The FiiO E6 is small headphone amplifier designed to improve the listening experience from personal music players and smartphones. With a couple of equalisation settings, the E6 can enhance the bass range to counteract the high-frequency tendencies of digital compression.

In the box, there’s the E6 itself, two clips for attaching the E6 to clothing, a USB charging cable and two stereo 3.5 mm cables, 12 cm and 75 cm. For hooking up iDevices, an Apple connector-to-3.5 mm jack is available to buy. There’s also a small instruction manual.

The E6 is 40 x 40 x 9 mm, approximately the size of an Apple Nano. The main features are a mini-USB port for charging, two 3.5 mm stereo sockets (one in, one out), a volume rocker and an on/off slider. There’s a small LED on one side, but until the E6 is powered up, you might mistake it for a reset hole.

The E6 is quite light as the case is plastic. Coincidentally, the finish was a good match for from my Sansa  player and could easily be mistaken as a complementary accessory, but clearly that feature depends on your particular mp3 player!

Sliding up the on/off switch turns the E6 on, with a blue LED illuminating the silver corner. The volume rocker switch turns the volume up and down and as this is an amplifier, it’s possible to exceed the volume of the original device, so mind your ears. The battery life is given as around 10 hours which would be in line with my experience of the E6.

On the back, there’s a small pinhole LED showing the equalisation – off, red, blue and lilac. Each further upwards push of the on/off switch steps through to next setting. According to the manual, the four settings are equalisation off, 3 dB boost, 6 dB boost and -3 dB boost, i.e. reduction, but the effects are more subtle than simply amping up or amping down.

Generally, the equalisation boosted the bass while reducing the treble and while my personal preference was for the first setting, both were very acceptable. The equalisation was done well, in that while the balance of frequencies was being adjusted, the clarity was still there. Although reduced in significance, the higher frequencies weren’t muddied and the overall impression was of greater warmth.

A small amount of background hiss was only noticeable between tracks when using the earbuds in quiet surroundings. When using over-the-ear headphones, it couldn’t be detected.

Currently priced at £18.99 from Advanced MP3 Players, the E6 is an inexpensive personal amplifier. It might have a budget price but the E6 punches above its weight, counteracting the tinniness of digitally compressed sound with depth and feeling.

Most of testing was carried out with Sennheiser CX-300 earbuds, Sennheiser eH1430 headphones and a Sansa e250 mp3 player.

Thanks to Advanced MP3 Players for the loan of the E6.