Fiio E17K ALPEN 2 USB DAC Headphone Amplifier

General Information

The FiiO E17K is a portable headphone amplifier and digital to analog converter (DAC). The E17K has a built in rechargeable lithium battery and USB charger, allowing you to charge on your PC or with a USB adapter. The E17K has fewer buttons on the front than that of its predecessor the E17. The FiiO E17K has a new multi-functional wheel that responds to both turns and clicks, providing an intuitive agile control replacing many buttons from the older model. The all-new E17K Utilises the SA 9027 USB receiver, allowing the E17K to be used as an external sound card for your computer. This supports up to 96 kHz/32bit and supporting DSD decoding * (with ASIO driver and SACD plugin). The FiiO E17K exploits TI's all-new PCM5102, which processes higher S/N ratio, lower distortion and more linear digital-analog conversion characteristics. Also added to the new E17K is the TI's flagship OPA1612, as a low pass filter and OPA1642+LMH6643 in an OP+BUF architecture usually only seen in high end units.

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New Head-Fier
Pros: Soundstage, good build, mids, sound feels... big?
Cons: Noise floor, sound itself is just unpleasurable.
Treble is mediocre, bass is awful (boomy and textureless).
Mids are good.
You can overcharge it and kill the battery, I mean, how could they actually NOT put a charging controller in there, it's not a 10$ product.
Packaging is kinda good, though no OTA cable, which is a bit hilarious.
In comparison, Cayin N3 obliterates this item in DAC mode.


Reviewer for The Headphone List
ryanjsoo's Reviews
Pros: Feature rich UI, OLED screen, Clean sound with a hint of warmth, Refined treble, Quite resolving
Cons: Price/performance isn`t as great as the Q1, Chamfer gets scratched, Could come with an OTG cable, Scroll wheel could be more sensitive

Introduction –

The e17k is technically a higher model than the Q1 but it is also older. It actually uses the same DAC chip as the Q1 (PCM 5102) but the 17k has a cleaner, more complex amp section. The USB receiver is also improved, allowing for higher bit depth file support. It is interesting to see the sound changes based purely upon the amp and the e17k provides performance that is superior to using the Q1 line-out through my JDS Labs Cmoy BB. It also provides some interesting features rarely seen outside Fiio`s range of AMP/DACs, improving upon the success of its predecessor the renowned e17.


Accessories –

The e17k is one of Fiio`s newer products, adopting a compact square box with easy on the eye record style front graphics.


There are some brief specs on the back of the box, enough to compare the e17k to other Fiio models for instance. It is a pretty minimalist experience on the outside and the matching simplicity of Fiio`s line-up looks pretty neat in store.


What isn`t minimalist however is the accessories that Fiio includes with the e17k, it`s a real step up from the Q1 in this regard. Sliding out the protective internal tray reveals:

  1. The e17k itself
  2. A micro b cable
  3. A 10cm 3.5mm interconnect
  4. A coaxial to 3.5mm cable
  5. Three screen protectors
  6. Two mounting bands
  7. A neoprene pouch
  8. Authenticity and instructional paper


It comes with about everything you could hope for and more, I really appreciate having the screen protectors for example. I would have liked an OTG cable, but adapters are cheap and the e17k doesn`t technically support OTG much like the Q1. Despite that, it still worked perfectly with all of the devices I tested it with; HTC M8, LG G4 and Galaxy S6 Edge.


Design –


Now onto the device itself, the e17k seems well thought out. The build is much more complex than the Q1 but it remains about the same size in all dimensions despite the added features. Fiio avoids cluttering the look by placing most of the functions, such as toggling charging over USB, within the software itself. This adds a few extra steps over the hardware switches of the Q1, but the menus are simple and frequently used features are easily accessible from the front buttons. The flat body of the e17k is much easier to stack than the flask-like Q1 and it is similarly well finished if not better.


The front and rear faces have the typical Fiio dark brushed aluminium that feels very solid and scratch resistant, flexing only under excessive force. There is not a hint of plastic on the externals device apart from the scroll wheel enclosure, and it looks quite a bit more premium than the Q1, though the Q1 is still very sturdy in the hand. The jacks are all gold plated and don`t crackle when rotating the plug.


There is a small chamfer that runs the perimeters of the front and back that is finished in gloss black, adding a bit of impact to the aesthetics, reminiscent of HTC`s styling. I bought my e17k used and the device had no wear on the faces which is a good sign, but the chamfers had some scuffing, revealing the underlying aluminium. If you`re more perfectionist, the chamfers are the main area of wear on this device, the faces are surprisingly hard wearing despite the intricate brushed finish.


