The FiiO E6 is a low-cost product. Like the E5 before it, this sub-£20 headphone amplifier is far, far cheaper than almost all of the competition. Its capabilities are also less than a desktop headphone amp. It outputs 16mW when under a 300Ohm load (a common impedance for big, on-ear headphones), where FiiO's own E9 desktop amp outputs more than 80mW under the same strain.
This diddy amp doesn't have oodles of power at its disposal, but the reasons why are obvious. The E6 is powered by a tiny, light lithium battery, and if it was to attempt to recreate the power of a home amp, that juice wouldn't last long. For most uses, it wouldn't need such power anyway - this is an on-the-go device, and very few people use truly high impedance hi-fi headphones when out and about. Even fewer sensible ones.
What the FiiO E6 does supply is that little extra bit of power the average headphone amplifier, and, yes, it'll boost the volume beyond the capabilities of most media players if necessary. The effect upon the subtler sonic qualities of whatever you're playing varies a little between headphones used, but having tested the E6 with around 10 sets, trends to emerge.
It doesn't send to have the soundstage-enhancing effect of a more powerful amplifier, but does tighten-up the bottom end a bit. This can improve coherence in music, and naturally gives bass response a quality boost. Some sets also showed an increase in dynamics, giving the impression of an overall more "vivid" sound.
This is what it sounds like without any of the EQ settings engaged, using the FiiO E6's vanilla mode if you will. With a prod or three on the power slider you can access the unit's three additional modes, -3dB, 3dB and 6dB. The original FiiO E5 only had the single 3dB setting.
The two signal-boosting modes can roughly be described as bass boosts. They aren't hugely invasive, instead adding a little warmth to the low-end and low mids. We found that the 3dB setting muddied the sound ever-so slightly, making the treble sound a little recessed, but the 6dB setting pumps-up the high-end as well as the bass - although the figure is doubled, the bass doesn't. The sound scales-up naturally, leaving no bass bloat, as long as there wasn't any originally.
What the FiiO E6 does better than a media player here is equalisation without colouring the sound in an unnatural way. That's not to say some headphones don't sound better on the EQ-free setting, but there's none of the ugliness many digital EQ systems introduce.
The big surprise of the FiiO E6, though, is that we found the -3dB setting to be the most useful. You might assume robbing the sound signal of power would leave it sounding weak and brittle, but it comes in very handy when trying to tame a pair of earphones with just too much bass - commonplace in affordable 'phones. This setting can also help relax treble frequencies with too much fatiguing "zing" or harshness.
The setting to employ all depends on the sonic personality of your earphone of choice, but they can all benefit in some way from the FiiO E6. And experimenting with the various EQ modes is in itself fun.
As an introduction to headphone amplifiers, or as an affordable partner to a more expensive at-home unit, the FiiO E6 is perfect. It's cheaper than the SoundMagic A10 and NuForce Icon, and while it may not have all the benefits of a more powerful amp, it's much more convenient. For existing FiiO E5 owners, the extra two EQ settings are enough to justify a purchase if you're not satisfied with the current bass boost. When testing the E5 we also heard hiss in some setups, but there was none at all here. The sound quality and feature niggles of the original are all-but eradicated.
An update to the popular FiiO E5, the E6 offers a very affordable and portable headphone amp solution that offers some of the sonic benefits of its more expensive rivals. It's not clad in metal like its predecessor, but it's smaller, lighter and altogether more stylish. This is the perfect product for those new to headphone amps, or those with a cynical view about them. And even if you're not convinced by its standard setting's benefits, the EQ modes alone justify its cost.