But in a head-to-head comparison, the little Fiio beats it handily on size, portability, weight, form factor, features, and value.
E11K (USD $60) vs E17K (USD $130)
The E17K is a DAC/amp. It has an inbuilt battery (15 hour rating) and digital volume control instead of analog. At 110g and 104x62x13mm, it is marginally larger than the E11K – but the difference is mainly in length. It has 3 levels of gain 0dB, 6dB and 12dB, and has a tone toggle (-10 to +10 bass, and same on the treble).  Again it measures below the distortion floor of my sound-card, and measures flat in frequency. Its output is 200mw into 32 ohms (a little less than the E11K) and again has no issues driving my 300 ohm Sennheiser HD600s. Again in a volume matched blind-test, I would have difficulty picking the E11K from E17K.  The E17K does however have a very good DAC, tone controls, balance, and other inputs and outputs, and is incredible value at $130.
If I only needed an amplifier, and had no need of the other features the E17K provides, the choice of the E11K is an easy one to make.  However, if you like having the additional features, and have use for the dac function, then the E17K may represent better value.


I’ve now had the E11K for a year, and although I didn’t use the unit a lot in my early days with it, over the last 6 months, I have come to use it more and more. If you are using Fiio DAPs like the X1 or X3ii, I can thoroughly recommend the stacking kit too.
The E11K brings very good size, weight, power, and sonics together in an extremely budget friendly package. In fact, I cannot think of a better amp to recommend to someone just starting out in audio, and I think ultimately even seasoned audio lovers may really like what Fiio has brought to the table with this mini dynamo. In fact for a beginning audiophile, one of the best value for money combos you could get would be an X1 + E11K + stacker kit IMO.
Going back to my original list – I can say it has ticked every one of my boxes my boxes for portability, ease of use, output power, battery life, sonics, impedance, and gain.  If there were two minor things I would like to see changed it would be to see a two stage gain (maybe make the first at around -6dB, then at +3 dB and +12 dB.  This would give more usable play on the pot (fine tuning). And also I’d like to see the form factor return to a flat body– so that it is easier to stack (although with Fiio’s stacking kits this is less of a problem).
All in all, I would recommend the E11K to both audio starters and the more experienced without question.  For what it delivers, it is incredible value for money. 
You would rather recommend Q1ii only beacuse it has Dac, compared to E11K which is amp only? Or is Q1ii also improvement for it's SQ and amp capabilities?
Just realised you are talking about the Sine (headphones) rather than iSine (earphones). If that is the case and you need more output power - then yes A3 better choice. I still use mine a lot. Depends on what your price range is - because you have a lot of choice. Also depends on what else you might be powering. If you value true portability and don't mind spending a little more, then something like an Arrow would be a good choice too.
I'm not all about the output power,although would be nice to have spare power.I would just like to get as much as I can from my headphones,using dac/amp or amp only in price range up to 120$.What bugs me is,I don't know how good is iphoneX dac implemented in headphone lightning adapter,and should I stick with it and buy only amp,or look further for dac/amp combo.To summarize,I'm thinking between A3(if iphone's dac is good enough),Q1ii,A5 and E10K.Which one of these would you recommend?


100+ Head-Fier
Pros: Improved bass, improved lows, mids and highs, improved overall treble energy, neutral
Cons: Channel imbalance until level 2 in volume dial, slight static when music is paused, phone interference
First off, let me say now that I am not an audiophile. I am a fan of audiophiles though and I learn a lot from you guys. I'm more of a budget-audio-enthusiast and I'd like to keep it that way. Some parts of this review will be to re-affirm some of the observations with this product and probably add some recommendations for the benefit of our budget-conscious members like myself. So let's begin, shall we?

Update --> I purchased the latest version (2017) since I sold the first one some time ago. I am now pairing it with my smartphone (Lenovo K4 Note). See where it says (Update) below for some updates on the latest release version.


