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The iQube Enigma (Review Updated)

post #1 of 305
Thread Starter 
And he puzzled and puzzled, till his puzzler was sore.
Then the Grinch thought of something he hadn't before!

A Packageful of Paradox

Indeed, the iQube is quite a puzzle, and sort of a slippery customer to boot, its clever non-skid, protective outer armor notwithstanding. Ignoring, for the moment, that even the most basic act of opening the unit to replace its batteries is a mind-bender worthy of Ernő Rubik himself, the iQube appears to possess the singular power to haunt and cloud Head-Fiers' minds.

Well, at least my mind for starters. Having spent nearly a month in the iQube’s company, beguiled by its Bauhaus-inspired aesthetics, undeniably solid heft, OCD-infectious tactility, astonishing quickness, power & transparency, still I can't help but find myself struggling to write about it, such is its lingering spell. So I hope that posting this here may finally allow me to shake the iQube’s wicked hoodoo; I returned the damned thing over 3 weeks ago, bejeebzus, so here goes…

Happily, the packaging of the iQube is easy enough for a child to open! In fact, my 5 year-old accomplished the deed in no time and eagerly helped me to construct the tiny towers depicted above. Come to think of it, maybe I should've enlisted him to tackle that pesky battery compartment...

A Saucerful of Secrets

Our next iQube incongruity concerns its appearance. For me, it is elusive and guards more than its share of little secrets. I don’t know whether or not it’s down to its own particular design elements, choice of materials, or color scheme, but the iQube simply refuses to photograph well. Invariably, in every picture I’ve either seen or taken of it, its matte aluminum looks plasticky, and the iQube as a whole comes off more like a nice enough CAD-rendering that one might expect to find at a digital art school exhibit.

Approach the iQube in the flesh, however, and this hate-hate relationship with the camera becomes emphatically obvious. Considering it simply as an object, I quickly discovered that the iQube demands nothing less than devotional attention, like some kind of otherworldly apparition. Smart clean lines, seductive curves, drum-tight fit & finish (just 2 screws!), and a most perfect expression of symmetry that remained otherwise obscured in the two-dimensional realm suddenly leap to the fore, taking on a life all their own.

And, OMG, the sheer feel of it all! The assortment of textures on offer here is a tactile feast of the highest order. With the cool solidity of its impossibly smooth aluminum front & rear chassis merging into the slightly spongy, black rubberized-alu top & bottom panels, the silken travel of its volume pot contrasting the tight, decisive throws of those twin toggle-switches, precision engraving, recessed LEDs, and flush-laying jack-array (input/output/recharge) secluded around the back, fondling the iQube seems nothing short of scandalous.

Factoring-in its centered battery receptacle ensuring absolutely even weight-distribution, the iQube achieves a satisfying sense of balance quite unlike any other portable amp I've ever had the pleasure of hoisting.

iQube, iQuizzical, a brief interlude…

The iQube holds the distinction of being the first (and thus far, to my knowledge, only) battery-operated portable headphone amplifier employing a Class D topology. And yet, even though it was introduced just a short couple of months ago, one needs to utilize the search function here to read anything much about it.

The iQube's circuitry designers, Bruno Putzeys (Hypex UcD / Grimm Audio) and Guido Tent (TentLabs / Grimm Audio), have consistently released consumer and professional grade Class D modules and related modification solutions (amps, DACs, CD players, etc.) that generate tremendous interest around the likes of diyAudio Forums, 6moons, et al. Nonetheless, while it has recently hovered near the very top of Skylab’s Portable amp roundup!, the iQube remains fairly aloof from the larger discussion here, failing to muster anything even remotely approaching the zeitgeist currently enjoyed by the likes of the Pico, LISA III, Predator, iBassos D1, D2 & P2, Corda Moves, etc.

So what happened?

