Nordic news. Just upgraded to MkII with a new input buffer board plus very latest Sonic Imagery discrete opamps for a follow-up review, our Nord Acoustics nCore monos had transformed into prime SR1a material without any de-emphasis changes. At £1'730/pr, this potent pair in black or silver makes for a tidy cool-running package. With headphones, it's far easier on size, weight, temps and wallet than our hulking €6'500 Pass Labs XA-30.8 which still led this parade but to a now smaller degree. Despite really trying for unhappiness—just how perverse were those five words?—I couldn't muster any. With these switching amplifiers having noticeably gained in body and fullness over our previous iteration which I'd not really fancied, I could now happily recommend them as designated SR1a drivers even off something as quicksilvery, lit up and resolute as our COS D1 DAC/preamp. Whilst production will likely modify the impedance interface box with a three-pole toggle to add two simple de-emphasis options beyond the default, I personally had moved beyond considering them necessary or even desirable.

Concluding my adventure on this untraveled road deep into ribbon headfi meant moving downstairs again to meet the wizard of Oz, Vinnie Rossi's magnum opus of L2 DHT linestage with ultra-premium Japanese Takatsuki 300B. That would drive our mega bandwidth DC-coupled high-current LinnenberG Liszt monos into the original unswitched impedance box.

Down south. This deposited me in an ideal climate somewhere in the upper Mediterranean. Think spring time when everything is vibrant, balmy and lush well before summer's scorching heat dries everything out. Takatsuki glass liberated from output transformers and coupling caps really majors on speed, air, space, a lightness of being and certain vulnerability or fragility to completely rewrite 300B precedents. The L2 circuit then injects very mild softening from low 2nd-order THD aka octave doubling. Zero feedback bestows on music's motion through time a sense of suspended elasticity. This countered  the more rigid demeanor of class D. The German amps with their matte not glossy textures passed on this very refined DHT flavor whilst providing the Requisite current to the Raal ribbons. The result was truly superlative. It married top resolution for extreme insight with flow, elegance and highly developed staging to take me to places where I haven't heard other headphones go before. The Latin phrase is primus inter pares – first amongst equals. Aside from Susvara and Sonorous X, this group also includes the recently reviewed Empyrean. On magnification power, speed, linearity and dynamic willingness, the SR1a bested them all. As we know already, it also is the most critical about surrounding hardware and software quality.

Rightfully targeted at recording professionals due to their keen earfield monitor qualities, the Raal Requisite SR1a are equally capable of astonishing sophistication even mellow sweetness when strategically preceded by upscale high-end gear. Now they go well beyond those prosaic concerns that are wrapped up in 'just the facts' fears. Now they become equal to the best possible big hifi systems but without any of their issues of room interference, cabinet interference, port interference, crossover interference and the lot. To wrap up, I'm honored to have been entrusted with this first formal review on a new product which was in R&D for well more than 10 years and truly pushes a genre's boundaries whilst being legitimately different to accomplish its ambition. That responsibility justified taking the unusually long and windy scenic route to cover the whole story.

The SR1a are for the serious connoisseur who not only understands their technical concept, embraces the concomitant outré cosmetics and accepts the drive requirements but is prepared to acclimate to the consequences of a radical absence of common cavity resonances, energy storage and reflections. We're simply not used to such speed and unfettered dynamic reflexes, particularly not at 1cm off our ears. But once one gets recalibrated to the SR1a's view on what it means to do advanced headfi at this level, nothing else will ever look quite right again. That's a curse and a blessing. To find out which side you come down on, only an audition will do. And having proper ancillaries. And proper not crap music. In my book, the Raal Requisite SR1a are one of the most original forward-thinking innovations in no-compromise audio of the last decade!

Manufacturer's subsequent comment on the how: "Our true-ribbon SR1a are the first to combine a very lightweight diaphragm with a very low resonant frequency, the lowest yet in headphones. For several reasons this allows them to have better dynamics than anything made to date. Add to that the cleanest possible impulse response with the least amount of energy storage—lower than e-stats—and that's amazing resolution. This isn't about HF/LF extension or linearity. These more mundane things can be achieved in many other ways. It's about lack of dynamic compression and a clean impulse response, two unique properties of true ribbons. We also have the best control over the structural resonance of the diaphragm, again better than anything else including the thinnest of e-stats because we use viscoelastic damping in our dual-metal-layer ribbon. Our diaphragm is quiet, fast to accelerate and decelerate – not an easy combo to make. This is a genuinely novel take on the working parameters of headphone transducers."