FiiO E6 Portable Headphone Amp Review

 fiio e6 main FiiO E6 Portable Headphone Amp Review

FiiO is a Chinese audio company that should need no introduction by now. Among all the headphone amp, soundcard, and cable manufacturers they are probably the one with the best bang-for-buck ratio, consistently delivering high quality products for a very fair price.

Their older tiny portable amp model – the E5 – is still quite popular among users, and seriously well performing for its $20 price tag. Let’s see if FiiO could up the ante a notch with the E5’s recently introduced successor, the E6.

  • FiiO E6 Specs
  • Output power: 150mW into 16 Ohm, 16mW into 300 Ohm
  • Frequency response: 10Hz – 100kHz
  • SNR: >95dBA
  • THD: <0.0009% (10mW)
  • Battery: Li-Ion, ~10h run time, 2h charging over USB (5V/500mA)
  • Size: 41×40.2x9mm
  • Weight: 16g
  • Accessories: 2x 3.5mm-to-3.5mm cables (10cm with angled plugs, 80cm with straight plugs), USB charging cable, 2x removable clips, printed manual

Accessories, Design, Specs

The E6 comes with two 3.5mm interconnect cables and a standard Mini USB cable for charging. The audio cables appear to be of solid build quality, with sturdy molded connector housings and gold plated plugs. The longer 80cm cable has straight connectors, the shorter 10cm one has right angled ones.

There are also two shirt/pants clips in the box, made of transparent plastic. They don’t seem overly sturdy, so it’s probably good that FiiO packed a spare. Personally, I don’t intend to use the clips, so I’m grateful that FiiO made them removable. The non-removable clip on the older E5 always bothered me a bit, since it just adds to the size of the amp.

Housed in glossy plastic, the E6 doesn’t have quite the same haptic appeal as the metal-clad E5. The E6 is much lighter, though. Dropping it from a meter or two onto a hard floor shouldn’t damage it. It certainly feels quite solid and well built. Speaking of damage: the E6 scratches very easily. I wish the housing would be made of matte plastic instead of the ultra-glossy one FiiO chose. Not only would it look somewhat classier, it also wouldn’t show every tiny scratch. They also shouldn’t have painted the plastic buttons and the cut-out edge with chrome paint – it looks cheesy, faking a material it actually isn’t made of. That’s so 1990s. Maybe a fitting silicone case for the E6 would be a nice addition for persnickety folks.

However, these are just nitpicks, not detracting from the fact that the E6 is overall a quite fetching tiny monolith. I find its design certainly more appealing than the E5’s. The location of the power- and volume buttons is also better on the E6, since the in- and output jacks aren’t getting in the way of operation.

The volume control is excellent on the E6. It’s a 64 step digital control, with very smooth, linear step transitions – a definite improvement over the E5’s rough 32 step control. Contrary to many analog volume controls (as found in very expensive amps as well) there’s no dreaded channel imbalance or crackling to be noticed at any volume level.

Opposite the volume control is the multi-function slider that controls the rest of the E6’s functions. Holding the slider for three seconds turns the amp on or off; sliding it quickly toggles the various sound modes (personally I would prefer it the other way round – short on/off, long mode change). Those modes are called flat/default, EQ1, EQ2, and LO 2V.

EQ1 and EQ2 are bass booster settings. EQ1 gives about 8dB boost centered around 80Hz, EQ2 gives about 4.5dB. EQ1 is unfortunately very muddy and overwhelming sounding. I would not even use it with bass-light phones like the Phonak PFE 112, since it takes away much of the clarity and detail. EQ2 is more subtle sounding and usable in certain situations. However, I still prefer the old E5’s bass boost to the E6’s EQ2 by a bit. The E5 gives about 3.5dB boost centered around 50-60Hz. Although subtler, it sounds noticeably clearer and punchier than the E6’s two settings. Well, it’s simple – don’t get the E6 if clear, punchy bass boost is your main requirement. For this application I would strongly recommend the Digizoid ZO or the Headstage Arrow instead, although they are not in the same price range.