Of note, all of the writings are laser etched into the aluminium so they will resist fade.

On the front is a small OLED screen. It`s black and white and also relatively low res but works very well for what it`s intended. I much prefer this B&W colour scheme over the vivid stained screens on most Chinese DAPs, DACs such as the older e17. It looks more mature and refined.


Of note, OLED screens are inherently very visible under strong light and I didn`t run into any problems using the e17k outdoors. The UI is polished and I experienced no bugs over a two week period. I noticed that there is a Fiio boot-up screen and a “bye bye” shut down screen which is a nice added touch from Fiio. You can adjust volume using the side mounted scroll wheel but it also clicks to open the settings menu and select the highlighted option.


Within the menu you`ll find eQ settings, gain and toggles for screen timeout, usb charging, sleep and channel balance. The eQ`s are similar to that on the X3, you have 10 settings, 5 either way, for both bass and treble whilst mids stay flat in between. The bass boost works well and the adjustments intervals are spot on. The +-10 on each side is a bit elusive as it scrolls in intervals of 2. It would be good if you could save eQ profiles but the UI is probably too simple to allow for that. You can also use the front buttons to change the source between USB, AUX and COX. The screen displays the sample rate and bit depth at the top. Either it`s not accurate or my sources aren`t outputting properly, because it`s locked at 96khz 24bit on my laptop and 44.1khz 16bit on my phone regardless of the file, so I`m not too sure about this feature.


I do wish that the scroll wheel was more sensitive, but it works well otherwise. The digital volume control has no channel imbalance, and I didn`t find myself accidentally pressing it, the feedback is nice and clicky. It looks in-line with the rest of the device, matching the buttons on the front, but I suspect it is actually made of plastic or at least a very light metal. The input/lock and power/back buttons are both well made with similarly receptive feedback and a nice concentric texture. They are easy feel for in your pocket, the power button is smaller so differentiating between the two is simple.

The power button has a clear rim with an underlying LED that displays status: blue when powered on, red when battery is low or the device is charging and purple when charging whilst in use. It is simple and looks neat, the small LED is not nearly as intrusive during night use as the front mount light on the Q1. 

There is also no pop when plugging/unplugging headphones but there is a bit of crackle and also some crackle when turning the device on and off. Interestingly, the Q1 is actually silent at all times even when plugging/unplugging and turning the device on/off, though it might just have a weaker amp section. The noise is hardly distracting and much quieter than that experienced when using a smartphone for example. Other than that the e17k is as silent as the Q1 in low gain, which has close to a silent noise floor.


Overall, the e17k looks advanced but not gaudy, sleek but not plain, it`s what we have come to expect from Fiio, a well built and attractive device with a balance between form and function.


Sound –

The e17k is a very good sounding DAC/AMP that sizes up well when compared to competition in its price range. It doesn`t strike the amazing value/performance ratio of the Q1, and the extra price is mainly for extra features rather than sound quality, but there are definite upgrades here and there that create a considerably stronger audio performance. Even for the $180 AUD RRP, the e17k can still be considered good value.

I`ll start with a comparison to the Q1, a device that I owned for a good 6 months before upgrading to the e17k. First off, there is plenty of volume, but you might struggle with very high impedance headphones such as home orientated planars. The e17k will get louder than the Q1 on its highest gain setting, it will also get quieter on its lowest without channel imbalance.

The e17k drives my Oppo PM3`s better with a stronger amp section. It is also slightly less noisy than the Q1, which is already very quiet. I found that the noise floor on the e17k does not increase too much with higher gains; whilst the Q1 goes from near silent to noticeable, the e17k goes from silent to near silent. This will be a nice improvement for those using higher gains with less sensitive earphones in particular, but headphones shouldn`t pick up hiss on either.

Bass is slightly fuller than the Q1 but also a bit more resolving, the mids are slightly more detailed and transparent but also slightly dryer. It retains the minimal warmth of the Q1 but still sounds very neutral.

The greatest improvement over the Q1 is in the highs where the e17k produces a smoother and more refined sound. In acoustic songs for example, listening back to back made the Q1 sound a little more rolled off and also a little coarser but both are much improved over my inbuilt laptop sound card. The soundstage is clearly broader than the Q1, it`s a step or two more spacious and imaging/separation is also improved as a result. Timbre is slightly improved as well. Overall the e17k combines a few minor sound upgrades here and there with an immediately superior treble response and soundstage to create a coherent upgrade from the Q1.

