A triodes do not blur instruments to this degree, and do not reproduce action in quite the same way. When it comes to soundstaging, the Atma-Spheres take second place to none. That's how focused the Atma-Spheres are. The MA-2 Mk. IIs don't merely bring superior focus to the soundstage.
Instrumental harmonics are also in better focus.
For instance, the upper register harmonics of female vocals, particularly when the singer is singing forte, are typically exaggerated by pentode and solid-state amps. As long as we're talking about harmonics, let me say a word about the Atma-Sphere's tonal balance. That word is, gorgeous. This thing is as flattering to instruments as any amp I've heard, single-digit triodes not excepted. IIs are rather to the darker side of dead-central neutral, in part because they are a bit more recessed in the midrange and upper midrange, and a bit fuller in the bass.