6SN7 variants circa 2019 - tone, longevity, reliability, value

@markusthenaimnut  GE, RCA, Sylvania. Bad Boy.

Thanks for those additional brush Strokes in your picture. Helps to provide some context for your recommendation.

@markusthenaimnut I think you already know, but to mark it in the appropriate thread, I've tried the Shuguang WE6SN7 PLUS and Black Treasure C-181Ts that came with my Don Sach's Pre.  I thought the WE+ was a bit brighter/thinner and preferred the C-181Ts.  They seemed to have better body/weight in my system.  In the end I did switch to RCA grey glass (buffer tubes) & and Rayteon JAN-CRP-6SN7GTs (driver tubes).  They provided a smoother sound with better layering.  I can imagine that what you end up preferring is highly system dependent...

Guys - thanks for all the info you are sharing. I think this thread is very useful, because many of the other discussions regarding 6SN7 tubes out on the web trace their origin back 10 or 15 years, and many of the vintage tubes preferred are now extremely expensive. 

Also, at that time there were far fewer Chinese variants on the market.

FWIW, I'm currently using a pair of Russian 6H8Cs from the Novosibirsk factory. I'd describe them as very balanced throughout the spectrum. I'd describe them as neutral and transparent. I've been burning them in for a couple of months now and I think they sound very good. They replaced (not because I expect them to be better, but simply because I am curious) a pair of black glass Ken-Rad VT-231s. 

I'm hoping this thread will provide a handy reference and place to share experience with this wonderful tube variant.  

It is an interesting thread, I think most of the tubes used and the sound will depend on the amplifier or pre amplifier these are used. I own an atmasphere MA-1 monoblocks and MP-3 pre amp.

Let me start saying that the amp and preamp comes stock with shuguangs red base clear glass 6SN7s and the sound is very balanced, rolling tubes can indeed provide better sound to your liking but I find myself using the stock tubes as a reference a lot, these amps and pre sound in credibly good with stock, now that said.
On my preamp I am currently using Chinese shuguangs BT CV-181s very balanced sounding and silent tube, I tried Sylvania GT, GTA and GTB, the sound changes and IMO it has some glare, actually I believe the correct word is sibilance (the sssssss on vocals). Tried the Psvane tube and the sound is similar to the shuguangs BT but one tube died after 20 hours of use and I have only one now. Many will differ with me but I have tried and own the rca red base 5962 which everyone loves and I have find it not very special. The best sounding tubes on my preamp are the GTs, I have the Raytheon black glass GTs and love the sound, that is the only tube I prefer over the BTs on my preamp.

Now onto the amps I have tried several, in this case the Sylvanias are very good sounding, the front tube in my case must be a GTA or GTB because of the voltage, that is my understanding but overall I think the GTs are the best sounding tubes assuming of course equal quality, if you have an old GT chances of microphony could be higher than a more recent production GTA or GTB YMMV
I tried the 6H8C metal base military spec (3 separate pairs) and they run very hot and are prone to failure, 2 died on me and one is microphonic after use so these in my specific case are a no no, the sound I found it to be not as full as with other tubes but I'm sure this is because of my specific equipment. BTW from the beginning Ralph told me Russian 6SN7 on his amps will consistently fail so I was warned early.

No intend to drive this thread into an amp discussion but it is kind of important as discussing tubes alone without the equipment in which these are used has no real meaning. Current and voltage and type of circuits of these amps and pre amps makes all the difference.