I've been advised in the past to look at the Belles 28A Ref pre-amp. I have not had a chance to do so therefore, I cannot describe what I've heard. There are many good threads on pre-amps floating around on Audiogon from which you can glean much useful info. Look back on my system thread discussions as well as at this thread among others;
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1222917424&openmine&zzZephyr24069&4&5#Zephyr24069
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1222917424&openmine&zzZephyr24069&4&5#Zephyr24069