There's a fine balance I think.

I like a little bit of euphony in my headphone amps. The ZDSE for instance has a little bit of sweetness, but it's still more transparent sounding than a lot of other amps. On the whole Cavalli amps tend to strike the perfect balance for me personally; it sounds pretty cliche I guess, but they just have this effortless musical quality. It's like the idea that sometimes what sounds better isn't what necessarily measures better. Measurements are really important, and there's generally a correlation between measuring better and sounding better, but sometimes I think amps with really good numbers sound too tight-assed (to borrow dBel's descriptor) or musically necrotized.

But yeah, balance. Too much "euphony" is pretty atrocious to my ears. In that sense the Leben CS-300XS was just way too much. Like drowning in maple syrup. Hell, you could half it and it would still be too much. Same w/ the Woo amps I've tried. The WA22 was actually worse than the Leben with a lot of tubes I tried.

I think some people gravitate toward these really warm and blurry amps because they have headphones that are overly bright or gritty, and it's a way of masking that. There's also this audiophile association with tube amps as a whole fitting this bill, because certain publications and well known head-fiers publicize their way of listening, calling it more musical or whatever. Which is inducing because tubes are actually extremely linear, and it's the amp that is producing that mushy sound.