You mentioned about a very long break in time, several hundreds of hours.
Do you mean something like 600 ? 700 ? or around 300 ? and the 6550tube last only
2000 hours according to user manual. 1/4 of its life will be used to break in the units.
My Ref 40 Ann. has passed its 140 hours. But still not bloom and deep bass still lacking
in weight and body. Only upper mid and high that seems to open up.
I've heard better from my last Ref 5. But My Ref 5 had 600 hours on it when I got it.