With the continued growth of smartphones and the proliferation of hi-res portable music devices, the on-the-go headphone amp business is in full bloom. These portable amplifiers are appearing in all shapes and sizes, at price points ranging from affordable to astronomical.

But they’re worth checking out. If you have a decent pair of cans, you’ll appreciate the external power boost an amp provides. It provides a more vivid listening experience, and is yet another gadget to fiddle around with on airplanes and in cafes.

Peachtree Audio’s new Shift is a portable headphone amp, digital-to-analog converter (DAC), and also a battery pack you can use to charge your phone. It connects to a mobile device, a tablet, or a PC/Mac via a USB cable (there are both USB type A and B connectors). Then your cans or buds plug into the other end, where there’s a standard mini-jack. Lightning cables and USB cables are included.

For headphones that require more power than your computer or smartphone can produce, a headphone amp is a must. If your headphones work just fine right now, an amp punches up the sound, and is still a worthwhile investment. The Shift has an MSRP of $400, but you can find it for around $300 if you shop around. The device isn’t shipping yet, but pre-orders are available.

Anytime I get my hands on a portable audio device, I pay close attention to the build quality because I know it’s bound to get dropped, bumped, and knocked around. The Shift looks travel-ready, with a solid aluminum case flanked on top and bottom with leather and rubber pads. In the box is a sturdy leather case with extra room for a smartphone or portable player. At five inches by three inches, and weighing six ounces, it’s not too difficult to fit it into your pocket.

The four buttons are somewhat hard to read, but there are only minor adjustments you need to make (changing the source, flipping the power supply, adjusting the impedance) from time to time, so no biggie. LED indicators tip you off on the 4100mAh built-in battery level—charge time is about four hours, and run time about eight hours. The battery is also replaceable.

What Does the DAC Do?

Audio files are stored in a variety of sample rates and digital compression formats, and all of these need to be converted into an analog electrical signal before they can be sent to your headphones or speakers. This is where the DAC comes in. Most headphone amps include a digital-to-analog converter chip in the signal chain—the idea being that a dedicated, high-quality DAC is better at converting music than the cheap DAC in your phone. The best of them are tuned by expert audio engineers, and there are subtle differences in how each design transforms digital audio to acoustic signals.

Peachtree, a company whose first digital music amplifiers arrived at the dawn of the smartphone era, has made the right decisions here. The ES9010K2M chip (.pdf details) supports sample rates of up to 32-bit/384kHz, plus DSD64 and 128. Translation: You can throw just about any digital source through it.

After you get past the initial impressions of a more spacious, vivid sound, the character of the DAC and amp starts to soak in. The Shift certainly brings out more detail and clarity in the music, but it also creates a soundstage that works well across music styles, and holds up over longer listening sessions. Likewise, the boost in the bass response is impressive, but without going overboard, so it never strays into the muddy or flabby territory that some amps and headphones do.

Take “Sugah Daddy,” a funky-jazzy track on D’Angelo’s Black Messiah. The horns and guitar jump out of the cans, big and bright (without being shrill), and the complex mix of rhythms and vocal elements bounce around in a nicely balanced chaos. Now something louder, grungier and fuzzier, Ty Segall’s “The Singer.” This is the type of song that can turn into a sloppy, muddy mess in the wrong set of headphones. Here, though, the amp does a fine job of balancing the onslaught of electric guitars that jump in and out of the mix, and even with a thick layer of vocals on top, the overall sound is still impressive—or at least as good as one might expect when you’re caught in Segall’s sonic mayhem.

I’ve never owned or reviewed any Peachtree Audio gear before, so I didn’t have much context or expectations for the Shift amp. The company has my attention now. It certainly ranks among the most listenable and vivid headphone amps I’ve heard, and the build quality and features hit the mark, too. Of course, $400 is a pretty penny to spend on a portable amp, so it shouldn’t have any limitations or drawbacks at that price point. Paired with a good set of cans, like the Master & Dynamic MH40 used in this review, the Shift provides an immersive audio experience that makes you want to sit back, relax and dive into some music.