The other available option, LO 2V (Redbook standard line-out 2 Volts?), is probably meant for ‘hot’ sources with more powerful outputs than average MP3 players, I assume. Neither the manual that came with the E6 nor FiiO’s website give any real explanation for this setting. What it does is lowering the amp’s volume by a few decibel – presumably already on its input side, to prevent clipping. I don’t really use a source that would need this feature, but I’m sure there are some devices out there that could benefit from it.

The various settings are visually represented by two LEDs, visible on the back of the E6. No LED light means flat response, red means EQ1, blue means EQ2, and purple (mixed blue and red) means LO 2V. There’s a separate blue LED indicating when the E6 is turned on. It is located inside the cut-out corner triangle and reflects from the chromed plastic. That’s quite a nifty design idea, I like that.

A slight flaw with the multi-function slider implementation is the volume button lock function. Sliding into lock/hold mode is fine, but sliding back and releasing it almost inevitably changes the EQ setting. One would have to be very careful to slide it just so far as to not trigger function cycling. Personally, I find the button lock on this amp isn’t needed, so I never use it – and thus have no issues with it.

Powering an amp on and off seems to be something trivial, but it is actually faulty and possibly dangerous on many devices. Many amps start up or shut down with a loud audible click or pop. This means that a strong voltage spike is sent into the headphones drivers. Not only might this sudden induced movement damage the drives, it might also be painful to the listener’s ears. FiiO got that widespread issue perfectly right in the E6. Powering on and off is completely silent, not even the faintest click can be heard.

Battery life of the E6 is quite good, considering its diminutive size and rather respectable output power. FiiO claims about 10 hours of usage, but I get even more than that. The battery is charged via a standard Mini USB port, it takes about two hours for a full charge. It can be used while charging, but that depends somewhat on the quality of the USB port. Some improperly shielded circuits might add some background hiss or hum, while others don’t. The E6 however is less susceptible than many other USB-charging amps to such issues.

FiiO also took care of proper EMI/RFI shielding. The E6 doesn’t pick up any GSM or Wi-Fi signals, not even with a cellphone or router right next to the amp.


So what does the E6 sound like?

It’s simple – it doesn’t sound like anything. It’s a perfectly neutral, linear amp, with no ‘character’ of its own. It’s not ‘cold’ or ‘warm’ or ‘bright’ or ‘dark’ sounding. It delivers the input signal to its output without adding or subtracting anything. This is basically as good as it gets, no matter what price range we’re talking about (tube amps and their often pleasing harmonic distortions excluded). In volume-matched listening tests I could not distinguish the E6’s output from a Sansa Clip+, a Headstage Arrow, or an Echo AudioFire 4.

So if everything sounds the same, what’s the use of the E6?

Obviously, the E6 can make quiet sources louder, to drive headphones with higher impedance rating and/or lower sensitivity. My real-world example is the aforementioned Sansa Clip+. It’s not an overly loud player to start with, made quieter through the Rockbox firmware, and finally even quieter because I use Replaygain on my audio files. It’s an excellent performing player with that configuration, but one needs some fairly efficient phones to get acceptable sound levels out of that thing. Quieter IEMs like the Phonak PFE 112 or Hifiman/Head-Direct RE0 definitely need an amp to reach acceptable listening levels in this setup.

Of course, using a more powerful player such as a Cowon or similar, one doesn’t really need to worry about volume levels – unless one wants to drive some 300 Ohm phones or the likes. Then the E6 would certainly help a bit. Maybe it wouldn’t go to ear-shattering levels, since the amp is not über-powerful – but it should be perfectly acceptable for normal listening levels. Up to 150 Ohm or so, the E6 should handle virtually everything with ease.

Either way, it’s not really useful going by numbers and specs alone, since every phone handles differently. Overall, one does get about 8-10dB volume gain from the E6, which is about 2-3dB more than the older E5 delivered. To human ears, in general the E6 should go up to about twice to three times as loud, compared to an unamped source.