I recently had the opportunity to test the Fiio e18 and sensational Chord Mojo, both for a few hours. For starters, the relation between the e18 and e17k is similar to that between the e17k and Q1 in that it is an older device but also a higher range one. Skipping the spec sheet, the real world performance of the e17k and e18 is surprisingly similar. I did notice a very slightly cleaner and detailed sound from the e18, perhaps ever so slightly more soundstage too.

The e18 was slightly noisier to my ears however which compromises low level listening in some circumstances. I also didn`t appreciate the more sterile presentation of the e18, it was a little thinner in the mids and a little brighter in the highs. So although the e18 is technically better, I prefer the tonality of the e17k. The e17k is smoother sounding and the high end was actually more refined and laid-back. This is mainly because my listening was done through the brighter sounding ie800`s and W30`s, both earphones that didn`t synergize with the e18`s rawer sound and higher noise floor, but the e18 may be worthwhile if you have a darker headphone, the re400`s and Oppo PM3`s for example sounded very clean through the e18. Despite that, the e17k also has extra features and is appreciably smaller, it will be easier to stack with small phones such as older iPhones.

The e17k doesn`t fare so well when compared to the Chord Mojo, but this is hardly surprising as the Mojo costs over five times as much. The mojo impresses with an amazingly clean sound that marries the smooth, organic sound of the e17k with the clarity and detail of the e18 and then adds some on top. The Mojo also has a particularly standout build, a full alloy enclosure with really surprising weight in the hand, it`s easily twice the weight of the e17k. The Mojo also has those mystical glowing buttons that really catch the eye and double as file bit depth/sample rate indicators. It`s a really neat device overall but you pay a premium for that proprietary tech. How much better is the Mojo? Not enough in my opinion, it was immediately superior to the e17k and e18, but not $800 superior. The Mojo is still a very impressive piece of equipment in itself and hopefully we`ll see this technology will filter down to the $200 price range in the future.


Verdict –


The e17k is a sizeable upgrade from the Q1 sound wise, but add on the extra functionality, the easy OLED UI and the higher quality finish, and the e17k becomes a much more attractive product. In fact I would easily recommend the e17k over even the e18 any day, simply for this added functionality.

The e17k provides a solid sound quality improvement over any modern smartphone, even my HTC M8, but also makes your listening more consistent. You can have the exact same sound and the exact same eQ profiles on every device you listen to regardless of that device`s inbuilt features, you can bypass those the terrible iPOd eQ`s for example. Sometimes it becomes difficult to justify the price of DAC/AMPs, how much they affect your listening experience depends heavily on your current source, but the e17k offers genuine upgrades to your audio experience.


Accessories – 10/10, Comes with everything you could ever need to compliment the device. Could come with an OTG cable, but they are easily come by. Extras such as the case and screen protector are appreciated.

Design – 9.5/10, The build is very nice, the buttons are well marked and the device is easy to navigate. Every part of the e17k is well finished and well thought out. The scroll wheel could be a little more sensitive, but that might be because I`m used to an analogue pot.

Sound Quality – 8/10, Well integrated DAC mated to a well-designed amp section is good for portable use and some home use. Provides plenty of volume in high gain and black noise floor in all gains is optimal. Big improvement over stock DAC and pure amp, more convenient too.

Value – 9/10, The e17k does not provide a big upgrade over the Q1, but costs almost twice as much. There is disparity between the sound quality leap and the price leap, but the e17k is far more feature rich and the design is much improved. Fiio also provides more accessories. The e17k feels that extra bit more refined and premium.

Verdict – 9.5/10, While the e17k has specs insinuating strong audio performance on paper, the main attraction is the OLED screen and simple, user friendly UI that enables some features uncommon in this price range, or on portable DACs at all. That is not to say that audio is not the focus as the e17k also produces a very versatile sound that is the next step up from the Q1, just don`t expect an immediately superior sound.


This review was taken from my blog, please have a look for more reviews like this and some guides, thanks for looking:


Extra – 



I found the QCY pleather pouch to be a great fit for both the e17k and Q1, since they are quite similar in size.


The drawstring won`t close but it works fine as a pouch as opposed to a bag. The pleather is very supple with a  soft interior.


The ad mentions that it is “shock resistant”, and there is a small amount of sponge to the material, but it won`t protect from any meaningful drop.


They`re also very cheap, about $2 each and will help maintain that intricate brushed finish. Just search “QCY pouch” on either Aliexpress or Banggood and you will find a few sellers offering competitive pricing, just be prepared to wait up to a month for shipping.

