Valhalla is a Class A, single-ended triode headphone amplifier with no overall feedback and noninverting circuit topology. It provides classic tube sound and can drive headphones with impedances as low as 32 ohms.
Yes, we know that all you got out of the preceding paragraph is probably, “Classic tube sound.” And if you’re not a tube junkie, you might not even know what that means. Some people say tube sound is a smoky nightclub with a hot chick in a red dress, it’s a warm swimming pool in summer, glowing green against the purple twilight, it’s a . . . well, hell, you can’t really explain tube sound. Think “smooth, fluid, liquid, alive.” But not in a SF-movie-gonna-eat-you kinda way.