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Icon luv. It's not often that manufacturers dole out enthusiastic endorsements. Amphion's Anssi Hyvönen from Finland had been chasing cheap but quality ancillaries for ages to get the best from his speakers in systems everyone can afford: "I see Jason sent you the HDP. I have played with it. It's pretty amazing and can be used quite a few ways. I have for example put together an HDP/Icon amp/Amphion Ion system with proper cabling. Some of our top recording guys will start using this setup in studios and for location monitoring. You would have fun auditioning our Ions in this context. That's quite a cool-looking reference system with an amazingly good midrange (a completely different level of vocal-band resolution than the Helium 510 you reviewed)." Duly noted, review booked exactly as suggested. Stylish high-performance desk top propositions factor big on my motivation meter.

Headphone amp, USB DAC, preamp. Priced and sized for the desk top, running the HDP through its paces mandated proper playmates. Because my desk top rig is anchored by the overachieving Peachtree Audio iDecco with its digital-direct iPod dock hardwired to a cracking ESS Sabre DAC, I had my ideal default source through its fixed outputs. The iDecco further has headphone and USB sockets to square off two more feature comparisons. Done.

For headphone performance, I pulled out the stops and my best full-size cans, ALO Audio-rewired beyerdynamic T1 and Sennheiser HD800. An AIFF/WAV-loaded Apple MacBook Pro would do USB. For preamp action, I'd again compare iDecco and HDP over two surprisingly good small amplifiers, the MiniWatt N3 and Dayens Ampino with their please-improve passive pots. Speakers appropriate for the desk-top nearfield were my usual era design 5 SAT plus the Dayens Tizo above. Cabling was ALO Audio stranded cryo copper for signal, Crystal Cable Ultra for power. AC conditioning came from Furutech's e-TP80. From what I had on hand, these were the most appropriate component ancillaries. They'd test ambition without going overboard into a context no paying customer would ever replicate or hear - except for the 'phones perhaps. As we'll see though, the HDP is intended for the best. Cannery row.

As headphone amp: The HDP was a tad crisper, a bit more upfront and somewhat more poignant than the iDecco which felt very moderately laid-back and a degree softer by comparison. The NuForce transients were peppery for higher blister while subjectively grippier drive created more bass snap. These differences were far from pronounced but still quite easily identifiable. Very clearly the HDP's top end was more lit up. The NuForce also had more gain.

The iDecco/Sennheiser vs. NuForce/beyerdynamic combos seriously diluted these distinctions. That's because the T1's voicing is closer to the iDecco's, the Sennheiser's closer to the HDP's. Crisscrossing the candidates created a very equal give & take. Mating like with like emphasized the differences. The more voluptuous and smoky HE-5LE orthodynamics from HifiMan were better complimented by the NuForce's more quicksilvery upper half. Particularly coming off the somewhat high-strung dialed-for-speed HD800, the comfy planar-magnetic presentation needed a kick in the arse. The HDP delivered that boot. In matters of headstaging, the NuForce's subjectively higher focus had more of a spot-lit effect on stage central. The iDecco's fluffier looser personality seemed to stretch things sideways more.

The surprise here was the tone/density part of the equation. Particularly the original NuForce stuff always seemed hyper detailed, dry and harmonically bereft to my ears. The HDP transcends this trend nearly wholesale. Such a morphed personality parallels comments on the latest Wilson sound. Warmth and density listeners who found it wanting before now praise it quite unanimously.

While I haven't heard any V3 NuForce to know whether the team has implemented a corporate shift in house sound, the HDP certainly does very much not remind me of the early NuForce sound - except for noise floor. Here the latest li'l black box seems very ambitious to create intense contrast ratio. Gobs of detail we know from NuForce. This dash of embedded but utterly non-fuzzy and focused minor warmth is a new wrinkle. If you take with you just one core impression from this review, I'd have it be this shift of feel or personality.

