First off, any change, gear or even a tube change on the same piece, makes for a different sound. No matter what you do, your "magic" will have to be recreated, whether with the tubes provided or after rolling, and even then is always somewhat different than the last time (shades of magic, so to speak).
About the LTA pre, I haven't heard it but in the process of deciding what to go for I asked its developer (Mark) and those on an LTA thread, I think on head-fi, about where it stood on the warm to cool continuum. The unanimous answer was decidedly "neutral." Since I favor some warmth and don't get along big time with what passes for neutral -- it sounds cool to cold to me, -- the owners and those familiar with the LTA explicitly steered me away. For Supratek, what caught my attention on the site was that Mick prefers and designs for some degree warmth. An email exchange confirmed that.
About the LTA pre, I haven't heard it but in the process of deciding what to go for I asked its developer (Mark) and those on an LTA thread, I think on head-fi, about where it stood on the warm to cool continuum. The unanimous answer was decidedly "neutral." Since I favor some warmth and don't get along big time with what passes for neutral -- it sounds cool to cold to me, -- the owners and those familiar with the LTA explicitly steered me away. For Supratek, what caught my attention on the site was that Mick prefers and designs for some degree warmth. An email exchange confirmed that.