The less obvious – but quite important – issue a well designed amp can fix is flawed sources with high output impedance on their headphone jacks. Faulty devices like Realtek onboard sound cards, the Hifiman HM801, the Sony A840 series, or Archos Gen8 internet tablets have output impedances ranging somewhere between 10 and 30 Ohm. Those devices cannot drive multi-armature IEMs with crossovers properly. This flaw is more or less audible with most of them, making multi-armature IEMs generally sound muffled, veiled, and lacking treble.

Using the E6 with its less than 1 Ohm output impedance with those faulty sources can make a veritable ‘night and day’ difference in the way phones like the Earsonics SM3, Ultimate Ears UE11, or others sound. The E6 restores the original electrical signal and fixes these impedance issues for good. It doesn’t make the sound ‘better’; it simply makes it ‘as it’s supposed to be’. This is no issue with non-broken players like Cowons, AMS Sansas, or current generation iPods, so one wouldn’t need an extra amp for this specific fix regarding multi-armature IEMs. Also, dynamic driver IEMs don’t have this issue at all, no matter how high the output impedance of a player.

Another issue – also related to impedance and sensitivity, among other factors – is background hiss with combinations of certain sources and headphones. The E6 is on the very well behaved side and can fix this issue for most applications as well. Only with ridiculously sensitive IEMs of 120dB/mW and above (like the UE11 or Shure SE530) there is some faint background noise audible with the E6 – and then only at louder listening levels. With less sensitive phones at sane volume levels the E6 is generally dead silent.

Other variables – channel crosstalk, intermodulation and harmonic distortions, dynamic range, etc – are all fine and within specs. There’s really not much to say about any of them. Measuring instruments might show some pros or cons in graphs, but human ears generally can’t hear those things.


The Fiio E6 is a very high quality portable headphone amplifier. Of course there are always some ‘audiophile’ fractions which would never admit that a $30 amp can match and even surpass a $300 one, but that’s how it is. The E6 performs as well as the most expensive amps I’ve tried, and surpasses many of them in several performance aspects. If the E6’s circuitry would be put in a fancy brushed aluminum housing and it would be made in the USA or Germany, one could most definitely slap an upper three-digit price tag on it, and nobody would complain.

FiiO might not have built the loudest, most powerful amp – but they built one with all around excellent performance and no apparent technical flaws. I know quite a few portable amps that cost ten times the price of the E6, but can’t drive multi-armature IEMs properly, can’t adjust volume levels without crackling or channel imbalance, don’t have a flat frequency response, or can’t turn themselves on without almost blowing the attached phones’ drivers due to loud clicks and pops. The E6 has none of these all too often experienced flaws – and it’s also tinier and more lightweight than most other amps, making it quite bearable to carry additional bulk around.

If you do need an amp in your setup to fix any of the shortcomings I described above, the FiiO E6 should be your first choice. It would be silly to pay more while possibly getting less performance quality. If bass boost is your main requirement, there are better choices than the E6 (the Digizoid ZO for example), but as a standard headphone amp the E6 does everything by the books.

Congratulations, FiiO. Once again you have shown how to do things properly, for the right price.


  • Flawless audio quality, neutral and linear, no distortions, good SNR
  • Drives any low-to-medium impedance phone with ease (some high impedance ones, too)
  • Very low output impedance; can handle any multi-armature IEMs properly
  • Precise 64 step digital volume control, no channel imbalance or crackling
  • Very little background hiss (only slightly audible with ultra-sensitive IEMs at louder volume levels)
  • No clicks/pops at turning on/off
  • Properly shielded, doesn’t pick up any cellphone signals
  • Decent battery life considering the size
  • Tiny and lightweight
  • Removable clip
  • Very inexpensive, considering its high quality performance


  • EQ1 bass boost sounds muddy and overwhelming (EQ2 is more subtle)
  • Button lock function poorly implemented, might change EQ setting when released
  • Glossy plastic housing scratches easily


The FiiO E6 can be bought from MP4Nation, and probably a slew of other vendors.



shotgunshane on October 15, 2011 1:23 PM

Very nice review. I like the way you explain the purpose and uses for external amps in a very straight forward manner.

