Note: With the FiiO Q1 arriving at our delivery hub today I thought it best to relive the simple joys brought by its older cousin, the E11K. Though officially the successor to the E07K, I personally think that the styling and amplification capabilities share more than enough to link the Q1 with the E11K. Reposted from our eBay store. When FiiO first made inroads into the high resolution market, you can arguably say it was because of the affordable quality of the E11. This sub £100 amp helped open the door for new audiophiles to realise the full potential of their music by making good sound better. FiiO could have rested, they could have thought the E11 project complete and moved on, leaving it to slowly become redundant as technology moved on. FiiO decided against this path and after this initial success, went back, enhanced and then produced the E11K; a unit that makes better sound exceptional. How? Well stick with this guide and we here at the AV Shop will explain the key differences between the two and what that can bring to your listening experience. [caption id="attachment_67" align="aligncenter" width="660"] The E11K proudly sitting on top of it's older sibling.[/caption]Most visibly, the plastic case found on the E11 has been wholly re-designed in black brushed aluminium. This is not solely an aesthetic choice as the aluminium helps to minimise electro-magnetic interference (that beeping you hear in your headphones when you’re about to receive a text). Equally the elliptical curves of the E11K allow the unit to house a 1400mA battery, giving you over 16 hours of life on one 4 hour charge. The E11K retains the gain switch (High and Low) to add that extra power for demanding headphones though it swaps a 2 stage EQ for an optional dedicated bass boost circuit. The E11K has a recommended headphone range of between 16~150 Ω though it has been known to power 300 Ω Sennheiser (like the HD 650). Of course, the further from the recommended range, the lesser the audible results so it is not advisable to use it specifically with 150+ Ω headphones. A common misconception about headphone amplifiers is that they are used exclusively to increase output, making the sound louder and powering high impedance sources. This is not the case; as mentioned in our ‘beginner’s guide to headphone amplifiers’, a separate, dedicated amplifier can refine and bolster the frequency range of your sound. Using one basically splits the workload so that the audio source doesn’t use more power (a precious commodity for any portable) than needed while the amp can use its individual power supply to focus on the job at hand. This access to extra power allows for a greater variety of amplifier chips and therefore far more scope for customization: no two makes of amplifier will sound the same. In the case of the E11K, FiiO have gone with a Texas Instruments OPA1642 as the voltage amplifier and an AD8397 as current amplifier. Together these chips help layer the sound, control the low frequencies while extending the highs and mids; making the music sound more urgent and real. [caption id="attachment_68" align="aligncenter" width="432"] Continuing the refinement as the A3[/caption]As to be expected (and especially in this post-Q1 world), FiiO didn't stop there and earlier this year chose the E11K to launch their re-branded amplifier series. From the E11K came the A3, an identical unit in a new silver shell. Now before you all go and complain that this isn't an update (because I agree, it's not), we should probably explain a little about FiiO's naming structure. The initial grouping of all amplifiers, whether dedicated or not, was made by the letter E followed by a mountain (in this case, Kilimanjaro). Now, all hybrid portable amplifier/DACs will begin with Q while all dedicated amplifiers will begin with A. The E11K becoming the A3 while the E07K is followed by the Q1. Like the X series before, each of these series will only use odd numbers with 5 (or 7) being the top range and 1 being entry level. After initial doubts, I think it's actually a far easier way of grouping FiiO increasingly specialised output. Especially considering we're in for 2 new ranges in K (for desktop amplifier/dock/DACs) and M (hyper budget DAP). I, personally, love my E11K and find it a cheap, simple and - frankly - cool way of enhancing my music. If you like music and especially if you love listening on the move with decent headphones; a headphone amplifier is a must. There is almost no convincing way in which to describe the audible benefits without trying it yourself but thankfully the E11K (or A3) provides an option at an amazing value. Try it for yourself today and see our range of FiiO products available at our AV Shop eBay store.