Well, despite an insidiously clever and fastidiously comprehensive roll-out campaign (pre-sale discounts, package deals with select headphones, attractive dedicated website complete with flash-based teaser-glimpses, release date countdown clock, etc.) that was essentially unprecedented for any single headphone amplifier that I can recall, the timing could not have been less fortunate. At virtually the very same moment that the iQube countdown clock ticked over to zero signaling its official availability, Head-Fi suddenly went dark for weeks. And weeks. Curiouser and curiouser!

The iQube also fell victim to the ever-weakening U.S. currency situation. One need only read Sky's price caveat toward the end of his iQube blurb to understand that the larger perception of the iQube is inevitably bound to be influenced by its affordability outside of Europe.

Nonetheless, we can easily ascertain from this thread over on the Qables sponsor forum that the first batch of iQubes sold through after just over a month, so hardly a disaster by any stretch. However, I can still find only about three sets of extensive impressions here other than Skylab's, so either the vast majority were sent to non-HF members (and, frankly, I suspect that more than a few made their merry way to the Far East...) or their recipients are simply too absorbed by their new iQube to post, so the mystery continues apace...


In use, the iQube takes a little getting used to. While the input/output jacks around-the-rear thing seemed counterintuitive at first, I eventually began to appreciate the idea of having the front controls free of cable-clutter. And utilizing the included rubber-strap made for a nice secure interface with my 5G iPod in road-warrior mode.

My first task was to compare the iQube to my iBasso D1 and P2. The iQube arrived to me fully burned-in, according to Hans, though I’m uncertain of the exact number of hours that it had been used previously. And the iBassos had already logged well over 500 hours each.

Perhaps the most interesting surprise for me, in taking the iQube out and about, is the synergy that it demonstrates with my PROline 650s and HFI-650s. Now, these are not usually considered to be difficult cans to drive by any means. At 75 Ohms, they can make for a pleasant enough listening experience driven directly from an iPod. But they certainly do respond favorably to amplification, and I had noticed that they had been struggling just a bit with my iBassos, requiring the volume pot to linger anywhere between the range of 2 to 4 o'clock in order to receive sufficient voltage to achieve the depth that I know they're capable of.

No such difficulties were to be heard with the iQube, however, which had the PROline 650s scaling up to such a remarkable degree that I found myself resisting the urge to double-check and make sure that it wasn't the PROline 750s I had on my head.

Back home, it was, of course, much easier to directly compare these three, with the fine DAC section of the D1 supplying Apple Lossless files from my Mac mini.

I've really been enjoying my D1 (HiFlight op-amp modded) & P2 (stock). They're quite a versatile pair of amps to have on call, with a liquidy midrange and plenty of bass oomph, and they share the ability to deliver ample current to drive my Edition 9s easily. Owing to the requirements placed upon it by its on-board DAC, however, the D1 is left just a little wanting in the voltage-delivery department, hence the issue with the higher-impedance 650s as described above. Not exactly a critical shortcoming, but not ideal either since it has led to all that op-amp rolling insanity in attempting to redress the balance (thank goodness it works! ). The P2 is a little more fit & forget, and a truly remarkable amplifier belying its diminutive size. And I still haven't quite decided exactly which I prefer from purely an amplification perspective...

Placed in the company of the iQube, however, this consideration dissolves into irrelevance. The iQube is just simply a breed apart.

As well it should be, considering the differences in price. But it is also here that the distinctions offered by the iQube's Class D module began to make themselves known. The effective headroom is nothing short of stunning, giving the impression of limitless power reserves on tap at all times. And the speed that the iQube demonstrates in capturing the leading edge of notes is on par with the Edition 9s’ ability to deliver them, leaving the iBassos suddenly sounding uncharacteristically sluggish.

Then there's the issue of power management. One of the main reasons that the iBassos are able to supply such a high current output in proportion to their modest size is that their power supplies take advantage of continuing advancements in Lithium ion batteries. The downside of this is that they can also be a rather finicky proposition.

