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Test N°.1
Source: iPod Classic 160GB, AIFF files
Interface: Sieben Technology dock
Cables: Zu Pivot 2xRCA-to-mini and
ALO Audio mini-to-6.3mm extension
Amps: Pico vs. Rx
Headphones: ALO rewired Sennheiser HD800s,
ALO rewired AKG K702, HifiMan HE-5LE |
Pico gain: In hi-gain mode and for stout levels, the volume control sat at 3:30 for the Sennheiser and AKG, at 5:00 for the HifiMan. While I didn't expect the planars to come alive, they very much did. True headbangers would redline available gain with the planars, the majority would be fine on the majority of recordings.
Rx gain: Lower than the Pico and for slightly lower levels over the HE-5LE, bang-on maxed out. The Pico has the beefier output stage. In terms of drive—control, no distortion—both are applicable for even the magnetostats. In terms of gain, the Rx is borderline for them, the Pico still inside the window.
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Sound: HifiMan HE-5LE, Pico vs. Rx - The miracle of modern op amp technology coupled to the low impedance and high current delivery of compact batteries makes a mockery of bystander preconceptions that would invoke shrinkage of scale and impact commensurate with physical size. I had the matching 2wpc HifiMan EF-5 amp, my gargantuan 8wpc Woo Audio Model 5 and the Burson and Corda amps as reference. I knew exactly what the nearly purely resistive planars were ultimately capable of. Neither of the portables condemned them to sound tonally or dynamically starved. It boggled the mind but was plainly demonstrable. On 'high-resolution' 16/44.1 material like Andreas Vollenweider's Air, density of tone and visceral energy would have made most speaker systems blush. These are strong points for this new Chinese statement headphone and the pocket amps played to them fine.
The Pico threw a laterally more expansive airier soundstage, the Rx was more compact. The Pico's contrast ratio or edge definition was higher, making the Rx slightly softer and more laid back by comparison. While head staging doesn't really move forward or backward relative to the listener, the effect here was related to sitting a few rows farther back - not in terms of actual distance but nearfield sharpness and dynamic stretch.
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On bouncy fare like Angélique Kidjo's where funky Latin bass lines support the overall African party vibe, the amps were very closely matched - even and really extended, trading the visceral impact of regular loudspeakers for superior linearity. For fascinating modulations, I like Enrique Morente's strangely tweaked voice and Vicente Amigo's Paseo de Gracia features him on the lengthy "Autorretrato". Here the HE-5LE's overall smoothness and relative lack of air versus the HD800 had me reach for the latter to comment on fine harmonic retrieval.
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HD800, Pico vs. Rx: Sennheiser's flagship is the most powerful microscope in my present headphone collection and in matters of raw resolution, in a different class than the warmer cozier planars. In stock form, the HD800's treble is bright and the bass somewhat recessed but a premium aftermarket cord addresses this imbalance successfully. The same "Autorretrato" track now showed significantly more aeration in Morente's harmonic shifts and hoarse inflections. Recorded ambiance—what I call audible space—was more acute. With the Sennheiser's opening up the top, it now became apparent how the Pico was a bit more potent in the lower midrange. This shifted Morente's vocals deeper in the diaphragm for greater weightiness. The Rx tracked the harmonics just as well but being a tad more 'upward' balanced, seemed throatier.
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For a female counterpart, I scrolled the maxed-out iPod to Azeri Kızı Günel performing that most famous of Azerbaijani songs, "Ayrılık" from her album Adi Yok. Featuring classic-style sweeping violins and octave-doubled clarinets with accordion, hand drums augmented by bass to appease modernity, this version is a lush production crowned by her powerful and sinuous pipes contrasted with male chorus interludes. Mastering quality isn't on par with Vollenweider so the sound is generally edgier and more compressed. The Pico laid this bare a bit more than the Rx which I'd call slightly more forgiving. That said, neither amp per se leans into the bright, lean forward camp by any stretch. As high-feedback devices, purists view op amps with disdain. These micro-power pocket amps are quite a slap in their faces. |
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AKG K-702, Pico vs. Rx: The Austrians cans over the Rx were brighter and leaner. Günel's Azeri ethno pop now veered too far into compromised pop production. Curiously, the Pico didn't to quite the same extent. In my collection, I find the AKGs the most dead neutral and as such, the potentially flattest and most boring. This assessment rather transforms with a beefy class A amp like the Burson. While neither pocket amp had apparent drive issues with the K-702s, this was the one headphone I'd not recommend for them if you listen to a lot of Pop (which could go hand in hand with portable devices). Things became too steely too often. You might point at the iPod's output stage but the fact remains, portable amps are designed for portable sources. As such, snobbish idealism must cede to reality.
