Best 6SN7 Pre Amp tubes?

I have the Tung Sol Blackplate that Teajay is talking about. It is a very good tube.
But the OP didn't ask about the Tung Sol, and it didn't take me off the quest for 6SN7's. The BT did.

09-05-11: Tpreaves
"Best" is in the eye/ear of the beholder. There is no definitive "best" anything, it's all subjective. When you ask a question like this, the answers will always be what folks think is "best" to them in their system.

Disregard, I posted this to the wrong thread. My apologies to the OP.

Are the Sophias and the Black Treasures made by the same factory but sold under different labels? I have a pair of Sophias for my ModWright Sony SCD-XA5400ES and have thought about trying the Black Treasures but they appear to be the same tube. If these tubes are made by the same factory how do they differ?

They are not the same tubes. Or the same factory.
Completely different in every way. The BT is a much larger tube than the Sophia.

Zmanastronomy is correct.

Black Treasure is produced by Shuguang, Sophia are relabeled Tianjin/TJ. I'm not sure if Sophia performs any additional verification or procedures on these tubes.

In speaking to Shuguang, they have repeatedly told me there are no potential benefits in terms of measurements, sonics, reliability, or longevity of Grade A/Premium over the "standard" tubes, as both are culled from the same production lots, with no prior knowledge as to what tubes should slot where. You are simply paying for different measurement procedures and packaging.

My own evaluations via testing, listening, etc. confirms the statement regarding sonics, though it's still too early for me to comment conclusively on medium - long term reliability and longevity.

From what I seen thus far, this "grade inflation" does not justify paying more for tubes.