Alpha Design Labs by Furutech • Stride Headphone Amplifier

by John Crossett | June 26, 2012


The portable audio market has become one of hottest, fastest-growing areas in consumer electronics. It’s no longer uncommon to see the cord for earbuds or headphones dangling from the ears of people walking down the street, sitting on park benches, or riding bicycles, or to see people playing music or movies via their computers (or tablets) in planes, trains or automobiles. We can thank the late Steve Jobs for a good portion of this phenomenon. The iPod and iPhone (and their various decedents and clones) have made taking our music with us so much easier, while computer-storage makers have produced larger-capacity and physically smaller hard drives that give us the space to store more audio and video on our computers. However, audio in the computer world generally seems to have far more to do with quantity than quality; you only need to look as far as MP3 to get that message loud and clear.

Fortunately, not everyone wants dumbed-down audio. Together with the advent of the iPod and the use of computers to store music has come a sub-industry catering to those music lovers who want something better from the audio files stored on their iPods and computers than the MP3/giveaway-earbud default. So, just as Wadia extracted a digital signal from the iPod with its i170, allowing listeners to bypass the limitations of the onboard DAC, we now have audio companies designing small, portable headphone amps to take the analog output from a portable audio device or computer and make it suitable for use with full-sized or high-quality portable headphones, finally allowing us to toss the freebie earbuds. Japanese company Furutech, through its Alpha Design Labs (ADL) division, has recently joined the fray with the Stride headphone amplifier, and if the specs hold true through the listening tests, then it might be just what the audiophile is looking for to fill this niche in his personal listening time.

The Stride is a lightweight black-anodized aluminum amplifier (it can also be purchased in a neat-looking carbon-fiber-bodied version called the Cruise for roughly $150 more). It weighs in at a mere seven ounces and fits easily in hand. It’s attractively designed with a curving, contoured shape that will undoubtedly help it stand out in a world populated with small black boxes. On the front panel are a 3.5mm input jack, a 3.5mm headphone jack, a rotating volume wheel, and a blue LED to show that the unit is switched on. Around back is the on/off switch and a mini USB jack that allows for attachment to either the wall-wart recharger or your computer, and a red LED to show that the unit is charging. That’s it. The Stride offers only those bare necessities required for its operation and nothing more.

It’s refreshing to see a spec sheet that gives a clear view of how a portable device will work with a multitude of different headphones. The Stride's power is offered at varying degrees of load: 78mW at 12 ohms, 94mW at 16 ohms, 110mW at 32 ohms, 98.6mW at 56 ohms, 23mW at 300 ohms, and 16mW at 600 ohms. I can attest to the robustness of its output -- it drove all of my headphones and earphones to levels best left unheard. The DAC chip used is a Wolfson WM8716 24-bit/192kHz model, and the USB chip is the Tenor TE7022L, a 24-bit/96kHz part. The Stride takes approximately five hours to charge and offers up to 80 hours of playback time when fully charged. I didn’t time it, but I can say that in all of the time I used the Stride I only recharged it once -- and then only because I thought I should, not because it ran out of juice. Oh, and the Stride has an internal, rechargeable Li-Ion type 14650 battery, so no wasting money on alkaline batteries. The Stride comes with a one-year warranty.

I asked Jonathan Scull, who handles ADL by Furutech's PR duties, about the out-of-the-ordinary physical design of the Stride and his answer was, "Furutech’s Pure Transmission Anti-Resonance and Shielding Technology is used throughout Alpha Design Labs products. The Stride’s carefully designed extruded-aluminum body and internal construction keep interference and resonance at a minimum, so the music remains unperturbed and undisturbed." My take on this is that the Stride was designed to be both a shield against outside elements affecting the signal path as well as eye candy for other portable-music aficionados.

Stepping out

Vivid: that's the word that sprang to mind after I fired up the Stride for an initial listen. Music seemed to jump out of the headphones. Each instrument or singer was full-bodied and three-dimensional, a part of the whole while never losing the clarity and individuality so familiar from the real thing. I use "vivid" in the same way that "Technicolor" was used by Hollywood to describe the process that made movie colors seem more alive, more intense. The Stride gave me that same feeling whenever I listened to it. Everything I played through it, from MP3 to my Apple Lossless files on my iPod Classic/Touch to the high-res files on my computer seemed to take a step closer to the recording itself, making me want to spend extra time listening. Fortunately, the Stride never slipped across the line between "vivid" and "brash" -- the latter pales soon after purchase, while "vivid" just leaves you wanting to do more listening.

