Top 4th of July Sales Best 4K Projectors 7 Early Prime Day Deals Wi-Fi Range Extenders My Favorite Summer Gadgets Cheap Car Insurance Target's 4th of July Sale Best Running Earbuds, Headphones

ADL X1: This gizmo will pump up the sound of your iPhone

The X1 is a combination digital converter and headphone amplifier, and the Audiophiliac thinks it will make your iPhone, iPad, or iPod sound better than ever!

The ADL X1.

Over the past year or so we've seen a new product category emerge: the portable digital converter/headphone amplifier. Of course, no one "needs" such a device -- phones and iPods already have converters and amps built-in -- and sound perfectly fine with average headphones. The sound is good enough, but your phone's converter and amp share space and battery power with the phone's electronics. A separate converter and amp, about the size of a phone, has only one mission: improved sound quality. So if you upgraded to a high-end in-ear headphone, like the $399 Logitech UE 900, or a full-size Hifiman HE-400, you'll be in a position to hear what the ADL X1 converter/amp brings to the party. It will make your headphones sound like better headphones.

The ADL X1 handles 16-bit/48kHz digital audio via USB cable when connected to an iPod, iPhone and iPad, or 24-bit/192-kHz audio via USB with Macs or PCs (the X1 doesn't work with Androids or other phones). The small LEDs on the ADL X1's case indicate the digital sample rate -- 44.1, 48, 88.2, 96, 176.4, or 192kHz -- of the music being played. Connectivity options are good, in addition to the 3.5mm headphone jack, you get a 3.5mm analog input, iDevice USB input, USB mini B, and a 3.5mm optical digital audio output. The ADL X1 measures a trim 2.6x4.6x0.7 inches and weighs 5.2 ounces. The case is metal and plastic, and the X1 has a volume control knob, not up/down buttons, so it's easy to quickly set exactly the volume you want. The ADL X1 uses a 3.7 volt/2,600mAh lithium ion rechargeable battery. The ADL X1 comes with a USB-to-30-pin Apple cable -- that's how I hooked it up to my iPod Classic -- and starting with units shipped after July 8, an Apple Lightning cable will be included.

Setup was a simple plug-and-play routine -- and I noted sound improvements in clarity, bass power, definition, and soundstage spaciousness -- compared with listening to the iPod Classic solo. The Raconteurs' "Broken Boy Soldiers" packed a bigger wallop over the ADL X1; it makes headphones sound like better headphones. Of course, it doesn't make sense to team the ADL X1 with a set of cheap or even moderately priced headphones -- definitely buy better ones first, but if you've already invested in a high quality headphone, the ADL X1 can take the sound to the next level. I listened with Cardas EM5813, Logitech UE 900, and Jerry Harvey JH 13 in-ear headphones, and Hifiman HE-400 full-size headphones. All were improved by the X1, but it really clicked with the HE-400. The iPod Classic on its own could not come close to matching the ADL X1's dynamic kicks.

When I compared the ADL X1 to the $598 V-Moda Vamp Verzadigital converter/headphone amps they sounded similar, but the ADL X1 was a tad softer and sweeter sounding with my Jerry Harvey JH 13 in-ear headphones. The ADL X1 pulled way ahead of the Vamp Verza with the Hifiman HE-400. That said, the Vamp Verza's big advantage is that it works with iDevices and Android phones; the ADL X1 is just for iDevices (or Macs or PCs).

I heard a small amount of noise/hiss from the ADL X1's amplifier over my headphones, which was also true with the ALO and V-Moda Vamp Verza amps I've tested. I didn't find the noise all that intrusive, but other listeners might be put off by the noise.

The ADL X1 is available online for $479.