Otherwise, your mileage may vary. I used a set of Klipsch Custom 2 IEMs and a set of Denon AHC-551s, and got decent results from both. With the Custom 2s I definitely experienced a richer sound, more definition and a wider soundstage than I get with my 2nd gen iPod touch straight from the headphone output, with particular gains for more electronic music (Bat for Lashes’ Pearl’s Dream, Massive Attack’s Inertia Creeps, Justice’s floor-filling DVNO) and rock (Pearl Jam, Mastodon, Audioslave). It also helps that you can use the EQ to patch the weak points of your IEMs – in the case of the Custom 2s, a less than crystalline high-end. To my surprise, the EAP03 wasn’t thoroughly outclassed by the iBasso D2, either. Sure, the D2 offers a crisper low-end and a bit more definition overall, but the EAP03 provides equivalent power and presence.
With the Denon ‘phones there was less to choose between the two portable amps; in both cases, you get more punch and a greater sense of space than you would with the standard headphone output, and a far better sound than you’d expect from such relatively cheap earphones. Just be aware that the 3DX option gives you markedly different results depending on both the earphones you use and the type of music you play through them. I’ve had everything from no difference to more realistic sound to a total mess during testing, which led me to switch the option off after a while.
Speaking to Gordon, who has also been trying out the EAP03, it appears you can also expect great things from the Etymotic ER4s and HF2s, with the EAP03 providing a more exciting, powerful sound from the already clean, well-balanced IEMs. He also rates the EAP03’s efforts with the Shure SE310s, citing enhancements to overall fidelity.
As you might expect, the D2 does more for demanding, over-the-ear headphones, pumping a richer, more energetic sound through the DT770 Pros and a pair of Grado SR125is than the EAP03, but then that’s not really Tension Labs target.
However this – and the price tag – means that if you’re in the market for a headphone amp, the choice is a difficult one. Those looking for a decent boost in performance from low to mid-range earphones and IEMs should still look at FiiO’s bargain-tastic offerings first, and the iBasso is still the most versatile headphone amp around, providing great portable sound, better support for full-sized headphones plus an external DAC, along with better battery life than the EAP03. If, however, you’ve invested £100 or more in IEMs and you’re prepared to invest another £160, then you’ll be pleased with what you get from the EAP03. It’s a good product, and with a little more work could be a great one. What’s more, it might just help save your hearing for many years to come.
The EAP03 is targeted at a niche market, and so it’s not the most versatile of headphone amps, but if you want optimal sound from your IEMs and access to a range of useful features, then the Tension Labs unit is worth the sizable outlay.
Score in detail
Sound Quality 8