FiiO Kilimanjaro 2 (E11K) Portable Headphone Amplifier

Average User Rating:
4.6/5,



Recent User Reviews

  1. Brooko
    4.5/5,
    "Fiio E11K (A3) Kilimanjaro 2 – Simply amazing value in a portable amp"
    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

    INTRODUCTION

    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.
     
    ABOUT FIIO
     
    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.
     
    DISCLAIMER
     
    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).
     
    PREAMBLE - 'ABOUT ME'.
    (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.
     
    FURTHER NOTES
     
    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.
     
    WHAT I LOOK FOR (NOW) IN A PORTABLE AMP
     
    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
     
    PORTABLE AMPS I’VE OWNED IN THE PAST
     
    1. Fiio E7, E11, GoVibe Porta Tube, Headstage Arrow 12HE 4G, Beyerdynamic A200p
    2. Current portable amps E11K, E17K, VE Runabout
     

    THE REVIEW

    PACKAGING AND ACCESSORIES
     
    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
    Accessories
    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


     
    TECHNICAL SPECIFICATIONS
     
    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
    SNR
    >108 dB
    THD
    0.004% (1 kHz)
    Frequency Response
    20 Hz-20 kHz
    Gain
    -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
    Dimensions
    91 x 56 x 13mm
    Outer Material
    Brushed Aluminium
    Headphone Out
    3.5 mm
    Weight
    92g
    Battery Capacity / Life
    1400 mAh / ~ 16 hours
    Recharge Time
    4 hours

     
    BUILD / DESIGN
     
    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.
     
    Underside
    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

     

    HEAT AND POWER
     
    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.
     
    FEATURES / USEABILITY
     
    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.
     
    BATTERY LIFE
     
    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.
     
    SONICS AND PERFORMANCE
     
    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


     
    COMPARISONS
     
    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.
     

    E11K VALUE & CONCLUSION

    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. 
     ​
  2. audiophilefan
    5.0/5,
    "Fiio E11K - the best value headphone amp price-to-performance wise"
    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?
     
     
    REASON FOR BUYING
     
    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. [​IMG]
     
     
    BUILD AND DESIGN
     
    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. [​IMG]
     
     
    SOUND
     
    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. [​IMG]
     
     
    CONS 
     
    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 - http://fiio.me/forum.php?mod=viewthread&tid=40050.
     
    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. [​IMG]
     
    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. 
     
     
    BATTERY LIFE
     
    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.
     
     
    FINAL THOUGHTS
     
    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.
  3. harryrupam
    4.5/5,
    "Small Sturdy & Powerful portable Amp"
    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
    accessories.
     
    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 :
    5/5
     
    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

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