What are your thoughts in comparison to the e17 as a dac/amp combo on the go?
Sorry, I haven`t heard the e17, if it`s similar to the X3, then the sound should be quite competitive, a little bassier and a little darker, but quite similar. The e17 is the same size as the e17k so on the go listening should be fine, the e17k is about 2/3 the size of the e18 and thus most android phones, it is a little heavy but using some reusable double sided tape or bands will do well to fix this. The scroll wheel of the e17k will work much better than the buttons on the e17 though, you might be better off looking at an amp like the A3. 
Roving poet
In my humble view E17k worth considering in 2021 because of the tone controls. Can't find an EQ app that works, with Apple Music, so Dac with any EQ worth having, also Qudelix 5k worth considering which has very good 10 band EQ but I haven't tried that one and it's mainly for Bluetooth anyway...
Pros: Transparency, build, value, battery life, features, bass/treble tuning, input choices, good gain options, docking with K5 desktop amp, portability
Cons: I am struggling to find any (at this price point) – difficult to set-up for DSD


For larger images (1200 x 800 - simply click the image)
For many newcomers, choosing an amp or amp/DAC is a minefield given the many options and price points available now. Coupled with that is the many opinions tendered on what adding a new amp or amp/DAC can bring to the table in terms of clarity! details! soundstage! As I’ve gained a lot more experience, and (more importantly) tested more, I’ve come to realise that many of the differences I thought I’d previously heard are pretty subtle, and mostly occur because I wasn’t volume matching while comparing different amps or sources.
And that brings me to the product I’m reviewing today – Fiio’s E17K (Alpen 2) portable DAC and amplifier.  I’ve now had the E17K for more than 6 months, and it has become my staple for testing (along with the X3ii DAP).  From going to a guy who rarely used an add-on amplifier any more, I now use the E17K at least once every day. For the value and feature proposition it brings to the table, I’ve found it to be one of the finest products Fiio has ever released.
So if you’re looking for a portable DAC/amp, and/or one that can be used both portably and integrated into a desktop set-up, please sit back and come on a little journey with me.  And let me introduce and tell you about the wonderful E17K.
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 E17K (Alpen 2) portable DAC and amplifier I’m reviewing today was sent as an evaluation (rather than review) sample to me by Fiio earlier in 2015. It was sent as an evaluation unit, and I was under no obligation to write this review – I am writing it because this particular product needs more recognition in my opinion. I am not affiliated to Fiio in any way, and this is my honest opinion of the E17K.
I have continued to use E17K and for follow up reviews, and I recently inquired if I could purchase the device from FiiO.  They have insisted I keep the E17K for my own use. So I acknowledge now that the E17K I have is supplied and gifted completely free of any charge or obligation.  I thank FiiO for their generosity. 
(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, Alclair Curve2 and Adel U6. 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 E17K both with my X3ii, stand alone with PC and netbook (to test the DAC), and also docked to the new Fiio K5. 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. For the purposes of this review, I have (from this point) simply referred to the Alpen 2 E17K as “E17K”
  2. Volume matching was done with a calibrated SPL meter and test tones (1 kHz) when required for comparison.
  3. Frequency response measurements were taken using a relatively cheap Startech USB soundcard, which while measuring decently on loopback (0.012% THD and 0.024% THD+N) tends to be the limiting factor measuring THD, THD+N and IMD – as I seem to be limited by the Startech’s performance.  So I am taking Fiio’s distortion published measurements as truth, and this time not measuring myself. When I did measure, they are below the threshold of audibility anyway.
I thought I’d list (before I start with the review) what I would look for in a portable DAC/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. Hardware EQ if possible
  9. Easy installation of DAC drivers and
  10. Value for money
  1. Previous = Fiio E7, Beyerdynamic A200p
  2. Current = Fiio E17K, Q1, Cozoy Aegis, iFi Micro iDSD


Retail package in profile
Front of retail box
Rear of retail box
The E17K arrived in Fiio’s retail packaging – a white, red and black box measuring 130 x 130 x 30mm. The front had a picture of the E11K, and the rear has some specs and other information in English and Chinese. Opening the outer retail box reveals an inner box with two compartments – one holding the E17K and carry pouch and the other has the accessories.  The accessories include:
  1. Soft cloth/neoprene carry case
  2. 1 x 3.5-3.5 mm interconnect cable (Fiio’s L8 mini to mini)
  3. 2 rubber stacking bands
  4. A USB to micro-USB recharging cable
  5. Coaxial connection adaptor
  6. Spare screen protectors
  7. Warranty and instructions
Inside the retail case
E17K and accessories
Cables and Fiio bands