Li-ions have a finite number of charge/discharge cycles and their capacity degrades inexorably over their lifetime, regardless of hours in actual use. They are also at risk of deep-discharging from which they never fully recover. And they are often not easily user-replaceable, as in the case of the D1 and P2. Of course, the iBassos boast some kind of protection circuitry along with low-battery indicators, but nonetheless the various iBasso threads here have seen more than just a few reports of battery-related issues and anomalies. While my D1 and P2 continue to be just fine (knock-wood), I'd prefer not to be waiting for the other shoe to drop...

The iQube, on the other hand, is so highly efficient (90-95%), that it can deliver plenty of current and voltage and is designed to perform optimally with either 4 ordinary AAA alkalines or NiMH rechargeables. And the 94 hours of peak performance I got out of the iQube before the low-battery indicator began to illuminate ain’t too shabby, neither.

I can also remember some early discussions where folks were wondering whether or not Class D might be "gimmicky" or "overkill", with regard to headphone amplification and its specific demands. And, indeed, in a less fully realized design than the iQube, I suppose that certainly could be. But spending some quality time with it tells me that Team iQube did their homework and that there's something pretty special going on here...

iQandy: Reunion @ Club Pretty-Boy

I'd like to fast-forward, for just a moment, to when I returned the iQube to Hans. Back in the cozy confines of his shop, audioXperience, I seized the opportunity to snap a few candids of the iQube alongside two of its more blingtastic pals.

Of course, the LaRocco PRII (mkII) is a genuine classic and effortlessly lives up to its stellar reputation. If it's on the large side of "portable", it is only just so, and anyone with sufficient rucksack real estate and willing shoulders would be thrilled to tote one around. Plugging in my Edition 9s for a quick comparative listen, the PRII was every bit as involving as I remembered it being from my previous visit, lush and expansive, with impressive command and keen insight into the performance.

But the iQube proved more than capable of holding its own in the face of such esteemed company, delivering a cooler sense of authority characterized by its own signature speed and transparency, particularly in rendering transient passages. I'd truly be hard-pressed to choose between these two dynamos; if the PRII holds a slim edge in the excitement stakes, the iQube states its case via a slightly more nuanced sense of organic grace.

Unfortunately, the Diablo had arrived to Hans D.O.A., so I was unable to cop a listen. What did strike me, however, is that it demonstrates the flipside of the photogenic puzzler I postulated earlier here. In other words, the Diablo photographs beautifully, but I found it to be rather disappointingly executed in person. Indeed, it is surprisingly lighter than I was expecting it might be, yet not as satisfyingly balanced as the PRII or iQube, and with a bit of a lopsided feel to it. The brushed aluminum body has a rough, unfinished texture to it and clearly would have benefited tremendously from at least some kind of minimal anodizing, as found on the PRII.

Moreover, the edges on the front and rear panels are just ridiculously sharp. Since these are not flush with the Diablo's chassis, there are sixteen such edges. So while I can easily imagine someone using their Diablo to slice steak in a pinch, it's not a terribly practical feature for extending the life expectancy of one's backpack, portable player finish, or cabling, let alone fingertips. Medic!

If the whole Diablo saga is a cautionary tale for consumers and vendors alike, actually handling one provides such stark contrast to the PRII and the iQube, it only allows me to appreciate their respective charms even more.

iQube? ¡iQaramba!

Now that we've gotten a wee bit ahead of ourselves here, let's return back again to where the iQube handily showed a clean pair of heels to both of the iBassos. Since it was abundantly clear to me that the iQube is one of the very best portable amplifiers I've ever encountered, the only challenge I had left to offer was to pit it against my desktop amp.

For any of you who might be unfamiliar with it, the Heed Audio CanAmp enjoyed a remarkable run around these parts for the better part of a year. It punches well above its asking price and was indeed "the little home amp that could", so to speak, until it fell out of fashion, as all things eventually must do. Regardless, I remain smitten with mine. To me, especially with my lower-impedance Ultrasones, the CanAmp has that rare ability to just step aside and allow music to flow through, without imposing much of itself upon it. I'm aware of its presence mainly by the fact that it has a volume pot through which to throttle the proceedings. And with a Class A output stage, the CanAmp never exactly seems wanting for power. So how can any portable, let alone one the size of the iQube, even hope to compete?

