The DV336i matches well with the DT880/600. A modicum of all-tube warmth, but with a punchy dynamic. My guess, based on my experience with the DV337 and the DT880/2003, is that the DV337 would suit the DT880/600 well, too, although overall I found the DV337 less musically engaging than the DV336. : )
I enjoy the DT880/600 best driven by the Bada PH-12 that Fitz upgraded for me.