I have to agree with TWL. The Berning Siegfried, after 12+ yrs in this hobby, has blown me away to a place I thought I was too jaded to experience anymore. (I'm using the 300b model, w/ Avantgarde Duos). I haven't heard Atma Sphere gear, or even the 270, for that matter. All I wonder is why the Siegfried remains such a secret. It's a technical and sonic masterpiece. It has all the finesse and intimacy of any tubed gear I've ever heard, with none of the coloration or euphony, and much higher musical resolution. And the bass slam, authority and control of a SS rig. How insane is that?