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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 2TB iMac 27" quad-core with 16GB of RAM (AIFF) running OSX 10.8.2 and PureMusic 1.94g in hybrid memory play with pre-allocated RAM, Audirvana 1.5.10 in direct/integer mode 1, Metrum Hex, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2s, AURALiC Vega, Apple iPod Classic 160 AIFF-loaded, Cambridge Audio iD100, Pure i20, Pro-Ject Dock Box S Digital, RWA-modifed Astell&Kern AK100
Preamplifier: Nagra Jazz, Bent, Audio Tap-X, Esoteric C-03
Power & integrated amplifiers: FirstWatt S1 monos, SIT2; Crayon Audio CFA-02, Bakoon AMP-12R, Goldmund/Job 225, Gato DIA-250, Clones 25i [on loan], Aura Note Premier
Loudspeakers: soundkaos Wave 40, Boenicke Audio W5, German Physiks HRS-120, AudioSolutions Rhapsody 200, Zu Audio Submission
Cables: Complete Zu Event loom; KingRex uArt, Zu Event and Light Harmonic LightSpeed split USB cables; Tombo Trøn S/PDIF; Van den Hul AES/EBU; AudioQuest Diamond glass-fiber Toslink
Powerline conditioning: GigaWatt PF-2 + Vibex Two 1R on amps, Vibex Three 11R on front-end components
Headphone amps: April Music Eximus DP1, Stello HP100 MkII [on review], Burson Audio Conductor, Bakoon AMP-12R
Headphones: ALO-recabled Audeze LCD-2 & LCD-3, Sennheiser HD800, beyerdynamic T1 and T5p, AKH K702; stock-wired HifiMan HE500 & HE6; Aëdle VK-1
Equipment rack: Artesania Exoteryc double-wide three tier with optional glass shelf, Rajasthani hardwood rack for amps
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Desktop system: iPod/AK100 digital transports, Wyred4Sound minT, Gato Audio DIA-250, Gallo Strada II + TR-3D
Room size: Irregularly shaped 9.5 x 9.5m open floor plan combines the living/listening room, kitchen and office. Added to this space the speakers see the air volume of the entry hall and a long corridor plus the 2nd-storey 6 x 9.5m loft. Wood-panel ceiling slopes up to the loft. Parquet flooring. Lots of non-parallel surfaces ('vertical gable' windows, twin-angle ceiling, spiral staircase enclosure, fireplace enclosure).
Review component retail: €1'650 for amp, €1'750 for headphones

Aberration. I'm no linguist, cunning or otherwise. The word's similarity to the German aber for 'but' is simply suggestive. A ration of but which breaks with norms or conventions. But still it exists. Consider the Japanese TakeT H2+ from Takei-San. This headphone presents any amp that would drive it with a 5~7kΩ impedance. This shows how it just shouldn't. Exist. Yet it does. An aberration. Additionally its (in)efficiency means that it needs about 4 watts to get up. To make that work—somehow—its designer provides outboard matching transformers to better meet his extreme impedance and let regular speaker amps do the heavy lifting. It does make one wonder though. Who as yet has really heard the H2+ at its very best? With such steep input impedance, power transfer of amps designed for 8Ω speakers or 50-600Ω headphones becomes painfully inefficient. Do we imagine faint echoes of AKG's K1000 of yore?

Enter the ever resourceful Sasa Cokic of Trafomatic Audio. He first encountered the TakeTs during a Norwegian hifi show hosted by his domestic importer Moiz Audio. Impressed with their promise, he's since built a matching valve amp. It runs two single-ended UL-strapped EL34 driven by two ECC88. "The extreme H2+ Ω presents an ideal situation for an unusual output transformer. For once we don't step down the impedance of the power tubes at all. The particular OPT required to do the trick simply turned out even more complicated than the already very complex interstage transformer for your Kaivalya monos. So you see, I'm never short on funny."
Amplifier prototype testing on one channel.
Funny is Sasa code for taking on challenging projects just because. He had another funny in a 10Y custom preamp for a friend of mine. For that project he still chased down circuit noise, being on the 3rd enclosure iteration already and going into the 4th. My Kaivalya IT took seven prototypes. We all get our kicks in peculiar ways. Sasa is one hilarious guy.
Piezo super tweeters close [left] and open [right].

Back to the 360-gram light headphone. Its TAT core driver is a polymer piezo-electric. It's described as being related to Oscar Heil's AMT. But that suggests pleats which Sasa who opened one up says aren't there. The main piezo drivers are augmented by two super tweeters which can fire forward and outside of each cup to increase the subjective size of the headstage. The designer's experience with piezo drivers dates back some 20 years to a speaker he designed for Sony. Its 80dB sensitivity meant that it never went into formal production. Having left Sony 5 years ago, he has since revisited his fascination with piezo tech. The limited production H2+ headphone in its laboratory-grade hard plastic chic is the final result.