Matt on October 15, 2011 6:04 PM

i really appreciate your objective stance on amps without the audiophile BS. just wondering though, would there be any real benefit to getting this e6 to replace my e5, for any purpose or reason?

Martin Sägmüller on October 15, 2011 6:12 PM

The E6 is certainly a decent upgrade over the E5 in several aspects (output power, hiss, shielding, etc). It really depends on the phones and/or player you are intending to use it with.

Sang on October 15, 2011 7:35 PM

I had actually read that EQ1 boosts the bass frequencies by 4dB, and EQ2 boosts the upper frequencies by 4dB in addition to the bass boost from EQ1, which creates a more balanced sound. I’m not sure about the exact numbers, but from my perception of my E6, that seems to be true that the bass levels actually do not go down in going from EQ1 to EQ2. I could be wrong.

bababooey on October 15, 2011 8:56 PM

RMAA or didnt happen.

Johnny on October 15, 2011 8:57 PM

Nice and simple review. I may consider picking one up. Clear and neutral. Just how I like it.

fb2k on October 15, 2011 9:08 PM

hi, would the E6 improve the battery life of my mp3 player when using IEMs such as re-262 ?

Martin Sägmüller on October 15, 2011 9:36 PM

Sang, that’s incorrect. There is no treble boost on the E6. You can check the various frequency responses in my RMAA tests linked below.

Bababooey, RMAA doesn’t tell the whole story, and people tend to misinterpret the results. That’s why I don’t post them in my reviews. But since you asked so politely:

FB2K, I doubt it will save a noticeable amount of battery life with these IEMs.

IonutIT on October 16, 2011 9:18 PM

Quick question. If I hook this up to an Android Phone and a pair of headphones with play/pause/ff/rev controls, will they still work? I mean clicking to pause or to answer a call? Will the click register through the amp and into the phone?

Martin Sägmüller on October 17, 2011 8:26 AM

IonuIT, no, unfortunately not. Like every other amp I know, the E6 only has a regular 3-pin connector.

Aspect on October 18, 2011 4:23 AM

I run a sansa clip+ with a pair of re0s, would I need this? I don’t really notice the quiet factor. I listen at -45db most of the time.

Chris C. on October 25, 2011 1:26 PM

great review. This amp sounds like a winner.

MarvintheMartian on November 3, 2011 4:43 AM

I’m very happy with my E6. Definitely a worthy upgrade from the E3 and E5.

Sal on November 16, 2011 12:42 PM

just wondering if this would be a good pick up for the senn ie8′s?

Martin Sägmüller on November 16, 2011 1:24 PM

Probably not. The IE8 are easy to drive and sound just fine out of any MP3 player.

Nan on November 26, 2011 7:24 PM

I currently use a 3.5mm to RCA to play my iPod through my car stereo but I find that at full volume on both the iPod and stereo, the volume is significantly lower that when playing a CD. Could I use this to raise the volume?

Martin Sägmüller on November 26, 2011 8:28 PM

Yes, definitely – the E6 should make it at least twice as loud.

Arashi on December 2, 2011 11:20 AM

Cowon players do have issues with bass roll off due to what appears to be coupling capacitors on the headphone out path. The amp fixes these sort of silly things.

phil on December 5, 2011 10:59 PM

considering you said this is compared to higher 3 digit amps..
and if u dont mind me asking martin is it worth getting your highly recommended headstage arrow or would this do jus fine? not considering the price tag and the additional bass boost.

phil on December 5, 2011 11:06 PM

also what do you think about the new FiiO E10 compared to the E5?

Martin Sägmüller on December 6, 2011 12:33 PM

The Arrow has more output power and can drive high impedance phones louder. If you don’t want to drive 300 Ohm phones to ear splitting levels, the E6 should do just fine.