The latest packaging of the A3 (2017) has the following items:
  • 2 Hi-Res stickers, on the packaging and the unit itself.
  • 1 Ultra-short interconnect, as with the Fiio A5 (replacing the usual 3-inch ic)
  • 2 Rubber pads (replacing the rubber feet)
  • I'm stacking this with my phone so it's temporarily attached to my clear phone case with a reusable adhesive (sturdy but easy to remove Elmer's Tak 'N Stik). This does not damage the unit's surface at all.
IMG_20171214_135700.jpg IMG_20171214_135959.jpg


I always wondered if my headphones, the JVC HA-RX700, would benefit from a portable amp so I decided to dig some reviews and possibly find a good match. The most popular budget choice is the Fiio E6 so that was my first choice. Fortunately, there is a local store that lets me audition those first so I got to listen before deciding. First, it turned out that my headphones did benefit from the amp. There is some change in the sound quality, most notably in terms of clarity and bass but not necessarily in the sound stage. Not that I'm not content with how my headphones sound. They already sound great but I'm looking for that extra energy, especially in the treble and bass department. The E6 did that to some extent but EQ1 (red) is a little bit overbearing and the bass response is not that clean and muddied the mid-range a little bit. EQ2 (blue) sounded much cleaner but this time it lacked the bass energy I was looking for. I did not really pay too much attention to EQ3 (purple) and EQoff so I can't comment much on those. To cut the story short, the E6 is great for its price but I'm looking for more. So I stepped up the game, auditioned the E11K and the rest, as they say, is history. That history is actually written below.
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The build is superb. It has this feeling of indestructibility to it. The brand new unit's switches are tight and sturdy. The volume meter is smooth but not loose. I'm sure that it will last for years unless you intentionally or accidentally damage it. It feels like it can really take a considerable beating.

Design wise, it looks gorgeous. The brushed aluminum makes it look like a premiere gear. I know that some may prefer the line-in and out ports to be at the front of the unit, together with the volume meter but this design works for me. I have it strapped to my smartphone (Samsung Galaxy Mega 5.8 l9152), which has the headphone-out port at the top-end so I had the bottom-end of the amp facing that area then I plug in the interconnect and headphones from there quite easily. I just reach underneath my phone for the volume meter to adjust it ever so slightly then it's good to go. The power indicator being at the bottom-end also helps with my set-up. Again, it depends on where your headphone-out is. I'm pretty sure you'll find your way through it.


It added just the right bass energy I was looking for. It's not overwhelming but it's not lacking at all. It's really powerful and clean and it did not bleed out at all to any of the other frequency ranges.

It added a significant amount of treble energy. The highs (e.g. cymbal crashes and hits) are clearer and more prominent. Mid-range is also noticeably clearer.

Sound stage is about the same but more centered and balanced. It gives this concert hall effect, especially with songs that involved some orchestrated arrangements (e.g. Queen's Who Wants To Live Forever). Stereo imaging is unaffected though this is somewhat expected.

Overall, the sound is fuller and richer with a lot more energy. More importantly, I would say it's mostly neutral. My headphones' sound signature is maintained, with just the added prominence where I need them to be (bass and treble). So to my JVC HA-RX700 friends who are still wondering if those headphones sound "good" with an amp, they don't. They sound "great"! And they go perfect with the E11K.

CONS (Update)

1. Channel imbalance until level 2 in the volume dial - I did not really find this disturbing and this has been explained by Fiio quite clearly - (Update) It's still there, but less noticeable on the latest version (2017).

2. Slight static when music is paused - At first, I was disturbed by this but this turned out to be normal for low impedance and highly sensitive headphones. I tested this behavior against the store's test unit and the result is the same. What helps though is:

a) If you're using a portable source which is not very powerful (like a smartphone), set the source volume to max then control the volume from the amp. This worked for me and static is no longer there after pausing as long as I stay within acceptable (not too loud) listening levels but results may vary as you switch to a more powerful source. I believe the logic is that the signal from the source must be as strong as possible to avoid static/distortion. Again, please test what works best with your set up.
b) Switch to Low Gain. Your low impedance or highly sensitive headphones will likely handle the low gain volume setting more easily. In analogy, it's biting the right amount of food and it can chew it just easily. This is the safest bet. A quick notice though: High gain for me sounded more forward and open and bass is just a little more prominent. I listened to it enough to spot the difference. Low gain sounds "tighter" (not in a bad way) and a bit (a very tiny bit) more detailed but I like the high gain sound better. Again, it's a matter of preference. Just adjust that volume ever so slightly to avoid hearing damage.