It goes counter to popular class D perceptions and certainly NuForce implementations. That makes it significant. Saying it differently, most headfiers regard Woo Audio's mighty Model 5 300B SET very highly. I own the Premium Edition with the designer VCap, BlackGate and Jensen caps, Mills and Kiwame resistors. Plus I have plenty of top bottles to roll in - Western Electric, Shuguang Black Treasure, Synergy Hifi, EAT, Emission Labs XLS. The works. The HDP is as good as the Woo - not same but different good.

Where the valves rule is scale and scope. They simply sound bigger, more expansive and gushing. They enfold all the information in a context of flow and their macro dynamics crest taller. Bigger waves. Flow is key, detail seemingly gets carried away in it. The class A integrated output chip in the NuForce retaliates with lower body fat, more pep, shinier more informative upper octaves and a closer look at detail. It's undoubtedly drier but far less so than anticipated. That's the real surprise. Rather than trading detail for density to introduce this new warmth, the HDP maintains the microscope but adds a shot of mass. Listener preferences and ancillaries always make the final call. I simply think that it'll be the rare auditioner who sonically calls the NuForce in a flat-out lower league. Once you factor in pesos and rubles, things get quite silly.

As described, the NuForce is a few whiffs more 'organic' than the drier cooler Corda Concerto and even the fully discrete 'we hate op amps' Burson HA-160. If nothing else, it's a reminder that parts and topology racism are silly. Superiority claims for specific classes of operation too can quickly degrade into an antiquated caste system. Finally, the HDP is sufficiently potent and suave to really drive bad-boy 'phones properly. Very much in its favor and further proof of the novel minor warmth factor was the showing with my AKG K-702 [lower right]. This is a very neutral and quite hard-to-drive headphone. By tendency it will sound flat and boring unless the amp lifts it to a more involving plateau. Then it downshifts a gear for more excitement where dynamic reflexes and low-bass punch wake up. And that's exactly what the HDP did. Additionally, recorded ambience blossomed behind and around the performers to inject the third dimension. At $549 with a 6-foot leash of ALO Audio SXC cryo cable, the AKG actually is a very sane HDP mate (the T1 and HD800 clock in beyond a grand). Precisely because it's demanding on both drive and 'X factor' from the amp, I don't often single out the K-702 for recommendation. Unless I personally know the prospective buyer's amp, I can't know whether it'll have that X factor which injects that undefinable but easy-to-hear juiciness these 'phones need. What about the NuForce circuit does this business I have no idea, exactly. But it does. The rewired K-702 becomes a natural-born killer mate.

If you run the HD800 with its stock wiring, you'll want intrinsically mellower interconnects to tone down their zippy top end and zingy response. The NuForce will not neutralize it. While unapologetically nuts, a brief detour into Stealth Indra exotica proved just how important wires become when circuits and transducers get this revealing and 'hardwired' to our ears. Without giving up any speed, this ultra-thin amorphous (glass-like) wire completely took out the artificial edge or sheen of lesser cables to show how that type flavor is not built into the HDP. How to replicate Indra type cable flavor at Icon pennies?

I'd perhaps look at the Van den Hul Integration Hybrid. At €198.50 for 80cm, it still might seem dear in context—though you'll only need one— but the Indra proved that the NuForce deserves top cables. Another trick is running your iPod with uncompressed files directly into the HDP. The losses in immediacy and energy create a mellowing action compared to more highly resolved external converters like the iDecco. Tapping an iPod through a quality dock like the Sieben bypasses its volume control. The result are sonics snooty audiophiles fail to acknowledge but smart-money shoppers shouldn't overlook.

Adding up Round I: At $449 for just the headphone function, the NuForce would be a real contender. It's far smaller than the Burson and not remotely as tank-like. On capacitor bragging rights, it's crushed by the Corda Concerto. On face plate envy, the score is nil to two for the KingRex HeadQuarters. But the Icon is as solid a choice on performance as any of those. Where things get hairy is that NuForce adds the preamp output, switchable inputs and USB DAC. None of the others offer that much extra. Next.