The Stride’s sound was clean, clear, detailed and alive, and it also demonstrated a sense of both space and the overall acoustic (provided it was on the recording, of course), the music sounding real in important ways. Its ability to place each instrument and vocalist within its own individual space was among the best I’d heard from a portable headphone amp. I have come to love the song "Saving Grace" by the artist Everlast (from Love, War, And The Ghost Of Whitey Ford [The Ring Project TRP901262]). The original CD is superb, and my Apple Lossless rip to my iPod is just as explosive. It was so easy to hear the twin acoustic guitars, their strings being plucked and strummed, each surrounded by its own cushion of air. I could hear the same thing with the balance of the band, the drums, electric guitar and bass. And Everlast’s vocals were right there, front and center and fully fleshed out, but without a sense of being thrust at me. I could hear the rough, whiskey-soaked sound of his voice, reproduced via the Stride with just the right amount of texture. Background vocals were also clearly recorded, with each individual singer set back in the mix but still clearly rendered in the space he or she occupied.

The Everlast song also demonstrated the power of the Stride’s bass. I’ve listened to this song though my big system, and the bass and kick drum slammed me in the gut. Well, the Stride gave that same feeling, but in the head. And it wasn’t just that the bass went deep -- though it did that in spades -- but how detailed it was. On the Everlast song I could easily make out the differences between the hammer hitting the skin of the kick drum and the pluck and throb of the bass guitar, even with notes of similar frequency. Each had its own sonic signature as well as its own cushion of space. When I switched to Marcus Miller’s version of Billy Cobham’s "Red Baron" from the album M2 [Telarc 83534], the Stride provided that signature electronic purr to Miller’s electric bass, making me again feel closer to the recording. That a small, portable headphone amp just slightly larger than that of a pack of cigarettes could impart this kind of low-end hump, and at such a modest price, was certainly ear-catching.

Something else the Everlast song demonstrated was just how dynamic the Stride could be. Each pluck of a guitar string had a solid initial transient, emerging from nothingness to full sonic splendor in a heartbeat -- and then fading back to black only to be replaced by the next note. No matter what I listened to, from jazz to rock to classical, the Stride projected the full dynamic swing of any well-recorded music.

Edge definition of instruments and vocals aided this with their effortless separation. There was little blurring to the individual sounds, which kept them vividly (there’s that word again) sharp and real. The Stride made it very easy to follow whichever instrument or vocal I chose to; yet, while doing so, I never lost the sense of each part belonging to the whole. Again, this blending of parts to create the whole is seriously reminiscent of live music.

While the Stride had power to spare, it didn’t shortchange tone and timbre. Rips of my Mozart CDs allowed me to hear just how well it handled the delicacy of strings. I love the "Gran Partita Serenade" [Philips Classics 412-726-2], especially the way Mozart blended the strings with the woodwinds and horns to create a delicate yet powerful piece. Using the Stride to listen to the version by Sir Neville Marriner and the Academy of St. Martin In The Fields allowed me to feel in the presence of the orchestra. The strings were buttery smooth but with just the right sense of the bow’s rosiny scrape. The woodwinds had that same sense of air moving past and exciting the reed and body of the instrument. Finally, the horns were reproduced with the requisite metallic blat. Yet, while making each section -- and each musician -- distinct in his playing, the Stride again never lost its focus on orchestra's whole. The piece was complete with a sense of passion and humor, just as Mozart wrote it. Plus, all this was laid out on a soundstage that stretched from ear to ear. Yes, the Stride did the soundstage thing with aplomb. Many headphones and headphone amps have a hard time reproducing the sense of space that gives what we hear from our speaker-based stereos its true feeling of reality. Some makers compensate for this with circuitry, like crossfeed, which mimics that sound. The Stride didn't need those additions, as it managed to do the same thing without any special bells or whistles.

Listening to my high-res files was as simple as attaching the Stride to my computer via the supplied USB-to-mini USB cable and clicking play in my computer program. There were no switches or settings on either the Stride or my computer to ensure that I had the correct high-res output, but I could immediately tell the difference. Instruments were more fleshed out, more three-dimensional. That cushion of air around them was even more alive with the sounds of the acoustic. Vocals were also more full and rounded. It was easier to hear how the singers formed each word and how their individual vocal nuances contributed to the character of their voices.