(Update) When music is paused, it's silent (version 2017). This is a significant improvement from the earlier releases. There is still EMI when stacked with a phone but pausing music, I can not detect any noise, even with more sensitive IEMs like the KZ ZS3.

3. Phone interference - And yes, it's not perfectly shielded and you will hear the "tut tut tut" if a call or a text message is coming in or if the phone is picking up a strong signal but I think this is normal. It doesn't happen often and I believe it won't be a problem if you're not using a phone as a source so don't sweat it. Overall, it's still decently shielded in my opinion.


It takes about 4 hours to full charge. Keep a close watch if you're nearing the 4-hour mark. Upon full charge, unplug the unit as it heats up a little if not done so. I believe the unit has a built-in protection for overcharging but just to be on the safe side, unplug it at once when fully charged.

The published usability at full charge is more than 16 hours and I can attest to that. I believe rechargeable batteries improve after several charging cycles so I'm counting on it. If not, I'm pretty much content with about 16 hours of usage until next charge.


Fiio's published product page says, "great layering and medium and high frequency extension" and "with great control of low frequencies and smooth drive". I couldn't agree more. I'd highly recommend this product for its purpose.

For the budget enthusiast, if you can push your budget a little bit higher, go for the E11K instead of the E6. If you can audition both, you'll hear the difference, I promise. Don't get me wrong, E6 is decent but E11K is more than decent. It's on a league of its own. I even read reviews that it can compete with its higher priced big brothers but I'm not qualified to comment on that. I did not have the chance to try those. Just know that with the Kilimanjaro 2, your getting best value and sound at a reasonable price.

(Update) I believe overall that version 2017 is a better value in terms of accessories set and the improved noise floor. I can't imagine it to improve anymore but it actually did. Great job, Fiio! This remains to be your best value amp a few years after its release.


New Head-Fier
Pros: Audio Quality, Amazing Build,Looks,Battery
Cons: Pops up while starting, A tiny tiny bit of reduction in soundstage while enabling Bass (Varies from player to player)
First of all I'm not a basshead & I have 2 earphones & 1 headphone. This review is based on those
Things I used :
Tablet & Computer for source (Both having average/below average DAC I presume)
Headphones : Sennheiser HD 449,Sennheiser CX 180 Street II & Sony MDR XB70-AP
Review :
Build : One word,pretty amazing. It has lightweight brushed metal covered body without feeling
cheap,& it's sleek & sturdy. Every knob is carefully built & easy to access,especially the volume knob is
very well done. Rating : 5/5
Accessories :
A 3.5mm male to male almost 3 inch cable,
button-like rubber feet,USB charging cable,
Silicone bands (x2),
Owner's Manual,
Warranty Card. Rating : 5/5
Performance :
Battery : It has 1400 mAH Li-Ion battery and it lasts really really long. I've watched a Full movie with
3-4 hours of music playing & it's still showing that the battery is full. So good work there Fiio. Rating :
Sound :
Treble : Good emphasis on treble without making it too sparkly or fatiguing. Well detailed & well
spaced nothing to complain. Rating : 4.5/5
Midrange : Well detailed,almost true to the source. Good separation between midrange & other
treble-based instruments. Rating : 4.5/5
Bass : Well here comes the tricky part. What I've found,after few hours of listening from my
tablet that Turning the Bass switch on in my E11K (which has a discrete hardware accelerated bass
circuit) has a different effect on the music than Software accelerated ( Graphic EQs,Bass Boost
through Software) boosting,which comes with media players. Where the software accelerated Bass
boost/EQ is somewhat uncontrolled,noisy & sometimes bloats out the overall frequency range (if not
used properly),the discrete bass circuit of Fiio E11k doesn't do that... It adds a fine touch of depth in
the music without influencing any other frequencies. In that sense I would like to rate it the highest. But
there's a slight problem. I've noticed while playing from Tablet, turning the Bass ON reduces the
soundstage somewhat (a very little bit) & THAT also varies upon which player I'm running the musics
on. e.g the Stock music player performed best than High end players like Jet Audio/Neutron Player
etc. Before buying the amp I always thought my Tablet gave better sound in headphones than my PC.
But after attaching E11K with my Sennheiser HD 449 to my PC. WHOA. A whole new story. It
simply outperforms my tablet in every aspect. I used DFX to enhance SQ while playing games & was
satisfied with it. But after I attached E11k I found that which details were somewhat "PRESENT"
before are much "EVIDENT" now.  To be precise,E11k blows DFX out in every aspect.
It gives proper juice to your headphone & sounds amazing where DFX  now feels inferior.
I don't have to listen to it to find out the detail... It's already there.
And the constriction of soundstage I referred before in my tablet is almost negligible (or almost
absent) in the PC. So to sum it up,It's the DAC that has lion's share in the SQ. Even though Amps
chisel it out,it cannot change what's coming to it as a feed. So in Bass I'll rate it 4.5/5
Performance Variation : Although E11k increased the SQ of all 3 headphones/Earphones of mine. I
got most out of it while using with my Overhead HD449. I think the CX180s & XB70s were well fed
from my tablet only... Using E11k makes it slightly better though,but it doesn't make a difference as it
makes with HD449s

