An excellent portable headphone amp!

A Review On: FiiO Kilimanjaro 2 (E11K) Portable Headphone Amplifier

FiiO Kilimanjaro 2 (E11K) Portable Headphone Amplifier

Rated # 16 in Portable Amps
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Review Details:
Audio Quality
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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!

Here are the pictures.























Nice review twister! I wonder how it will do with the new X1.
WHY DID I READ YOUR REVIEW???!!!! I originally decided to not buy one because my phone is sufficient but your review makes me want to reconsider.

Absolutely great review!
Is there any hiss/noise/hum (and under what condition did you find it), or is the background black? Sorry, just wondering because the price is so cheap.
@howdy : I guess will find out sooner or later, probably sooner ;)
@souhikyaku9 : noise/hum attenuates to minimum.  For example, AP100 HO has a high gain output (by default), and paired up with ATH-IM50 - you hear a lot of background white noise/humming when idle (no music playing).  Connecting E11k to HO of AP100 and then IM50 to E11k - silences the noise.  Output is very clean.  Similarly driving IM50 from my Note 2 (in idle, a lot of hissing), but with E11k connected to HO of my phone - noise is attenuated, though more attenuation in low gain vs high gain which understandable.
Nice! I'll probably pick this up for a small amp. Any comparison to original E11 or E12 would be appreciated by many.

AND thanks for pointing out sound signature alterations. It drives me batty when I see people posting about how you don't need an amp for such and such DAP because it had PLENTY OF POWER to drive such and such headphones. IT'S NOT ALL ABOUT POWER. Sound signature matters, too. Different buffer, capacitor, opamp combinations provide that. Kudos for pointing that out!
Oh yeah, how does it do with sensitive IEM? What are we looking at on the volume knob - 2, 3, 4...?
I was hoping they would drop the specs to 10hz and raise the top end over 20k hz. 
I think I have to have one, if for no reason other than I am sick of carrying around a "Mini USB" cable only for charging my current E11 (when everything else uses Micro USB).  Looking forward to reading sound comparisons with E11 / E12.  Nice review!
Ok, twister6 thanks a million for your review and comments.  I wanted to try a Fiio amp just to see what the company is all about, and this seems like the one worth getting.
@nmatheis : don't have any high sensitivity headphones anymore (used to have Doppios).  You can always use a little impedance in-line adapter to fix that ;) Something like this one from Dunu:
@yacobx : amp specs are not the same as headphones which indicate how low/high they can go.  So, don't worry about 20-20kHz, frequency response of your headphones will be the only limiting factor in response.
I think the fact that they separated the volume pot from the in/outs are a plus. One of the thing I dislike on my current E-11. The design is much nicer too, more inline with the E12 which I also own. Thanks for the review.
I've been eyeing this bad boy for a while just because of it being a perfect fit with any Android device. I never pulled the trigger since I hadn't read any well written, well informed, and positive reviews. Until now that is.
Thank you for the awesome review. This product has now been bumped way up my "to buy" list.
really enjoying my E11K, it drives ATH IM50s with authority and the bass boost is perfect for streaming psytrance sets from festivals on SoundCloud from!
Just ordered this in part due to your review. Where can I get the short braided cable that connects it to your phone that is in the pictures? 
@caschw : it's FiiO L16 cable, $12.99 with free shipping from Micca store: - silver plated OFC cable, high quality stuff!!!
@twister6 Thanks!
Thank you for your well written review. You recommended the E18 for smartphones, may I know if it's compatible with iPhone 4S with IOS 7 and the new iPhone 6 with IOS 8? 
Then what is your recommendation for me? Thanks
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 ;)