Figure I'd start a thread here with some early impressions, since Danny is finally sending out review samples for these. The short of it is that other than some questionable stuff coming out from China, these are the first aluminum ribbon driver headphones. Because the internal resistance of the aluminum band is so low and because the product is essentially a pair of tweeters being press ganged into full frequency range duty, they require an external 4 ohm adapter box for tuning and protection of the amplifier. The box makes these things incredibly hard to drive - think 50 watts/4 ohms per channel at a minimum, and 125w+ as a good target to hit. They will actually draw 50 watts on peaks if you like higher listening volumes, so tube amps outside of a few select designs (KT88's, KT150's, strong 845's?) simply won't be able to feed them properly. That said, if you can drive them off tubes the pairing works like a charm. The headphones themselves are light and comfortable. Extensive use of carbon fiber means that the drivers have better weight distribution than they look. Fit is K1000-style with two foam pads and a soft overhead leather band to spread the weight around. I can wear these for hours with zero fatigue which really can't be said for the LCD-4 or the Abyss 1266's. The cable is detachable with dual 3.5mm connectors and actually accounts for most of the load from the adapter box output: more than 90% of the 0.2 ohm load is from the cable and not the ribbon. One would think that ribbon drivers can't deliver proper bass but surprisingly, bass is not an issue at all. It's punchy and well-defined, very much on par with the 1266 phi's, a little lean compared to something like the LCD-4. Treble is definitely the strongest point on the SR1A with incredible speed, clarity and massive dynamics. The speed is almost a revelation of how slow "normal" headphones are in terms of rapid transitions. I'd go as far to say that the treble delivery on these with the Nagra INT is a meaningful step up from the likes of the 009/BHSE combo or even the HE90. It's that good. Midrange isn't quite recessed per se but I feel that it's a relative weak point of the Raal's. The SR1A's midrange has enough resolution but the overall structure is a little soft, especially when you compare these to a reference-level midrange such as that of the Mysphere 3.2's. Vocals aren't intimate in the way that the Utopia or LCD4's are; the lightning fast transition speed is somewhat of a detriment in that regard. That said, I had no issues enjoying vocal-heavy tracks, and the spaciousness of the open design leads to an almost "live house" feel that I can get behind. So far I've tried them with a couple of integrated and power amps, and my favorite combo is probably a tie between the Audio Research REF75 and my Nagra Classic INT. Amps with midrange emphasis helps with overall coherence as do amps with a bit of treble rolloff. The more neutral Simaudio power amps felt slightly too polite with the Raal's, and Spectral's house sounds delivers a bit too much energy into the treble range. My impression now is that people are going to have a love-hate relationship with these not unlike that of Spectral. A lot of it comes down to how much treble energy one feels comfortable with and preferences between the free-floating bass signature of ear-mounted speakers and the larger bass quantity of high-end planars. That and actually owning an amp that's powerful enough to drive them.