head over to http://www.alessandro-products.com/vacuum.html and they give a run down on tubes they like.  i'm sure that the guys at allesandro have tried many more tubes than any of us around here, and so i think they're opinion should be valued.    They seem to like sovtech. the only sovtech product i've played is a Big Muff that was pretty amazing. I'll be buying sovtech tubes for the lightning i'm about to build