Tension Labs EAP03 Audio Processor

The Tension Labs EAP03 ($179) is a personal headphone amplifier intended for hi-fidelity audio enthusiasts looking to get the best performance from high-end in-ear headphones.

Design
Measuring 3.25 inches by 2 inches by 0.5 inch, the Tension Labs EAP03 has the look and feel of a knockoff iPod Mini constructed by the lowest bidder. Despite its metallic look, the Tension Labs EAP03 is plastic from head to toe, with a subpar build quality that doesn't match its lofty price tag.

On the front of the Tension Labs EAP03 you'll find a 1.5-inch monochrome LCD that displays volume and setting information in legible, yet crude, lettering. Below the display you'll find a built-in microphone and two clear acrylic buttons for enabling the Tension Labs EAP03's audio processing, or external noise monitoring features. The Tension Labs EAP03's doesn't include a button hold switch, however, making it all too easy for the gadget to turn on or off accidentally.

On the left edge of the Tension Labs EAP03 you'll find a single spring-loaded scroll wheel for navigating and adjusting the Tension Labs EAP03's settings. The bottom of the EAP03 includes a USB charging port and two 3.5mm stereo jacks for routing audio in and out.

Beyond the Tension Labs EAP03's aforementioned cosmetic shortcomings, there's a larger design issue to deal with here, namely: size. For what amounts to an incremental improvement in audio quality, it's cumbersome to carry around a device as large as the EAP03 along with your MP3 player. Granted, there is a small, but devoted, faction of audio enthusiasts roaming around with much bulkier headphone amplifiers, such as the HeadRoom Bithead--but that doesn't make the proposition any less ridiculous.

Features
As the two buttons on the front would indicate, the Tension Labs EAP03 has two basic functions. First and foremost, the Tension Labs EAP03 is an earphone amplifier, meant to optimize your MP3 player's performance with high-end in-ear headphones such as the Shure SE 530, or Ultimate Ears Super.fi 5. To make this audio magic happen, the Tension Labs EAP03 employs dual 24-bit Sigma Delta audio codecs on a 48-bit processor packed with detailed EQ, amplification, and spatialization settings.

Just how many gadgets are we expected to reasonably cram in our pockets, exactly? The EAP03's bulky plastic design makes us wonder if squeezing extra fidelity from our earphones is worth the effort.