The entire package is very practical, covering everything you initially need for the E17K.  A small note – and I’m not sure if this is a permanent change, or just my review unit – but instead of the usual inclusion of silicone feet, I received an 80 x 45mm thin silicone stacking pad. This is excellent for placing between source and E17K and eliminates any moving around or scratching/damage.
The table below lists most of the relevant specifications for the E17K.
Output Impedance H/O
<1.1 ohm
Max Output Power @ 32 ohm
200 mW
>113 dB (AUX IN)
0.003% (1 kHz)
Frequency Response
20 Hz-20 kHz
0 dB / 6 dB / 12 dB
Channel Imbalance
<0.5 dB
Max Output Current
115 mA
Max Output Voltage
7.8 Vp-p
104 x 62 x 13mm
Outer Material
Brushed Aluminium
Headphone Out
3.5 mm
Battery Capacity / Life
1500 mAh / ~ 15 hours
Recharge Time
3½  hours
The E17K is rectangular shaped with slightly bevelled edges, and well rounded corners. The main body is a two piece machined aluminium outer, and the fitting is practically seamless. On the front of the E17K are and on/off and/or back/exit button (left hand side) and an input button (for source input) on the right hand side. The left hand button glows blue when in use, and red when charging. There is also a monochrome (non-colour) 16 x 30mm screen for viewing functions (the viewing area looks bigger in the photos but this is just the surrounding glass).
Side view - control wheel
Top view - input and output sockets
Bottom view - USB connection

On the left hand side is the digital volume control button (60 steps), and this also doubles as the menu selection and action button.  Pushing in accesses the menu, scroll to select option, push to activate option, hit the front exit button to go back.  Navigation is really easy.  Scrolling has tactile feedback – one click is one selection or volume change.  It really is a robust and easy to use system.
At the top of the unit are three sockets – from left-to-right is the headphone out, line-in/out, and coaxial in.  All are 3.5mm sockets, and all are still nice and firm – even after more than 6 months heavy use.
At the bottom is the micro USB socket for charging, USB digital connection, and also docking with Fiio’s new K5 desktop amp + dock.
Overall the external build is faultless.  It feels really good in the hand – solid and dependable, and has virtually no scratches after around 6 months of heavy use. It is also perfect for stacking – with its flat back – and as far as size goes is the same width as an iPhone 5S (approx. 2cm shorter than the iPhone), very slightly wider than the X1/X3ii (only a couple of mm), and approx ½ cm taller than both.  Using Fiio’s HS12 stacking kit, it is an ideal companion to Fiio’s X3ii.
Opposite side
Rear panel
E17K with X3ii using HS12 stacking kit

Internally, the E17K uses TI’s PCM5102 DAC chip which has impressive S/N ratio and low distortion measurements, but more importantly is quite linear and neutral sonically. Coupled with this is TI’s OPA1622 low-pass filter and OPA1642+LMH6643 in OP + BUF combo. This gives a maximum output power of 200 mW into 32 ohms.
For USB decoding, The E17K uses the SA9027 USB receiver supporting up to 96 kHz/32 bit via USB, and able to also support DSD decoding (using the separate ASIO driver and SACD plugin for Foobar2000).  Via the coaxial digital input, the E17K can decode up to 192 kHz/24 bit PCM input.
So far I’ve noticed no heat build-up at all with the E17K.  Even after hours (driving my HD600s), it’s still cool to touch.
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 Fiio in the past have been notoriously conservative with their published data (a great trait in my opinion), and the E17K is no slug in the power department.
X3ii + E17K makes a wonderful stacked unit
Some of the pairings tested from 320 ohm Zen original to 8 ohm DN2000J
The reality is that using my X3ii as source, and line-out to the E17K feeding the HD600, on low gain (0 dB), at 30/60 volume the HD600 sounds simply sublime – full bodied, well driven, and with plenty of volume headroom left on the digital pot (plus gain if I wanted to use it). I tested this fast switching with my iDSD after volume matching, and there was very little (if any) change to dynamics – quite a feat from a sub $150 DAC/amplifier. With the 600 ohm Beyer T1 it is a slightly different story though – comparatively the E17K still achieves more than enough volume – at between 30-35/60 on the pot, and actually sounds wonderful in isolation – but the iDSD pulls away when switching with slightly more separation and depth.  Would I use the E17K with the T1 if it was all I had – definitely – and I would enjoy it immensely.
On the reverse side, with very sensitive IEMs (and this is testament to the true versatility of the E17K), with the 8 ohm 102 dB SPL DUNU DN2000J, 18-20 on the digital pot is ideal, and there is room to go lower if desired.
So you can see that the E17K has a heap of power on tap – far more than its recommended 16-150 ohm headphone range belies.
As I said earlier the E17K couldn’t be much simpler to learn to use.  As an amplifier, simply plug your source into one socket, headphones into the other, press play on the source, and adjust the volume on the E17K to suit. The E17K has a reasonably low output impedance (<1.1 ohm) so it should suit even the most sensitive earphones. A note on this while I’m thinking about it – I detected no hiss even with the 2000J at normal listening levels, but take this with a grain of salt, because I know that my tinnitus can mask very faint hiss, so I am less sensitive to it than others. 
Input options - include AUX, USB and COAX
Menu showing bass, treble and balance controls
Example of setting the tone controls