Well, once again, the iQube showed me that there's much more to properly implemented Class D on offer than fantastic battery life. Dropped into my living room system and utterly dwarfed by the sources surrounding it (Ah! Njoe Tjoeb CD 4000 Reference, Roksan Xerxes.20 turntable), the game was afoot!

Starting with vinyl, Pink Floyd's "Us And Them" is often my very first port-of-call for comparative listening on the big rig, since its crescendos ("Forward he cried..." / "Haven't you heard...") are an absolute minefield for just about any piece of kit to negotiate easily. Less capable equipment tends to smear the voices and instruments together into an unflattering sonic soup. But like the CanAmp before it, the iQube effortlessly answers the call with quickness and finesse.

Although my mono pressing of Time Out by the Dave Brubeck Quartet is one of the best arguments against stereo that I care to imagine, it remains a difficult proposition for any headphone/amp combination to translate the attack, spaciousness and immediacy of this classic session. The foundation of this album is rhythm and punctuation; acoustic stabs, rolls, and fills, and the interplay in-between. Both the CanAmp and the iQube faithfully transcribe Brubeck's rollicking piano, Paul Desmond's intricate alto figures, and Joe Morello's magnificent crash-cymbal rides. The slight difference here has more to do with depth of soundstage. If the Edition 9/CanAmp pairing has always taken me into the seat next to producer Teo Macero (R.I.P.), the Edition 9/iQube places me just a chair or two behind. Not a bad thing, mind you, it's still great to be in the room!

As I mentioned earlier, the leading edges of notes as rendered by the iQube are fast, yet well defined. “Beautiful Bluebird”, the opening track from Neil Young’s latest album, Chrome Dreams II, is a gorgeous acoustic number, awash in guitar, dobro, harmonica and trap-drum. Neil’s quavering vocal rides somewhat above the fray while remaining entirely integral to it. The iQube demonstrates marvelous aplomb in reproducing the strike of every plectrum as distinct and musically compelling in the context of the performance.

Moving back and forth between the CanAmp and iQube proves to be an exercise in frustration and surprise. Frustration in that, while listening for varying musical elements on the CanAmp, I’m confident that it’s gonna have the iQube beat (“gotcha now, iQube!”), only to find that time and time again, the iQube rises to the challenge and equals the CanAmp in virtually every respect. The CanAmp has a bit more depth of soundstage, and I think the iQube may be just a tad more neutral, but we're approaching hair-splitting territory.

So, Riddle Me This: Premium Portable or Home Amp in Your Pocket?

And therein lies the surprise and delight of the iQube. I’d conservatively estimate that one could fit the iQube eight times over into the footprint of a single CanAmp, and yet, for my own requirements, Hans & Co. have managed to effectively wedge a formidable home amplifier into a package less than the size of a discreet card-shark’s whiskey-flask. And Steve Jobs thinks he’s onto something special with the MacBook Air in the miniaturization sweepstakes?

Since I joined Head-Fi in August, 2006, it seems that we've increasingly become spoiled for choice, especially where portable amplifiers are concerned. That first little Go-Vibe of mine already feels like half a lifetime ago. It is easier than ever before to get incredible sound from relatively cheap 'n' cheerful amps like the iBassos, MiniBox E, etc., and additional amenities such as the DACs on-board the Pico, Predator, and D2 in ever-vanishingly smaller housings. So, naturally, our expectations of value for money have tended to skew accordingly.

If anything, the iQube flies rather boldly in the face of these trends. It is a premium high-fidelity component through and through; a seamless merger of iconic design elements, of elegant functionality, of impeccably selected materials, and of robust construction. Yes, it is only an amp, but oh what an amp it is!