As a final bonus, the Stride never showed any sense of stress, no matter which of my headphones I used. Both of my AKGs -- the '701s and the '601s -- were a perfect match, but the much more demanding Beyerdynamic DT770s, with their 250-ohm load, were handled equally well, as were Shure E540 in-ear monitors. No matter the load, the Stride just pumped out music with no sense of stress. I found this aspect particularly appealing, as I never had to give a moment’s thought to which headphones I wanted to use; I just picked the right headphone for the moment, knowing that the Stride wouldn’t care.

Keeping pace

I stacked the ADL Stride up against both my HeadRoom Total BitHead and Portable Micro Amp with DAC. The Total BitHead ($149), while having much the same capabilities built into it, sounded very different from the Stride. It had a smoother overall presentation, with much less definition, edge sharpness and space. It also had nowhere near the low-end heft of the Stride. I guess four AAA batteries can’t compare to the rechargeable internal battery of the Stride when it comes to low-end power. The Stride was, to use that word again, much more vivid in its re-creation of the music. The only aspect where I preferred the Total BitHead to the Stride was ergonomic -- the Total BitHead was better designed for use on the go, with three spots on the back for the included Velcro tabs that allow my iPod to attach directly to the BitHead’s case. Both the Stride and the Total BitHead have the ability to run from a computer’s USB connection, thus saving battery time. But the Stride’s internal rechargeable battery lasts far, far longer, giving you loads more listening time between recharges and thus eliminating the need and cost of replacing the AAA batteries needed for the Total BitHead.

Stacking the Stride up against the more expensive HeadRoom Portable Micro Amp with DAC ($549) using the Everlast song "Saving Grace" provided more of a sonic contest. While both reproduced a credible soundscape, the HeadRoom amp was smoother, focusing more on the wholeness of the presentation. The Stride was again the more lucid of the two, with a sound that revealed the individuals as well as the whole group. The bass was very close, due in no small part to the internal rechargeable batteries in each. But the low-end nod would still have to go to the Stride. It had a bit more definition and went a bit lower with more authority than the HeadRoom amp.

Both amps are similar in use -- that is, both take a line-in analog or USB digital signal, and both have internal DACs that decode 24-bit/96kHz signals. The HeadRoom amp can’t be powered from its USB jack, however, but it does offer both a crossfeed circuit and a three-position switch to control gain. It also has an optical digital input and a volume-controlled line output. But it is also larger and heavier -- a consideration if true portability is a prime requirement, while the lighter, smaller Stride can easily fit almost unnoticed in your pocket.

So it’s up to you: the extra features and added weight of the Portable Micro Amp with DAC or the ADL Stride’s sonics, long battery life and more transportable form.

Big shoes

If you’re simply looking for a small, powerful headphone amp with enough features to allow you to use it in multiple portable/computer situations, you want it to be not only sonically but visually striking and you don’t want to pay too much for extra options you may or may not use, then the ADL Stride should be on your short list. I know, I know -- the visual part shouldn’t be much of a consideration, but come on, who among us doesn’t like attractive gear, especially if we carry it around in public? And with the Stride, you get all the goods -- foremost among them impressive sonics and a noticeable appearance -- all rolled into a single small package. One listen and you may well find that the vividness that is the Stride’s strongest sonic trait tips the scales in its favor. I know it made quite an impression on me, and I will miss the Stride greatly after it goes back.

Price: $399.
Warranty: One year parts and labor.

HDL Distributing
(888) 204-5768

Furutech Co., Ltd.
3F 7-11-1 Nishi-Gotanda, Shinagawa-ku
Tokyo 141-0031 Japan
+81-(0)3-5437-8470 (USA) (International)

Associated Equipment

Digital: Apple iPod Classic, Oppo DV-981HD universal player, Toshiba Satellite laptop.

Headphones: AKG K-601 and K-701, Beyerdynamic DT770, Shure E540.

Headphone amps: HeadRoom Portable Micro with DAC and Total BitHead.

Interconnects: Analysis Plus Solo Crystal Oval.

Power conditioner: Blue Circle BC6000.

Power cords: Harmonic Technologies Pro AC-11, Analysis Plus Power Oval 10.