Qables iQube V1 Headphone Amp & iQube V2 Headphone Amp/DAC (Playback 38)

A Class D Powerhouse from Holland

Interestingly, the song features Jones supplying overdubbed backing vocals of his own, but with some supplementary contributions from other singers at specific points. The detail and definition levels of the iQube are sufficiently good that you can tell in an instant whether vocal harmonies are supplied by Jones, by the alternate singer, or—in some cases—both.

Similarly, the iQube nails the almost vocal growl and snarl of Maucksch’s fretless bass guitar, whose sound, I have found, is not necessarily easy to reproduce. Many amps have at least some trouble with this recording, because the lower register of Jones' voice overlaps with the range of the fretless bass, which can be a recipe for muddled low-end performance. But not so with the iQube; it makes child’s play of disentangling and delineating the overlapping voices, while convey the deep throb and weighty punch of the lowest bass guitar notes.

But to see what I meant by my comments to the effect that the treble region of the amp/DAC can at times sound slightly dry, put on the excerpt from the Paul Goodwin/Minnesota Orchestra/Minnesota Chorale performance of Tavener’s Icons of Eros as captured on the Reference Recordings 30th Anniversary Sampler. The piece is cleverly constructed so that it presents jaunty, almost dance-time sections as performed by strings and percussion, which alternate with much slower paced choral/string passages offered up with low percussion accents. The challenge, however, is that there are moments of silence between the alternating sections where you can hear the sounds of the previous passage slowly echo and then fade to silence within the highly reverberant recording space.

During these reverberation-filled moments of silence you get the opportunity to experience the iQube amp/DAC’s handling of low-level treble information as heard in isolation from the rest of the music. When this happens, I found that the echoes and reverberations, which can and should sound highly realistic through the best amp/DACs, tended to sound a slightly dry and artificial through the iQube V2—almost as if I were listening to sounds created by a good synthesizer rather the sound of live instruments in a natural recording space. As I noted above, however, some headphones make this quality of treble dryness more apparent than others, while some do not show it at all.

COMPETITIVE COMPARISONS

With an eye toward helping readers place the iQube V1 and V2 versus likely competitors I will make two comparisons, one showing the iQube V1 amp vs. the new ALO Audio Rx MkII headphone amp, and the other showing the iQube V2 vs. the CEntrance DAC Port amp/USB DAC.

iQube V1 vs. ALO Audio Rx MkII headphone amp ($399-$449)

• The iQube V1 costs between $100 and $150 more than the ALO Rx MkII.
• The iQube uses class D amplifier technology whereas the ALO is a conventional linear amplifier.
• Both amps uses very high quality parts, though the iQube arguably pushes the “parts quality envelope” even harder than the ALO does.
• The iQube uses USB ports as its charging source, whereas the ALO uses a conventional wall-wart type power supply. That said, however, the ALO sports a stout Lithium-ion battery pack that gives excellent playing time per charge, plus a cleverly conceived charging circuit that is said to promote long battery life.
• Both amps offer simply and comparably effective controls, though the ALO’s controls are generally more clearly labeled (the iQube uses symbols rather than words for switch and I/O jack labels, which look cool but may not offer the last word in clarity).
• Amp sections compared: the ALO offers levels of heartiness and richness comparable to those offered by the iQube, but with a greater emphasis on what might be called a smooth, “liquid sound.” The ALO’s highs sound lovely and are never mechanical sounding, though they are arguably not the last word in definition, articulation, or extension. By comparison, the iQube shows greater definition overall, a somewhat greater ability to delineate (or separate) individual musical lines, and more extended highs. But, as noted before, the prices of these positive qualities can be a subtle tendency toward treble dryness (though one that is much less obvious when using the iQube V1 or V2’s analog audio inputs rather than using the V2’s USB DAC input).

iQube V2 amp/DAC vs. CEntrance DAC Port ($399.95)

• The iQube V2 sells for a whopping $300 more than the CEntrance DAC Port.
• The iQube V2 amp section uses class D technology, whereas the CEntrance DAC Port provides a USB-powered pure class A amplifier.
• Very significantly, the iQube V2 is a portable device whose onboard batteries can be charged via a USB port. By comparison, the CEntrance DAC Port is not battery-powered and therefore is not designed for standalone use. In short, the DAC Port must be plugged into a USB port whenever it is powered up. Also significantly, the iQube V2 provides both analog audio and USB DAC inputs, where the DAC Port provides USB DAC inputs only. Together, these two factors make the iQube V2 usable in a number of contexts (for example, as a standalone amp for use with an iPod) where the DAC Port is unable to play.
• The iQube V2 DAC supports digital audio data streams at resolutions up to 16/48, while the DAC Port can handle data streams at up to 24/96 resolutions through both USB 1.0 and 2.0 ports.
• Both DAC sections feature solid jitter reduction technologies.
• Amp sections compared: the iQube amp offers a somewhat richer and more full-bodied sound than the DAC Port, but with touches of treble dryness. In contrast, the DAC Port amp is equally well controlled but more lightly balanced down low, but exhibits almost crystalline purity and sheer realism up high. The iQube sounds more comfortable driving a broader range of headphones than the DAC Port does, and is therefore the more capable and versatile amp.
• DAC sections compared: both DAC sections are good, but on the whole the DAC Port would get the nod, in part because its sound is so refined and well-defined, with nary a trace of the somewhat dry-sounding highs that the iQube sometimes exhibits. Add to this the fact that the DAC Port can handle high res files, which the iQube V2 cannot, and it becomes apparent that the CEntrance DAC section is the more capable performer overall.