Tubeyist sounding Pre-amp?

Aesthetix.

Maybe try a Yaquin tube buffer between your amp and pre.  $200 at Amazon.com of all places.  I hear these things work. 

@Randy- Did you read my previous post? It will cost much less than $500, to experiment with your Sonic Frontiers pre and British tubes. Just add two matched, LOW NOISE tubes in each gain stage, until you obtain the presentation you prefer. Amperex tubes will also add some warmth, though not as much as the Brits. These recommendations come from over three decades(going on four) of tube rolling, in a very wide variety of components/systems.

@Randy-  Here's a bit of info that may be of interest to you.   Read the section, toward the end, that's headed, " MULLARD, GENALEX, BRIMAR, and other British made NOS".  (http://www.audiotubes.com/6dj8.htm)

Thx - my pre-amp is broken and may not be worth repairing