There’s much to be said for portable headphone amplifiers that incorporate built-in DAC, especially if you use a laptop PC or MAC as your source component of choice from time to time. It also helps to know that some units are USB-powered (for example, the CEntrance DACport I recently reviewed in Playback), since this means you no longer need to lug a wall-wart type power supply/battery charger around with you when you travel.
But if you’re at all like me, you might want to do some listening through a laptop, but also to use an iPod or iPhone at other times. This would seem to point toward a need for high-quality portable headphone amp/DACs that meets the following core requirements:
· USB data interface for those times when you listen to music files from your laptop.
· USB power connections, just because they’re really convenient (at least as compared to a wall-wart type charger/power supply).
· A high-quality onboard DAC with a low-jitter USB interface.
· Battery power to handle those situations where you cannot, or do not want to, connect the amp to a USB power/data source.
· An analog input for those times when you listen to music stored on an iPod/iPhone.
· A high-quality (and preferable high-efficiency) amp to power your headphones—and ideally to power just about any type of headphone you might care to bring on the road with you.
At CanJam 2010 I spotted a headphone amp/DAC that met all of these requirements and then some, and knew immediate that I wanted to review it for Playback. The amp/DAC in question is the iQube V2 ($699) from the Dutch firm Qables.
The amp arrives in an adorable little rectangular tin (the kind you might expect to contain exotic European candies or cookies), and when first crack it’s container you’ll very likely be wowed by the iQube’s looks. It exhibits a certain precision and fineness of fit and finish that immediately reminded me of an old-school Leica camera from Germany. Our sample was done up in a tasteful two-tone matte silver and matte black finish, though I’m told there’s also a silver and white version available. The controls are simplicity itself to use.
On the iQube V2’s front panel you’ll find switches for amplifier gain (high or low), amplifier on/off, a control knob for the very high quality Alps volume control, and two pilot lights (one for power on, one to show when the unit is hooked up to a USB power source for charging. On the rear panel, you’ll find two mini-jacks (one for analog input signals, the other for the headphone outputs), and a mini-USB port (which, as mentioned above, serve not only to feed the DAC with digital data, but also acts as a “power cord” for charging the iQube V2’s batteries). That’s all there is to it: simple.
Of course things are quite so simple on the inside, where iQube has taken special pains to incorporate high-quality parts in all the right places. Highlights include:
· Medical graded double layer epoxy circuit board using HOFC (High Oxygen Free Copper)?
· Optimized board design enhances signal quality?
· Alps potentiometer?
· Vishay series 036 decoupling capacitors throughout?
· Panasonic stack film capacitors?
· Carbon signal resistors?
· Lumberg I/O connectors??
· Fully RoHS compliant?design.
· CNC machined aluminum casing, with rubber touch/feel painted covers
The iQube V2 design also incorporates:
· A high efficiency (90-95%) Class D amplifier,
· A built-in USB receiver and separate DAC?Tentlabs ultra low jitter clock generator,
· A built-in set of 4x AAA rechargeable batteries (non-user replaceable),
· An? 8-fold output buffer for a (near to) load independent output behavior,
· A? 4th order feedback loop for minimum distortion,
· A fixed, phase-shifted carrier wave oscillator said to decrease inter-channel distortion, and
· An ultra low noise front end that accepts any line level source without the need for impedance matching.
These highlights are no doubt appealing, but what really matters is the sound. I’m still in the getting-to-know-you phase with the iQube V2, but thus far it has really impressed me, in part because it has found a way to tread that oh-so-fine line between sounding open, airy, and revealing, on the one hand, but natural, full-bodied, and downright gutsy on the other. As I see it, that’s one of the very toughest sonic tightropes to walk, and yet the iQube V2 makes it look so easy.
One further point: if you like the basic idea of the iQube, but question your need for a built-in DAC, you’ll want to know that Qables offers a less expensive amp-only version called the iQube V1 ($549).
Stay tuned for an upcoming Playback review of the iQube V2.