The main menu gives you options for:
  1. Treble / Bass controls – more on that below
  2. Balance L/R
  3. Gain
  4. USB charge (turn on or off)
  5. Sleep mode
  6. Volume settings (max and default)
  7. System Info (fw & reset to default)
  8. Display time-out
More menu items - including setting gain and sleep
Menu choices for volume and access to system info
The gain application screen

I mentioned the gain earlier, and Fiio’s stated 0dB / +6dB / +12dB specification is spot-on (measured using loopback).  It’s pleasing to see a decent top end gain utilised which makes it quite practical. Gain does exactly what it says – simply raising the volume by a set amount. And the E17K has a black enough background that raising the gain does not seem to be noticeably raising the noise floor until at very high volumes.  To check this, I used my wife’s super sensitive hearing (she can hear a cat walking on carpet from 10 meters away!).  I used the DN2000J again, set gain to +12dB and had her listen to silence while slowly raising the volume.  Up to around 40/60 on the pot was dead quiet – beyond that the noise floor was audible to her.  But remember, with music playing at +12dB gain and 40/60 volume – hissing would be the last of your problems (it would be deafening).  So good job Fiio – nice clean background.
Gain measurements
+10 to -10 bass and its effects
+10 to -10 treble and its effects

Tone Controls – Bass / Treble
Instead of an EQ or bass boost function, the E17K comes with tone controls. I use EQ quite a lot to correct any imperfections, so I wasn’t sure if I would even use these settings, preferring to use a proper EQ for fine tuning.  How wrong I was. This is probably the feature I like best on the E17K.  Again using loopback and the ARTA software, I measured the E17K’s bass and treble controls which on my unit showed bass +/- range of around 14 dB in each direction.  Treble was just a shade over -10 dB and + 10dB.  What this gives is a brilliant and quick tool for making minor changes to suit your listening preferences.
I love my Adel U6 IEMs, but I find them a little flat in the upper mid-range for my tastes – especially when listening to female vocalists.  Everything else about the signature is perfect – I just want to tweak the upper end.  Applying a simply +4 on the treble gets me perfect sound.  And it is so easy to apply and remove. Brilliant!  Have a bass heavy headphone that you’d like to correct – dial the bass down a bit.  Or if you are looking for a little more bass – just adjust accordingly. Dunu’s new T3 is a classic example – great mid-range, but lacking in fullness and bottom end.  Adding +6dB to the bass transforms the T3 and completes it for me. A ten second job, and for those who don’t generally like using EQ – very easy.
Before and after - Fidue A73
Before and after Alclair Curve (original)
To give you a final idea of the overall effect using both bass and treble controls, I’ve shown the effect on Fidue’s A73 and Alclair’s original Curve – both good earphones that for me fell short of greatness.  For my personal tastes the A73 exhibits quite sharp sibilance at 7-8 kHz, vocals are a little too forward, and I find the bass just a little strong (please note that this is just my preference at play).  Applying -4 dB bass and -2 dB treble transforms the headphones for me – lowers the bass to allow the mid-range to shine more, and tames the sibilance down to a better level. The original Curve was simply too bass heavy, and I’d have liked just a little more in the upper mid-range and lower treble. Applying -4 dB bass and + 4 dB treble, and again – a very different sounding earphone – and very easy to accomplish.
DSD playback (a note)
I did finally get this working – using Foobar 2000 and Fiio’s instructions.  It requires use of some plugins, and just following steps. It isn’t exactly easy or straightforward – and after I’d done it, it clashed with my iFi driver and set-up (requiring reinstallation of those drivers and set-up). So DSD playback will work – but for me this was just something to test.  Performance was Ok – but then again to me there is no real advantage going DSD over PCM.  Again YMMV.
As a DAC
Usage as a DAC couldn't be easier.  No additional drivers needed. Windows simply installs a generic driver, recognises the capabilities of the DAC, and configures accordingly.  This makes it an ideal device if you want to use the E17K with your work PC (they lock ours down so we can't add 3rd party drivers). And the best part of the DAC configuration is that while I can go all the way up to 24/96 via USB (24/192 via coaxial), I also have access to 32 bit rates - and 32/48 is what Darin Fong's Out Of Your Head DSP suite requires for use (so it is perfect for my mivie watching and gaming set-up). I also tried the E17K briefly with Linux (Debian) and it was immediately recognised with full functionality.
Fiio rates the play time on a full charge at around 15 hours, recharge at around 3½ hours, and for my use I’d suggest that time is pretty accurate.
The other feature I haven’t mentioned is the effect on battery life with the X3ii when using the E17K with it.  Normally I’ll get around 10-11 hours with the X3ii by itself. Introducing the E17K extends that to around 15 hours – just simply by taking the load off the X3ii’s amplifier. Nowadays it is rare when I don’t use the X3ii either with the E17K or E11K for this reason alone.


