ALO Audio Rx Mk2 Portable Headphone Amplifier (Playback 43)

Rich, Powerful, Clear Sound

But play the same track, from the same iPod, but with the Rx Mk2 in play and literally everything about the sound immediately gets better. Suddenly, sonic details (which sound at least as clear through the ALO as they did through the iPod) become better balanced and properly portioned, so that overtones and harmonics become sweetly integrated with the fundamentals of the notes that produced them, rather than sticking out like sore thumbs as they do through the iPod. Moreover, the timbre of Jones’ guitar sounds much more natural and truthful (not to mention sweeter) through the ALO, losing the disjointed, edgy quality it sometimes exhibits through the iPod alone. Finally, reverberations within the recording space, which are beautifully captured on this track, become much easier to hear and more believable through the ALO. Taken individually, these sonic benefits might seem small on paper (er, pixels), but taken together they add up to the kind of truly substantial, night/day improvements that, once heard and appreciated, become addictive and oh-so-difficult to forego.

But the ALO’s benefits don’t end there, because one of its greatest strengths involves an uncanny ability to capture the power, depth, and natural warmth of well-recorded music—especially as pertains to mid- and low-bass performance. Significantly, this is also an are where some of the iPod’s inherent weaknesses are most apparently, meaning that the iPod’s bass can at times seem weak and ill defined, as if some of the life and potency of bass guitars, kick drums and the like has simply gotten lost in translation. As a result, iPods can make music that has (or at least should have) a solid bass foundation sound as if it has been “cut off at the knees,” so to speak—sometimes to the point of taking on an unnaturally midrange-forward character that simply isn’t right. But with the ALO Rx Mk2 in play, the low-frequency foundations or underpinnings of good recordings are wonderfully brought back to life, with appropriate (never overblown) power, clarity, and depth.

To appreciate my point, here, try listening to a later track form Jones’ Roadhouses & Automobiles, called “Don’t Need Your Religion”. The track opens with bassist Grischka Zepf laying down a simple but forceful and downright subterranean electric bass line—a line that becomes even more urgent and syncopated as the song unfolds, so that it becomes, in a very real sense, the locomotive-like pulse that drives the song forward. Or at least that is what is supposed to happen, and actually does happen with ALO amp in the system. But take the ALO out of the system, listen through the iPod alone, and notice what happens. In an instant, the depth, potency, and vigor of Zepf’s bass line drains away, leaving the song bereft of energy and drive. The same thing also happens with the song’s vigorous percussion lines. With the ALO amp in play, percussion instruments have drive, snap, and tremendous dynamic life. With the ALO removed, the drums suddenly sound listless, watered-down, and lifeless.

Multiply results like these across many different types of music as played through many different models of earphones and headphones, and you can begin to see just how valuable the sonic contributions of the ALO Rx Mk2 really are. No, this amplifier isn’t cheap, but yes, it is worth the money—or at least it is if you want hear your favorite music reproduced with the clarity, tonal richness, and dynamic life that it deserves to have.

Bottom Line

The ALO Audio Rx Mk2 portable headphone amplifier has been a wonderful, reference tool that has served Playback (and its readers) well in countless evaluations of high-performance earphones and custom-fit in-ear monitors. The Rx Mk2 is one of those rare components that can make all types of music and most if not all types of earphones/headphones sound their best. Though not inexpensive, the RX Mk2 does it all, offering clarity, detail, tonal purity and richness, and faithfully conveying the life and natural warmth of the music.

Associated Equipment

Sources: Various generations of iPod Classics and iPhone 3G loaded with lossless audio data files ripped from CDs (and hybrid SACD’s)
Cables: ALO Audio 18awg OCC Triple Pipe Cryo iPod/iPhone Cable, Moon Audio Silver Dragon LOD Cable
Universal-Fit Earphones: (not an exhaustive list) Klipsch Image X10i, Phonak Audeo PFE 122, HiFiMAN RE-262, Monster Cable Turbine Pro Copper Edition, Monster Miles Davis Tribute Model, Sennheiser IE8, Shure SE535, Westone TrueFit-Series 4
Custom-Fit In-Ear Monitors: JH Audio JH16 PRO, Sensaphonics 2MAX, Ultimate Ears In-Ear Reference Monitors, Westone Elite-Series ES5