Best 6SN7 Pre Amp tubes?

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.

Hey Tube Gurus, your opinion please.

This is a bit off topic, but close enough, I think.

My VAC Phi 200 amp uses 6NS7GTs for the voltage amplifier/phase splitter, and drivers. The power tubes are KT88 and I just rolled the new Gold Lion KT88 reissue (BTW, Wow!).

So my question is, since these stages are less critical, is it worth it to replace all my 6SN7s with BT or Psavane 6SN7s? Does anyone have experience with how it might benefit the sound of the amp?

Of special interest is if anyone is running BTs, Psavanes, or any other high-end 6NS7s in the low level stages of their amps... especially (dare I dream?) if you're also running Gold Lion KT88s for power and even more especially (somebody stop me), if you've got a VAC Phi 200!

I await your tubey wisdom.
Cheers!

The Gold Lion KT88 is a great tube. But to answer your question... yes. You will hear an improvement with the BT CV-181, even in the lesser stages of the VAC amp. You will be surprized at the difference you'll hear in the low level stages.