audiogon suspended my account so had to create a new one
i have tried other 6sn7 tubes and some like you say were to bright sounding, so didnt care for those.....i think those were the rca's ( could be wrong ). i have tried the sylvanias also and like those as they are a bit more laid back.
if you’ve not already tried possibly more transparent interconnects (yes it can help) to try on loan, between your sure and preamp, and preamp to amp 3) then if still not resolved, ask your PBN speaker manufacturer if there is a more open crossover capacitor or slight crossover/x-over change to open up that tweeter a bit more, is it rolled off some?
i have tried other IC's and it changed things, but not enough.
there is nothing wrong with the speaker, i dont need to have the tweeter opened up more, there is plenty of detail.