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 E17K perform sonically – as a separate DAC and as a DAC/amp combo?
The first thing I did was to check the linearity of the E17K.  To do this I used a calibrated sound card (calibrated to measure completely flat), ARTA and a loopback. At first glance (and audibly to we mere humans) the E17K measures very flat – practically linear, with a small drop off at both ends.  Expanding this (and my equipment won’t be as accurate as Fiio’s) there is a shallow drop off from about 100 Hz down on my unit and a small bump and drop away in the extreme upper treble.  Not linear I hear you scream – well actually yes it is in terms of audibility.  We’re talking deviation of 0.1-0.2 dB at most, and that is at the extremes of the spectrum where our hearing is least sensitive.  So for all intents and purposes the E17k measures and sounds very linear (wire with gain). So what you are getting is an amazingly neutral amplification not adding or taking away anything.
Linearity of the E17K - frequency response
Close up of the same signal
I’ve stopped measuring distortion (THD / IMD) as I need better measuring equipment to get to the levels Fiio is able to measure.  Knowing their penchant for not overstating things – and looking at the specs for the chips used, I think we can trust the published distortion measurements
So what does this tell us?  Simply that the E17K supplies very linear, and very clean output.  Purely subjectively, it sounds very neutral – no added warmth or brightness I can discern.
For this section I chose to to compare Fiio's own Q1 as a similar but cheaper option, and the iFi Micro iDSD as a much more expensive alternative. The E17K currently is listed on Amazon at USD 124.00, the Q1 at $70, and $499
E17K (USD $124) vs Q1 (USD $70)
Both the Q1 and E17K use the same DAC (PCM 5102) and the main difference is in feature set and amplifier sections. Side by side and volume matched, I actually find very little difference between the two sonically – they both sound fantastic.  Quite linear to my ears with no real added warmth or other tonality – just crystal clear music.
The Q1 is very slightly smaller and very slightly lighter (10g).  Measurements (SNR / distortion) are very similar and power output is also very close with the E17K having he slight edge.  The Q1 brings an analogue volume pot compared to the E17K digital control, and also boasts a quite amazing 30 hour battery life (double that of the E17K).
Instead of the tone controls, the Q1 has a single bass boost switch, no balance controls, no digital input options (other than USB), two stage gain switch, and lower resolution in terms of maximum bit depth and sample rate.
I also have the K5 docking station and desktop amp with me at the moment, and while the E17K (and X3ii, X5ii, X1) dock perfectly, the Q1 appears to get no signal (different pin outs?).
Both units sound astounding for the price – and really this is simply a question of which features are more important to you, and what price you’re prepared to pay.  For me personally I’m prepared to sacrifice a little battery life for the added features and versatility. YMMV with your own personal tastes.
Comparing the E17K with Fiio's Q1 and the iFi Micro iDSD
Portability will be subjective to the users expectations
E17K (USD $124) vs iFi Micro iDSD (USD $499)
I’ll get this out of the way first up. I love my iDSD – it is a fantastic piece of equipment with massive versatility in power output, and a very good DAC in the Burr Brown.  To compare the two is not a fair comparison – but valid for those who may be considering a big step-up.
Sonically the E17K does not have the power output to drive harder to power cans (and it wasn’t built for that either). The iDSD is noticeably clearer, cleaner, has more resolution, and has the ability to play more formats natively.  But the sonic differences (for me anyway) aren’t “night and day”. Both units sound very, very good, and even after listening to the iDSD for a few hours and then switching to the E17K, I am not left thinking this sounds “off” or lower quality,.  Again – both units sound fantastic.
The E17K is a lot more portable, and has more features in terms of digital controls. The iDSD has much more power and much better control of gain setting combos.
For me the iDSD is already end game for my desk-top set-up.  I am not looking further, and even retired my LD MKIV.  However if you take the E17K and add the new Fiio K5 you have a very nice desktop set-up which can double for keeping portability to the fore as well (charging etc).  For those on a budget – the E17K is a compelling choice.
do all my gaming using Darin Fong’s low latency OOYH software for Windows 10.  It is fantastic, bringing brilliant surround sound to my gaming, and since I’ve been using it, I gave away my old sound blaster gaming card to my son. T he software really is that good for immersion and directional queues.  But the software requires at set 32/48 depth and sample rate – something the Q doesn’t do, but the iDSD does perfectly. So does the E17K, and so for the last few weeks the iDSD has sat idle while I’ve put the K5 through its paces as a desktop set-up.  Using the E17K with the E17K and OOYH has been a wonderful experience – so for games on a budget – I thoroughly recommend the combination.


