Best 6SN7 Pre Amp tubes?

The BT are a more open and tonaly ballanced tube in my system than the Sophia's. But, the Sophia's are close.
I've tried every NOS tube on the market and finnaly settled on the Sophia. Then I tried the BT and my quest was over.
Do not buy the BT from Ebay. The ones from Grant Fidelity had much better tone and was much quieter.
I have no affiliation with Grant Fidelity other than a happy customer.

I did "almost" the same thing as Zman. I started with the Black Treasures, then when to the Sophias in my LS100.

Had I started with the Sophias, I probably would have stopped looking, but I also really like the BT alittle more.

I bought my BT's, (and some Psvane for the phono stage) from Grant Fidelity. Excellent company to work with.

I tried alot of different 6SN7's too.

My answer may be partially relevant. I have BT and Kenrad black tubes. The BT is more open and Kenrad is smoother.