The E10 is an USB sound card, it can’t really be compared to the E5/6.

ASanders on December 22, 2011 5:53 PM

Hi Martin brilliant review and thank you.Could you help me with one question please.I have a Sansa Fuze (Rockboxed)and recently I have purchased some Sennheiser HD25-1 11 headphones .Because I rip my own vinyl which are more than not at a lower level than most cds the recordings are a little quieter.I am missing that oomph .I dont want anything to be boosted apart from the volume .With you mentioning the impedance and sensitivity I was wondering whether the E6 will do the trick.Impedance:70 Ω Sensitivity:120 dB/1V.Thank you in advance Adrian.

ASanders on December 22, 2011 5:56 PM

Ooops What I meant to say was.
Because I rip my own vinyl the music is quieter than most cds the recordings are a little quieter.I am missing that oomph .

Martin Sägmüller on December 23, 2011 1:29 PM

ASanders, I would suggest you analyze your files with Replaygain – both Rockbox and the Sandisk firmware support it. Replaygain might be enough to boost the volume (without alteration to the dynamic range or distortions, of course), so you might not need an amp after all.

Henry on February 10, 2012 7:35 AM

Awesome review! Helped me to go ahead a decide to buy one in the end. I have a Sony NWZA865 havn’t noticed any difference with my cheap headphones but was a night a day difference when using my dad’s HD600s. I have some ATH ESW9′s in the post and was wondering if my E6 will make any difference, guess I should wait and find out but would like to hear your opinion. Thanks.

Henry on February 10, 2012 7:38 AM

Of course I know it really all just boils down to impedance.

Oliver on February 15, 2012 6:13 PM

I got a question for you guys. For my TV to headphone setup it more or less looks like this.

TV -> RCA Cable -> RCA to 3.5″ adaptor -> male/female 3.5″ extension -> Headphones

The problem is that sometimes the volume depending on the source (Channel, Game Console etc.) is sometimes too low or too high. If I do this

TV -> RCA Cable -> RCA to 3.5″ adaptor -> male/female 3.5″ extension -> FiiO E6 -> Headphones

Will that enable me to change the volume on the E6? I can’t actually change the volume output out of the TV from the RCA connections. As far as I’ve been able to figure out, it’s a fixed volume. I’m not looking for anything complicated and just thought that putting the FiiO before my headphones would help me control volume.

Martin Sägmüller on February 16, 2012 1:30 PM

Oliver, yes, you can change the volume on the E6. But instead of an amp you could also get a simple in-line volume control for that task. Something like this –

Henry on February 17, 2012 1:02 PM

So…will ESW9′s with E6 make a difference or not? Also is an L5 line out worth it? Thanks

Martin Sägmüller on February 18, 2012 5:05 PM

Considering the ESW9 are 42 Ohm and 103 dB/mW, I doubt you will have problems driving them with any halfway decent player. So, the E6 probably won’t make a difference.

Henry on February 19, 2012 12:55 AM

Good to know, thanks for replying. So do the (L3,L5,etc.) line outs make a difference and which portable headphones would you say pair up best with the E6? I’m expecting you to say HD25′s or somthing. Thanks again for answering my questions, portable listening is kinda a new interest for me so really good to get feedback from someone who knows what they are on about. I also read a good bit of your one million page essay about headphones low end to high which was fantastic.

Henry on February 19, 2012 1:12 AM

Or I guess beyerdynamic DT1350 at 80ohms would need to be amped… I using a Sony A-Series.

Bill Knotts on March 30, 2012 11:45 PM

Is it possible to overcharge the battery on the E6 by leaving the usb cable connected to unit and computer permanently?
Should I disconnect usb cable when red charging light goes out?
thank you
Bill K

Nikola on April 2, 2012 5:50 PM

Great review – simple, clean and neutral. Thanks!
I have 3 decent headphones sets – Klipch, Incase & Audio Technica. All of them work fine with my iPod Touch and I don’t think I need an amp for them. But recently I purchased another set – AKG K172 and they are incredible quiet!! Really really quiet! Flat, no bass whatsoever. Before I retun them, I was just wondering should I expect any significant improvement with the E6? Thanks again.