Soundstage : Satisfied with it. Almost True to the source. Good instrument separation.
Price : Around Rs. 3.7k +. I haven't used any amp before so can't comment on this section :p
Overall : A highly recommended product,if you think you need more juice for your headphone. More
suitable for Overheads. It's highly recommended to use it with a good DAC. I'm hoping to buy one in the future.Thank you for reading. I'll give it  4.5 stars out of 5


Reviewer: PMR Audio


Fiio is a Chinese maker of audio equipment that has become well known for offering good gear at highly competitive prices.   With a lineup of competent, if not highly compelling, DAPs, amplifiers, and DACs, Fiio has generally been incredibly fast in reacting to audiophile market trends.  The previous E11 was a budget portable amplifier aimed primarily at winning the hearts (and ears) of IEM/ portable headphone users.  It turned out to be quite successful, and received some serious praise from many members of the audio community for offering a solid SQ in a small package (size and budget-wise).  However, the E11 did leave a few things to be desired, including a better housing, sharper design, and a refined SQ.   
Before I go any further, I would like to offer a big thank you to Sunny at Fiio for sending a review unit for the purposes of writing this review.  As always, I am neither an affiliate nor an employee of Fiio, and all photos are taken/ owned by me.

Weight: 92 grams
Audio Input: 3.5 mm Jack
Drive Ability: 16-150 Ohms
Output Power: 270 mW (32 Ω/THD+N<1%)
                        450 mW (16 Ω/THD+N<1%)                                                  
THD: 0.004% (1 kHz)
Frequency Response: 20-20 kHz
Input Sensitivity: 2.4 V (GAIN=L)
                           0.8 V (GAIN=H)                                                                              
Gain: -3.8 dB (GAIN=L)
         11.7 dB (GAIN=H)

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The E11K comes in a no frills package.  The thin laminated paper cardboard box opens to reveal a pullout tray covered with faux crocodile skin.  It is a rather odd design choice, but Fiio products aren’t about awe-inspiring unboxing experiences anyways.  The expected accessories can be found, including a few rubber bands, a 3.5mm to 3.5mm cable, and 6 3M-rubber feet.  It is a bit of a shame to see the 30-pin to 3.5 mm cable go, but I guess that that can largely be attributed to Apple’s move to adopt the all-digital Lightning cable.​

Fiio has definitely stepped up its game in terms of build quality.  The new E11K now sports the same black, brushed aluminum exterior that can be found on the Fiio X3 DAP, E12 Mont Blanc, etc. Needless to say, it looks pretty darned good. The volume control feels solid, and is protected by a conical leading edge on both sides (Astell & Kern anybody?).  On the same side as the volume control are the gain and bass boost controls.   Both controls are flip switches made out of plastic, and do jut out a fair bit from the player.  Take extra care as you remove the rubber bands from your E11K/DAP setup, as simply sliding it off the player will cause the rubber band to slide onto the two plastic controls (and possibly snap the plastic bits).
On the other side of the amp are the Micro USB charging, line out, and headphone out ports.  Why Fiio chose to have the headphone out on the opposite side of the volume control is beyond me.   The ergonomics of this setup are naturally rather awkward and even a little troublesome at times.   I had to reach deep into my pocket (thankfully, not for my wallet) to get to the volume control.