I’ve now had the E17K for over 6 months, and as I slowly started using it more and more, it has become an indispensable part of my portable rig.  How indispensable Brooko?  Well I stupidly dropped it yesterday with a USB cord intact (it slipped, my fault and a freak one-off accident that happened over a very hard surface, and unfortunately the angle of the fall seems to have sheered something in the USB port). Without question, I’ve immediately set in motion the purchase of a new unit.  I have other DAC/amps and DAPs with DAC functions that could substitute – but really they can’t.  And that is a hint at the true value of the E17K – once you get used to the feature set, and combine it with the excellent sonics, it becomes an indispensable component. I simply do not want any other unit – I want my E17K.
The E17K brings very good size, weight, power, and sonics together in a very budget friendly package. As a stand-alone portable amp (forgetting the DAC function) you have a fully featured amplifier with true versatility, and definitely worth the current asking price.
Add in the excellent DAC, connectivity options and the E17K becomes a steal at the price.  If I went back to my original list, the E17K ticks every box on my list, and if adding the K5 desktop amplifier/dock – may well be end game for many people.
E17K docked to the new K5
X3ii, E17K and Adel U6 - wonderful combo!
All in all, I would recommend the E17K to both audio starters and the even the more experienced without question.  For what it delivers, it is incredible value for money. Like the HD600, it is another piece of audio gear I simply cannot imagine being without.
Congratulations Fiio – this is simply one of the best devices you have ever released.  Thanks again to the Fiio team for the chance to write about your products.  This is one of the few devices I wouldn't change at all.
I just have it at full line-out (non-adjustable).  Use the E17K for all your volume and EQ tweaks.  Will be interesting to see how you like it.  You obviously can't get into a lot of fine tuning, but as a quick and easy tweak, I love it.
Brian Reid
Well what can I say about this. The sound is excellent, I cannot get away with how going from the E17K headphone output, unplugging the L17 lineout cable and listening to the X3 II on the same song can sound so different, I had the EQ set to flat on the X3 II and Gain to Low, so changed them back to my USER setting and Gain to High and it still sounded flat compared to 0 gain and some base and treble on the E17K.
I am not really a fan of the stacking I have to admit, I bought the HS12 and I have a silicone rectangle between them at the moment, I assume thats what they are for, rather than the stick on feet which are also prt of the kit, but it does move about when you have to push buttons and since they are different sizes it does feel a bit homemade. It would be nice to maybe have a double sided case with access to both sides but this would probably end up being quite a bulky item.
I also see they have changed the lineout cable available with the E17K to a smaller item, I have not tried that to see the sound difference as I bought the L17 and would be sad if it sounded the same.
Outstanding review @brooko, based on your assessments and clear logical reasons I received mine today, and am truly impressed. I've got a very ordinary android phone, and with this e17k it truly sounds better than my aging, needs replacing, iPod. I looked at DAPs but figured this would be more flexible, and am seriously impressed by the sound quality. Just hoping this isn't the beginning of a slippery slope, finding out what a small investment can yield in sonic rewards. Nice one.


Hey. Where can one find one of these models new?
I am looking to get a second one and having hard time find new one on amazon/ebay in the usa.
The e17K is my prefered DAC, compared to the many others Fiio has, as it has digital bass and trebble EQ.
realy makes my Vmoda full sized headphones roar.
None of the other DACs seem to have bass/trebble addjust.