In my headfi circles, HifiMan's Susvara are the most electrostatic of planars. That makes them counterpoint to the far chewier more chocolaty pre-Fazor Audeze LCD-2 and later closed-back LCD-X; and far quicker and more lucid than any of MrSpeaker's Fostex-based orthodynamic oldies. As such, it stood to reason that Susvara would take this mellower tubular action not only in stride but actually benefit particularly with hotter Pop's distorted e-guitars and close-up vocals; or during the stridency of cyborg Techno with its metronomic drum machines and manufactured industrial synth effects. For headfi, my default DAC/amp is the COS Engineering H1 with its 2 x 3-pin XLR/6.3mm combo jacks; and custom balanced leashes from ALO Audio and Forza Audio Works. For pure 6.3mm drive, our very best is the 15wpc Bakoon AMP-12R. Against those precedents, Euforia's fine echoic fill now compressed to some 22cm between the ears rather than spread across a 4-metre wide speaker stage to be diluted. That created a very meaty midrange-out perspective with plenty of material substance. Flicking the crossfeed rocker to 'on' piled on even more filler to have me quickly turn it off again. The denser the musical melée, the stronger the wet effect grew. I thus found it finest on minimalist ECM-type fare played low. As the head count of virtual performers escalated and/or the volume raised, so did the hydra effect of billowy overlaid haloes. As a result, the thinnest treble trails felt damped and even walloping bass transients were enfolded in the heightened quasi reverberant field. That's how the frequency extremes separated out less clearly and with less power than they do over our transistors. Flipped on its head, the same observation would call out a more pronounced built-out midrange as the bandwidth across with the majority of the musical action occurs. Now more equals more and followers of that view would call it better to applaud Euforia's reading.

Soundaware D100 Pro SD card reader via AES/EBU to Aqua Hifi Formula DAC, then RCA to Euforia.

With their stock thick twisted cables, both our transistor amps paint Final's new 98dB/60Ω planars as outrageously club-ready on bass and celebrators of the generally fulsome; a bit like our pre-Fazor Audeze LCD-2, albeit with clearly superior control and treble. Already owning a dual-XLR ALO leash for our Final Sonorous X, I tried that on the D8000/COS combo. Voilà, the tonal balance shifted up to suggest that a big part of the D8000's bass-head voicing came from the chunky wire harness. For Euforia's singular 6.3mm port, I reached into my Final grab bag and pulled out the original thin 3.5mm Sonorous X cable with adaptor. For the tubes, this retrieved far superior treble extension and speed. For the transistors, it had also equalized the potent bass to what I consider normal though brilliant. Knowing what these planars could do there, I'd call their bass via the Euforia and thin cable good but not 100% realized. Yet the D8000's stock 6.3mm cord plus Euforia conspired to something too bloomy and clotted-cream rich for my stomach. So the repatriated thin X cord became my default plug'n'play cable compensator. I fully appreciated that perfection would likely have come from a single-ended ALO leash like our balanced stretch but I didn't possess one.

The small crossfeed rocker lives right next to the power IEC on the right rear corner of the chassis.

Relevant to our Euforia discussion is only how these adjustments reflected on the respective qualities of the amp. Already rich, heavy, dense and bloomy headphones will get more so. Depending on taste and expectations, this could be just what's desired and ideal. Or it could overshoot and cross the line. If the latter, cable swaps might recalibrate ideal balance. If not, you could fancy an inherently leaner quicker possibly even somewhat bright can like Sennheiser's HD800.

For that model, our FAW all-copper Noir HP MkII replacement leash already addresses some common complaints of course. Still, there was no denying that Euforia's moisturizing appliqué felt awfully attractive on these Germans. Staging as wide and aerated as they're justly famous for, what the glow bottles shifted in my perception was the rise of each tone against silence. Rather than a tendency for a bit of hail on a tin roof or nails on glass sharpness, tones felt like tiny watercolour droplets hitting wet paper for just the right amount of blossoming not pin pricks. On the Sennheisers, crossfeed's minor fattening up of the midband and centre image didn't get overbearing either. This became a lovely tuning feature that was easily bypassed or engaged following along a playlist's mix of albums. Lean productions benefitted from a bit of fill, masterful productions sounded even better and wider without it.

It then was no surprise that the heavyweight Sonorous X would make for my most ideal Euforia partners. Materially damped with a shiny all-metal assembly, with a big 105dB efficient dynamic driver that's hard-coupled to the sealed enclosure, this costliest of the full-size Finals excels at punch, speed and bandwidth - perfect counterpoints which dovetailed watertight with the Polish amp's own virtues. As with the high-impedance HD800, 9:00 meant typical SPL yet the lazy taper left plenty of fine 'steps' up from mute. Even on overcooked fare like some of my beloved Middle-Eastern Pop which never comes out when anyone else listens, the upper mid/lower treble transition never sizzled. If the X's hard-kicking low end softened up just a tad too, that was simply par for this course. To maintain proper perspective, we now simply must step back from the close-up view whereby any A/B comparison magnifies small pimples into mole hills. After all, musical enjoyment doesn't constantly compare one's actual hardware against an imaginary other; or one concert hall to another. When we listen, we accept the sound as is. In that normal mode and as Lukasz Feliks claimed going in, their Euforia really is no overly tubey circuit. The glowing bits are far less about tonal balance or timbre shifts as they are about where the needle sits on the dry-to-wet continuum. If certain mega feedback high-power class D amps represent the dry-most polarity and a vintage zero feedback 2A3 SET the polar opposite, 'normal' in the middle with 15 clicks on either side, I'd locate Euforia some five or six clicks over toward the wet end - noticeable but far from extreme.

Because Euforia operated flawlessly quiet at the attenuator settings applicable to each particular load, the impact of the 'atmospheric conditioning' on raw resolution was relatively minor. Especially for natively crisp headphones—besides those already discussed, I'd include beyerdynamic's T1—the softer focus of the OTL valves should make for distinctly happier long-term sessions. And because that softer focus meant textural looseness that wasn't maximally taut like a shorted sail, images appeared somewhat bigger like a more swollen spinnaker perhaps. That combined with being centred in the midrange rather than approaching the tonal balance from the top down or bottom up added to an obviously big sound. That was all about not leaving this table hungry. Unlike certain transformer-coupled valve amps however which combine a similar largesse with ponderousness, Euforia never felt slow. I suspect that this was due to the OTL concept. It also meant more dynamic responsiveness. So no deep fireplace glow or rosy cheek syndrome. Euforia's harvesting of tube qualities restricted itself mostly to injecting a bit of what I've called echoic filler. Add fine workmanship, very clean looks, direct sales and a 3-year warranty. The currently best headfi amp from Feliks Audio cuts quite the figure. It reiterated my earlier observation that much impressive hifi these days comes out of Poland. Lepiej w to uwierz? You better believe it. As another reminder of Polish brilliance, perhaps cue up 2002's Upojenie by songstress Anna Maria Jopek, with guitar god Pat Metheny. Recall how that album title means 'rapture'...

Feliks Audio website