So, as I've sat puzzling the iQube's implementation of Class D these many weeks now, it becomes clearer to me that there will inevitably be other examples of it sure to follow. Whether or not Class D effectively reinvents some paradigms of headphone amplification and their possibilities, or even sparks a gradual shift in its direction among amp builders, remains to be seen.

The iQube is not inexpensive. But real innovation carries its price, too. For the time being, and in so many satisfyingly different ways, the iQube stands resolutely apart from the pack.

Postscript 3/18/08:

My Own Private i(da)Qube!

I'm pleased to report that I finally purchased an iQube at the Netherlands Meet (aka DutchJam '08), where Hans was offering a "Meet Special" that was just too attractive to pass up! Sure, I'd been setting some funds aside since I originally returned the review sample, but make no mistake, Mrs. Dex will kill me should she ever discover how much these things actually cost! But since I had already effectively characterized the iQube's sound as "to die for", I suppose that's only appropriate...

The real clincher for me was having the opportunity to compare the iQube to the Graham Slee Voyager that Hans had in the house. Now, the Voyager is an absolutely superb little amp, and I have to say I was shocked at how lovely it sounded, especially considering its rather undistinguished (and that's perhaps being overly kind...) feel and appearance. But with my Edition 9s and PROline 2500s, I found the Voyager to be on the warm/dark side of neutral for my taste (and very similar indeed to the LaRocco PRII [mk2]). So, once again, the iQube managed to carry the day. And I carried home iQube #20080140 (though I've already begun calling it "140", for short! ).

It took me about an hour in front of the telly that evening to open it up for the very first time. Fortunately, I took the precaution of trimming my fingernails beforehand to avoid scratching the rubberized paint as I struggled, grunted and groaned! In the iQube manual, it states: "After a few times opening and closing the unit, the locking construction will become easier to open." So, finally having achieved victory, I set about gently massaging (extra emphasis here on "gently") the 3 plastic clips on the chassis, in order to "fool" the unsuspecting iQube into thinking that it had been already opened-up on numerous occasions.*

Result? I can now do the deed reliably in about 5 seconds!

Here's a photo of the correct opening orientation highlighting those 3 plastic locking clips:

*Disclaimer: Hans informs me that excessive rubbing of the three clips can result in a loosened interface of the battery-compartment cover and cause undesirable "rattling" to occur. So exercise extreme caution as you exercise the clips; work them very gently and gradually, replacing the cover frequently to assess your progress, until the correct degree of suppleness is achieved for "easy-opening", while still allowing for a nice tight cover/chassis interface.

Updated 3/19/08

iQube Battery Compartment Opening Tutorial

If the battery compartment unlocking method as described in the iQube owner's manual brings you no joy, here is an alternative route:

- Hold the iQube in your hands with the bottom of the unit (the black rubberized battery cover) facing outwards. The front volume knob/switches should be pointing into your left palm, while the rear input/output jacks should be pointing into your right palm. The engraved "iQube" logo in the side-rail of the chassis will be upside down as you look downward.

- Place both of your thumbs directly over the black rubberized area where the first, lone clip is located (the corner closest to the "output" jack, Clip 1, as shown above circled in green).

- Push downward and outward simultaneously. The first side should "click" and come free.

- Press this side partially closed again (with your thumb over the portion where there isn't a clip underneath) until you hear a very slight "thuck". There should be a discernible gap of about 1mm between the cover and the chassis.

- Rotate the iQube to the opposite side. The front volume knob/switches will now be pointing into your right palm, while the rear input/output jacks should be pointing into your left palm. Again, the engraved "iQube" logo in the side-rail of the chassis will be upside down.

- Place your left thumb over Clip 2 (above in blue) and your right thumb over Clip 3 (above in pink) on the black rubberized surface.

- Again, push downward and outward simultaneously. The second side should "click" and the entire battery compartment cover should come free.

- With the cover off, try the clip massaging technique as I have outlined in the previous section, so that subsequent openings become noticeably easier.

- After changing the batteries, replace the battery cover on the side with Clips 2 & 3 first. Snap the cover into place on that side, and then snap down the opposite side where Clip 1 is located. Job done!

