I have had the luxury of testing this product out, and I was EXTREMELY pleased with it. First off, WOW. That is one of the most unique ideas I have seen for a headphone amp. I have tested numerous different headphone amplifiers, some of them rigged up with a 9volt, and some of the more reputable amps like beyerdynamic, and Grado (which I read was using the same chip). I think it is extremely clever to take such a common item, that probably 90% of people would recognize, and transform it into such a beneficial accessory to the fastest growing market out there. I listened to headphones for years before I even knew that portable headphone amps exist. Since then, I have been transformed into a die hard fan. I don't think that many people even understand the benefit of a headphone amp. This took a pair of headphones that were harsh, with too much treble, into a perfectly balanced set that sounded 10 times their $$$$ value. Anyways, back to the review...

When I first got the amp, it was in the MOST basic of packaging. I have learned from experience: it's not the fancy box, or face on it, it's what it can actually do. So, I opened it, and sure enough, an Altoid container. The build on it is far more stable than I had anticipated. The volume knob has a nice, sturdy feel to it. The battery fits securely into its position, and all parts were fixed.

The amp has a protection mode that will not allow it to turn on unless there is something hooked up to it, which I thought was a great feature. When I opened it, I immediately went for the bass boost button. The headphones I was using were INCREDIBLY accurate for all the top end, but I wanted to hear the bass. BOY, did I hear the bass. Now I prefer it just amp'ed, and no bass boost. It's got a rich, warm sound to it. I actually prefer it over most of the entry level FiiO amps I have tried. The battery lasted over a month of constant usage, and I love showing it off. Everyone I have let use it has felt very similar to my evaluation.

Overall, I would rate this 5 stars and highly recommend it to anyone who is looking to really enhance the performance on their relatively low impedance headphones!