For an inverse reality check, I docked the iPod in the Peachtree Audio iDecco. The latter would handle D/A conversion and drive the Pico's input stage from its fixed line-out - deluxe in this context, decidedly stationary and as such, most unlikely. This scheme naturally overturned all previous gain considerations. Volume settings now set back time by three hours, with the Pico at exactly 12:00. Simultaneously, treble detail built out considerably. The iDecco's Sabre DAC is more insightful than the iPod's own converter. Despite this, the earlier steeliness was tamed and the K-702s became perfectly palatable. In fairness, source output voltage (and perhaps impedance) as well as general source quality are significant determinants in how elevated this type of portable amp will perform. While still on the iDecco, comparing its own 6.3mm output to the Pico seemed predestined. The latter's color palette was more intense and saturated, the overall presentation grippier, more tensioned and direct. Fed from identical signal, the Pico was superior.
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Test N°.2
Source: iMac 1TB, iPod, identical AIFF files
Cables: Generic mini-to-standard USB cable
ALO Audio mini-to-6.3mm extension
Amp: Pico
Headphones: ALO rewired Sennheiser HD800 |
As a portable device, the Pico's USB DAC might seem curious. That's why it's optional. What USB source would one plug into? Nothing walking the street but travelers might find themselves stranded in a hotel room or airport, laptop charged but nothing to do. For a first read on the Pico's DAC feature, I had used it as a miniature preamp in my review of the Joey Roth ceramic speakers. There it inserted between my MacBook Pro and Joey's T-amp. |
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It had blown the equivalent Calyx Kong USB headphone amp positively into the weeds and was clearly made of sterner stouter stuff. Not having a $149 HRT Streamer + on hand, I now had to isolate the Pico's converter quality vis-à-vis my iPod. The latter's library is sync'd from the iMac. Comparing iPod to iMac, the difference in the data streams would be the D/A conversion - the iPod's own vs. the Pico's. Because the Pico runs no physical input switch, one must disconnect the 1/4" link to pass USB signal.
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While on "Ayrılık", Jazz pianist Aziza Mustafa Zadeh too does a lovely reading on her Shamans album. And hers is well-recorded. Switching between converters while following her self-accompanied vocalizing showed immediately that the Pico thoroughly bested the iPod. Upper midrange and treble in particular were rather more informative and developed while the overall level of visibility or directness increased noticeably across the board. The delta of difference was vastly more pronounced than the earlier difference between amps. Justin Wilson didn't boast emptily when he called his USB DAC a cut above the usual in this sector. Returning to commercial Pop and the AKG K-702s merely reiterated the above proviso on source quality.
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Piped through the Pico's own DAC, even overcooked radio Baghdad fare from the likes of Amr Diab, Fadl Shaker, Ghazi Abdel Baki, Ilham Ad Madfai and Natasha Atlas (I enjoy Arab pop in the car and during workouts) didn't cross into questionable disco turf. Considering how compact and affordable the DAC-fitted Pico is, the extent to which it embodies 'source is king' becomes impressive.
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Where the Pico misses is form factor. As a dedicated portable amp, the iPod is its most likely source. Now the Pico's foot print becomes cumbersome relative to getting strapped to an iPod. Consider how the Rx piggybacks for the perfect flat-pack sandwich. I don't see an elegant way to do this with the Pico.
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From that perspective, the Pico + DAC matchbox seems quite the ultimate miniature desktop headphone solution for PC audio sources. While battery power becomes less meaningful in permanent installations, it'll be a life saver for the business traveler, the iPad surfer in the coffee house and writers who sit on a park bench or in a bar pounding the keys whilst running tunes.
Versus my 'big-boy' stuff—Burson, Corda, KingRex, Trafomatic, Woo, Yamamoto—the main difference with the Sennheisers and Pico was scale. There's a popular maxim that big amps sound bigger. It isn't always true but here was to some extent as it related to substance and dynamics. Particularly with the mondo Woo and to a smaller degree with the Trafomatic, the valve amps handled tone differently and in the expected ways. My favorite headfi rig at the moment is the Woo Model 5 with Emission Labs 5U4Gs, Synergy 6SN7s and EML 300B XLS or Shuguang Black Treasures driving the Sennheisers and being fed from the Weiss DAC2. The sense of grandeur and intensity that rig conveys goes beyond what such pocket amps can do. That's to be expected and no slight. What's important is that on its own merit, the Pico doesn't let on that even better is possible.
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A functional nicety is the rotary pot with its instant visual confirmation of where it sits. Add rainbow color options, a truly snazzy jewelry finish and American one-at-a-time build from a true cottage industry man. The Lilliputian Headamp Pico becomes a true find in the performance lifestyle sector. Who then really cares that Justin's website is marginal? Clearly the man stays busy building amplifiers. That's what you're paying for. That's what ultimately counts. Herr Justin does need to improve his communication skills. As it stands, feedback, general Pico intel and mutual hand holding whenever Justin drops the ball on emails all occur on a headfi forum thread which his site lazily links to. The Pico thread there extends already over 233 pages. That shows how the Pico remains popular. It also assures one and all that no matter what, Justin Wilson always comes through for his customers. I'm thus happy to recommend the Pico particularly with its optional USB DAC. That's a real sweat heart combo. |
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