The Fiio E11K has juice.  For a 60 dollar amp, it can power IEMs wonderfully and some headphones quite well.  Turning the E11K on and off, I couldn’t help but to notice the rather significant pop.  To mitigate possible damage, I generally preferred to unplug my earphones first in both of the above situations.  This is troublesome, especially considering that this amp is most often used in portable setups.  I should really just be able to just flick toggle on and off with relative ease and not have to worry about possible hardware damage.
The sound is relatively pleasant, and leans slightly towards the warmer side of things.  The amp is relatively conventional, and doesn’t make any unexpected changes or additions to SQ (not that an amp should really be doing the former in my opinion).  Soundstage is moderately sized, but I wished that it was slightly larger.   Imaging, like the soundstage, is pretty good as well.  However, do not expect to be able to pinpoint every detail or the location of the various instruments.  It is very important to note that this amplifier is only sixty dollars though!  For sixty bucks, it’s doing a great job at simply fulfilling its job scope –amplifying sound.
Bass boost is surprisingly unobtrusive, and adds bottom end fullness without causing significant bleed into the mids.  In fact, some might be disappointed that this isn’t producing a huge bass bump.  I found this to be a great thing for IEMs though.  More often than not, IEMs need just a slight alteration of SQ and not massive overhaul courtesy of the amplifier.  For my ATH-IM02s, the Fiio E11K gave just a small push that helped to make the earphones more musical (by enhancing low frequency performance).

Fiio has done a great job in my opinion.  While users who have listened to more expensive setups will probably not be wowed by the E11K, it’s hard not to be impressed by the good SQ at the extremely reasonable price point.  For portable use, I feel the E11Ks do a wonderful job, and those who have not been amping their earphones/headphones or are considering a more portable setup should definitely look into this mean, lean, amping machine.
Spammers on headfi...this is unique....
Input on the bottom works if you're feeding it from an iPhone. Volume control can stay at the top with the whole kit on your pocket.
I love this amp, and doubly so at the price point. I would like to add to the review that I hear no interference or background noise with this amp. It is remarkably quiet. 


twister6 Reviews
Headphoneus Supremus
Pros: sound quality, build, output power, bass boost
Cons: Headphone/Line In ports are on the opposite side of volume control
This is a Review of FiiO E11k portable headphone amplifier., available from FiiO's US distributor MICCA Store: for $59.99.

If you think the only purpose of headphone amplifier is to make a sound louder, you will be in for a big surprise to discover how much it can shape the sound and contribute to improvements in details, soundstage, etc. It is true that some headphones require more power to drive them, but I would like to focus in my review on the contributing factor of the sound improvement while using amplifier connected to a portable audio source. With E11k being my first portable headphone amplifier, I don't have too many references for comparison, though prior to E11k I have used E18 as an amplifier. Here is my impression of this latest product from FiiO.

Actually, I should start first by mentioning this is an updated version of FiiO popular budget amplifier, E11. One impressive thing about FiiO, beside constantly working on new products, they also revisit their older models to improve the design and to update the components. That's exactly what happened with E11 model where the design was updated from inside out.

Arrived in a small box (as it turned out, my review unit had an older packaging where 2nd batch will be similar to E10k), beside E11k there was also a charging usb cable, a basic 3.5mm audio cable, a pair of silicone bands, 6 pieces of rubber feet, instruction manual, and warranty card. The unit itself is very compact, measuring about 91mm x 56mm x 13.5mm, with a solid aluminum alloy body that feels very smooth in your hand and also relatively lightweight at only 92g. The shape reminds me of a drinking flask due to it's rounded toward the edges surface and volume potentiometer knob between two ramp up pieces at the top. Next to the volume, you have toggle switches for Low/High Gain and Bass boost on/off. The power turns on by turning the dial of the knob past zero where on the opposite side you will find a blue led indicator next to micro-usb charging port. On the same side as micro-usb port, you also have headphone output and aux input (3.5mm ports) located symmetrically on each side of micro-usb port.

I do have to mention it was a bit awkward to see Headphone and Line In ports on the opposite side of the volume knob, and perhaps for some this will affect a connection of audio cables and the logistics of placement to have access to volume control. At the same time, it really doesn't require to use two fingers to turn the volume knob, and I was able to use just my thumb. As a matter of fact, I tried my X5 with HS6 kit (designed for a larger E12 amp) using a single rubber band to hold down E11k, and found it to be working quite well. Also, want to mention that I really like the audio cable from HS6 kit, something you can get separately as L16 short cable from FiiO. Furthermore, I know some will notice a shape of E11k to be not perfectly flat, but next to a flat surface of a DAP (even using X5 without a silicone skin for the purpose of HS6 kit) - it felt sturdy without wobbling. For an extra security, you can use included rubber feet that just stick on to the body of E11k. Personally, I think E11k will make a PERFECT pair up companion for the upcoming X1 DAP.

