FiiO A5 Review – Portable Headphone Amplifier

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The FiiO A5 is an amazing combination of good headphone sound reproduction, build quality, and fighting power at a very affordable price. It is an upgraded version of two of our customers’ favorite amplifiers, the FiiO E12 and FiiO E12A, with the “E” series replaced by the “A” series. In terms of sound quality, the A5 is now rated higher than the E12, the latter being more affordable.

The amplifier is one of the company’s portable headphone amplifiers, and like its other products, it’s well built. The controls work well, the volume control increases the volume smoothly, and the sound quality is good when playing lossless audio formats. Power and volume are excellent. If you want to boost the volume of high-impedance headphones or improve the sound quality of low-impedance headphones, this is the amp for you.

FiiO A5 Portable Headphone Amplifier Review

FiiO A5 Specifications

AMP: MUSES02 & LME49600 | Output power: ≧800mW/32 Ohms, ≧150mW/300 Ohms | Total harmonic distortion + noise: <0.002 | Signal to noise ratio: ≥115dB | Output impedance: ≤0.3 Ohms | Channel unbalance: <0.3dB | Output voltage: 14.96Vp-p | Output current: 250mA | Battery: 880 mAh (13 hours) | Charging time: <3 hours with 2A charger | Dimensions: 124mm x 65.5mm x 14.5mm | Weight: 168g


The package contains various things. It comes with some expected items such as a MicroUSB cable for charging, a small case, and two different-sized rubber rings to connect the player to the amplifier. However, it also comes with a few unexpected items, such as a silicone pad to prevent scratches when the two devices are used together. The package also includes a very nice short cable with two 3.5mm plugs, a manual, and a warranty card.

Design & Ergonomy

The amplifier is made of high-quality steel and, with the exception of the power button, is solidly assembled without any rigidity or creaking. FiiO may not make fashion statements, but its units are among the most memorable and reliable portable hi-fi products on the market.

The A5 inherits many features from its predecessor, the E12, but it’s essentially the same device. Why change something that looks and works so well?

On the left end of the FiiO A5, you’ll find a micro USB port and a bass boost switch, which boosts bass by 6 dB. Everything else is clustered on top of the unit, including the volume control, amp mode switch, and 3.5mm jacks (input and output). There is also a badge on the front panel and two indicators showing the battery status and amplifier operation.

Charging the battery takes about 3 hours at 5 volts, and the amplifier operates for about 12 hours at medium volume.


The A5 uses a combination of MUSESO2 + LME49600 chips, a solution that results in surprisingly low distortion. However, the amplifier circuitry does not include a DAC, so only one analog source can be connected to the A5.

The FiiO A5 can be connected to headphones up to 300 ohms impedance. Most people use a pair of headphones, but for portable audio devices with a load impedance of 32 ohms, the maximum headphone output is 800 mW.

Channel separation is an impressive 75 dB, and the signal-to-noise ratio is comparable to that of desktop computers (over 115 dB). With its low noise floor and near-zero output impedance, the A5 isn’t necessarily suited for use as sensitive headphones. Its niche is demanding full-size dynamic headphones and in-ear monitors.

All that sonic brilliance is encased in the usual clean, all-metal housing. The battery is built-in, and there’s no removable cover, so everything is seamless. Its capacity is 880 mAh, which is enough for 12-13 hours of music listening.

Sound Quality

Many of today’s portable amplifiers have good power reserves, and most headphones are very sensitive and do not need much power. For this reason, it is not recommended to buy an amplifier and place it between the source and the headphones to alter the original signal as much as possible. While this is common in some cases, and amplifiers can improve the sound quality of your headphones, the main purpose of an amplifier is to provide power to the headphones so that they can reach their full potential. If you are happy with your headphones, you should only buy an amplifier if you need more power.

Instead of talking about the three frequency bands of the A5 and how they sound, I will describe how it changes the sound of some very sophisticated headphones, which in this review are Sennheiser HD 660S and, to a slightly lesser extent AKG K701.

When listening with an iPhone or Android smartphone, the FiiO A5 shows the headphones’ full potential. With the Sennheiser HD 660S, the sound is more immersive, very clean, detailed, and even smoother – all the small details are gathered into a huge beautiful auditory image that is a pleasure to listen to. The AKG K701s, on the other hand, sounded a bit warmer and more compelling to the ears of a regular music consumer but has some of its analytical components reduced.

With the A5 amplifier, the bass in many neutral mid-range headphones, such as the AKG K72 and ATH-M50X, became deeper and more textured, with better dynamics. This improvement is reflected in the depth of the soundstage, with a small amount noticeable in the low and midrange. This effect is more pronounced in more high-end headphones like the Beyerdynamic 770 DT 250 Ohms but doesn’t make much difference in the less sensitive IEMs.

There is also a change in sound that appears in most headphones, although it is not as pronounced. Due to the slight softening in the mid-range, the amp has shifted the focus of detail to the emotional elements of the material, mitigating some recording flaws. When the bass-boosting feature is activated, the bass becomes more powerful; thus, the sound warmer and the overall characteristics more vibrant.

There is a nice depth in the mid-bass range. It’s very selective. It’s impossible not to be drawn in. What’s especially nice is that you can listen to any kind of music because the bass is smooth. You can use the EQ if you want, but the already standard bass response is pleasant to listen to.

The midrange is accurate, clean, without clutter. Vocals are not lost among any instruments, from brass to guitars. Even genres as complex as classical, jazz, and orchestral music are not messed up.

Interestingly, unlike the E12, high frequencies are not a problem anymore. This portable headphone amplifier has a high-pass filter that removes excessive reverberation and harshness from the sound. For this reason, audiophiles with perfect ears may have problems with high frequencies, considering the highs stiff. However, most music lovers will be more than happy with the filtering.

The treble response of the FiiO A5 portable headphone amplifier is slightly softer than its predecessor, the E12. The difference isn’t very significant, though, so if you already own the E12, there’s no need to rush to upgrade.


Overall, the FiiO A5 is a great portable amplifier for listening to music on headphones. It is an absolute monster that produces plenty of power and can handle almost any load. Obviously not everyone will need it, but if you want to listen to some pretty powerful headphones while moving from place to place without needing a stationary DAC/amplifier, the A5 is a great and very affordable solution to that problem.

The A5 sound should complement any in-ear or full-range headphones on the market. They set the tone and maintain the quality with which the engineers designed the headphones. As far as portable use is concerned, the FiiO A5 is the perfect amplifier for the iPhone, but it works just as well with other smartphones and players.

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