Note: The iQube battery cover is perfectly symmetrical, so it does not matter whether or not the original orientation is maintained when replacing it.

Update 3/21/08

iQube Opening Video Tutorial Now On YouTube!

Click HERE.

6moons iQube Review

The review was conducted by Marja Vanderloo & Henk "LongBeard" Boot. It provides some fascinating insight into the origins and development of the iQube as discussed above, with particular attention paid to its Class D topology.

Click HERE.
post #2 of 305
Very good, Dex!
I'm enjoying the reading, definitely a great review.
post #3 of 305
Very good read...
post #4 of 305
I loved reading this professional review which any mag would pay for such a well written review, thanks.
post #5 of 305
the iQube is around 600 USD I believe
post #6 of 305
Beautifully written, send me a pm though to tell me how to open the damn thing to change the batteries.

Managed it once, but cant open it again. Damn, that is a rubiks esque puzzler.
post #7 of 305
Holy cow, that was a great review with great pictures to match.

Thanks for taking the time to make the review come alive.
post #8 of 305
How does it do with 300 ohm cans?

post #9 of 305
Lovely written review! Looking forward comparing it to my Larocco at the meet. It almost sounds to good to be true.

On a sidenote: that Diablo looks real ugly with its weird volumeknobs and sharp unrounded borders and corners.
post #10 of 305
Very nice review. I really like your writing style. Enjoyed reading it !
post #11 of 305
nice review! loved the rubik's cube mesh pic!
post #12 of 305
Originally Posted by Joelc87 View Post
the iQube is around 600 USD I believe
At the current rate it is only 500US$ (335euro)

post #13 of 305
Originally Posted by hoosterw View Post
At the current rate it is only 500US$ (335euro)

Pity it doesn't come with a DAC. Or better yet, pity it isn't class D digital, so it would essentially BE a high-power DAC. I've got to assume, given all the talk about efficiency and volts that this would be a portable particularly well-suited to 300 ohm Senns? Yes, no, mabye?

post #14 of 305
Thread Starter 
First off, thanks everybody for your kind feedback!

Originally Posted by XTC View Post
How much does that thing cost?
Here in Europe, it lists for €399, which includes the requisite exorbitant 19% VAT (value-added-tax). So outside of Europe, it is €335, which converts to about $509.

I know from this thread over on the Qables sponsor forum that Hans has recently begun a relationship with a fellow in the States to sell his cable ranges, but excluding the iQube. But if there was enough interest, perhaps Hans could be leaned-on a little to arrange a group-buy at a more attractive price. I have no idea whether he would be amenable to such a thing, so it's just a thought...

Originally Posted by dazzer1975 View Post
Beautifully written, send me a pm though to tell me how to open the damn thing to change the batteries.

Managed it once, but cant open it again. Damn, that is a rubiks esque puzzler.
Heh-heh, dazzer, I only had to do the deed once myself...and it wasn't easy! I just followed the printed instructions, grunted a lot, and eventually the iQube caved to in my sheer force of will...

Originally Posted by tfarney View Post
How does it do with 300 ohm cans?

Good question, Tim, but I haven't any truly high-impedance cans around. My next encounter with the iQube will be at the Netherlands Meet on the 16th and there will certainly be some HD650s, DT880, DT990, etc. for me to try out there with it.

In the meantime, I'm hoping that some of those shy, closeted current iQube owners out there will feel encouraged to represent their experiences here.
post #15 of 305
Wow, I enjoyed that review for the language as much as the content. Great stuff. I love the iQube, its the one true portable amp that has got me interested. I would have jumped on one had I not been able to grab the LISA III for cheaper and wanted to get a desktop before a better portable. It truly deserves the ranting more then the PICO or certain other FOM amps IMO.

I wish its costs weren't so prohibative. That is the best (truly) portable amp on the market IMO.

PS: Moon-Audio down the road is negotiating a deal to distribute the iQube in the US. That is how I reviewed it.
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