Don't let the small size of this amplifier fool you since it actually hosts a hefty 1400 mAh battery (non replaceable) which can provide over 16 hours of continuous play. I have been using E11k in a low gain setting for almost two weeks now and have a feeling it can probably stretch pass that limit. And even if you run out of juice, you can continue using amplifier while charging it up. Gain toggle provides a decent boost in volume to assist in driving demanding headphones, and the extra power actually helped to bring up more details even in less power hungry IEMs. I also found Bass boost to be surgically clean, where flipping that toggle provided a more controlled enhancement of sub-bass quantity and some mid-bass punch without spilling into mids and muddying the rest of the spectrum. In contrast, E18 bass boost wasn't as tight, and bleeded a bit into lower mids.

So how good does this amp sounds and how much improvement are you going to get over your built-in amp? There is no simple short answer to this question, and that is a beauty of amplifiers where it will depend on it's pair up with your source. One thing I found for sure: the sound will always improve, but to what degree you can never predict so it was a journey to try different hardware sources as well as using connection to Line Out (LO) or Headphone Out (HO) to find a better combination. Typically, you want to drive your external amp from LO, but it never hurts to experiment. At the current moment my two main DAP sources are X5 and AP100, and for example I found E11k connected to HO pairs up better with AP100 rather than X5. But once I switched to using LO port, I found a combo of X5 + E11k to show more improvement over AP100 + E11k. As a matter of fact, while I prefer AP100 built in amplifier over X5 built in amplifier (by comparison of direct HO connection and while AP100 is in 24b/192k oversampling mode), X5 actually sounds much better with E11k from LO. Also, comparing the sound between X5 with direct headphone connection vs LO with E11k, I found the sound to get wider and deeper (soundstage), overall tighter, brighter with more details while still being smooth, and a significant bass improvement (deeper and punchier). A performance of X5 paired up with E18 as amplifier connected to LO was inferior in sound quality to E11k where E18 colored the sound to be darker, less transparent, and with less details in comparison to E11k.

Overall, I found that amplifier adds another variable to a complicated equation of sound where you already have an array of file formats, different hardware sound sources, and various headphones. There could be numerous combinations and it's a never ending journey. One thing I discovered for sure, if you are serious about sound quality - amplifier is a must have addition to any setup. With E11k being a very portable and a very capable amp, I found it to provide a noticeable improvement to X5 DAP when comparing direct HO connection vs LO w/E11k. It has just a perfect balance of clarity and transparency with a touch of warmth without adding too much color or distortion when paired up with a capable DAP that has Line Out. For use with smartphones or supported tablets, I would still recommend E18 which goes straight from digital domain to internal DAC/amp of E18. For everything else, E11k is an excellent portable amplifier on a budget!

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Thank you for your review. It helped me to pull the trigger and actually I scored an audible improvement with my iPhone5, FLAC and Senns Momentum IEM/AKG Y50.
The latest cans are a little picky with power and connected to HO of iPhone even a nearly full steam didn't deliver. It turned out to be a noticeably different and darn sight better experience with this amplifier, which with High Gain a Bass Boost Off, gave me a nearly flat sounding image, with more 3D experience. Gone was the (slightly) V-shaped frequency response.
I'm still making tests with the Senns IEM, but one thing it is quite clear: Bass Boost off most of times :wink:
Gah, i'm desperately trying to resist the urge to buy the e11k, then i've stumbled upon your review. Guess i'll just have to order one, then.
Good job sir!
I've been using this little amp with my Samsung Galaxy Tab S, Nokia 928 phone, and my favorite brick - my original 32 gig Zune. The amp sounds great - it presents a nice black background with my setups (either using Audio Technica ANC23 or Hifiman RE600) and overall just does a nice, serviceable job of what an amp is supposed to do. 
Now looking hard at a Fiio X3 to go with it.....