To that end, I have found the Darkvoice 336se to be by far the best of the four headphone amps that I have owned thus far. While I prefer the tube sound, the small, little bitty amps with tubes sticking out do no create and expectation of good sound. The 336 does not fall into that category. Looking at it you just expect good things.
It is a shame that the manufacturer has not produced a website. I would like to get in touch with a manual, but such an animal does not seem to exist.
I am also a tweaker and at times find myself using the music to listen to the equipment and not vice versa. I know this will not be my last amp. The Bottlehead Crack seem to be a good next move. However, I do strongly recommend the Darkvoice. It is one heck of an amp.
Enjoy the music and the equipment, JS