Martin Sägmüller on April 6, 2012 12:37 AM

Bill – no, you can’t overcharge it. When the red light goes out it stops charging.

Nikola – I’m sure the K172 would benefit from it. I had some K141 which were a bit hard to drive too, but a quality amp made them sing on the go.

Brandon on April 19, 2012 7:47 PM


I currently use a Fiio E5 as a bass booster for my record player set up because it sounds a little lacking in bass.I run my record player (it has a built in pre-amp) to my surround sound via a line in cable and use the E5 to add a little bass. Would the E6 give me significantly more bass? The review says that EQ1 on the E6 gives TOO much bass, so does that mean it gives a lot more than the E5?

michael on May 4, 2012 3:00 PM

I just bought this e6… I read the power output for 16 ohm impedance is 150 mw… I use IEM soundmagic e10 and maximum input for this IEM is 20 mw… will this amp damage my IEM? thanks in advance

henrymil anderson on May 9, 2012 4:45 AM

hello sir will you help me to decide between e6 and fiio e11. im using sennheiser hd-419 and a nokia n8 12 megapixel smartphone.. im having a hard time deciding and reading reviews and choosing between the two amplifiers. im looking for a more balanced sound and yet powerful amplifier to drive my sennheiser hd-419.. im not looking for skullcrushing bass as the 419′s bass is good enough and needed just a little im wondering which of these two amplifiers will you reccomend that have a more balanced sound and gives more power, clarity or soundstage to sennheiser the equalizer of these 2 amplifier just gives bass boost or it gives treble as well….which one will you reccomend the e6 or the e11? and lastly im confused..a smartphone has an equalizer and a portable amp has an equalizer, when playing the headphones which equalizer that the headphones uses , is it the eq of the amp or eq of the smartphone or both (if the headphone bypasses or uses the eq of the ampli then the eq of the phone will be useless)im confused.. thanks and more power. sorry for the many questions and the inconvenience, i just want to be sure on my purchase and will not make a mistake on which portable amplifier im going to pair with my hd 419…

A J on May 26, 2012 9:02 AM

Hi. Do you know if I can use this between my line out but low output portable Numark turntable PT 01 and my lovely but low output t-amp super to get a little more juice out of my LPs?
Anyone done a comparison chart between the various Fiio amps?? That would be mighty useful.

Lewis on July 24, 2012 10:55 AM

Thanks for the excellent review. I didn’t understand the instruction manual and was almost ready to return the unit.

Jay Quiambao on August 10, 2012 9:36 AM

Do i really need this (FIIO E6)if i have a HTC One X and my headphone is Audio Technica ATH-M50??? Is there any difference??? Thanks

Cathy on September 1, 2012 10:54 PM

I just purchased the E6. I had it plugged into my computer all night. The red light is still flashing. I can get the blue (and red)light(s) on and use it if I leave it plugged into the computer. When I unplug it there are no lights.
Am I doing something wrong? It’s had at least 3 hours to charge while I’m using the computer. Thanks for any help.

James on October 17, 2012 9:05 AM

Nice review but I think the E6 does have a bit of coloration to it. On EQ 2 (the blue light) it boost the treble some and gives the mids a bit of warmth along with the add bass and EQ1 is really warm with enhanced bass. Its a great amp for the price.

The E11 has more of a flat balanced response and a little cleaner over all sound signature as you’s expect for about $35 more.

Hoangtung on October 25, 2012 3:47 AM

Hi, should I buy E6 for my HD558, I new in this field, pls help:)

akheel on July 5, 2013 4:54 AM


should i get the fiio e6 or e11 to drive my grado sr325is via iphone.

Comments Closed. Please continue the discussion in the forums