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

NOS GE 6SN7GTBs are a great tube and I use 5 of 'em...4 in my preamp and 1 in my single ended little tube power amp...I like the Sylvania "chrome domes" also, and Amperex although they're hard to find.

I have not tried the CV 181 tubes.

To respond to the earlier mention of current-production Tung-sol's reliability - we used to use all Tung-sol for manufacturing and might have had one 6SN7 failure, though it could have been caused by something else. That is through hundreds of tubes. Admittedly, the amp topology (microZOTL) is quite different from Atma-Sphere. 

I am interested in anyone's experience with the newish JJ 6SN7.

@markusthenaimnut

...I’m interested in hearing your thoughts about *Tone*, reliability and value. I’ve been trying to get a handle on the Shuguang & Psvane tubes. Many folks rave about them sounding better than virtually all the famous NOS tubes. ...
...
Excellent point about *where* the 6SN7 is installed and its intended function....I’m using the 6SN7s in my Supratek Cortese preamp.

markusthenaimnut, for what it’s worth -

You’ll find countless forum threads on various sites dating back to early to mid 2000s when good NOS 6SN7s were more readily available, more affordable. And, more recent debates the past ten plus years on various rebranded Chinese, Czhec, and Russian tubes. After trying some unobtanium quads of 6SN7 NOS, a few different re-issues, and some higher end boutique Chinese stuff made for resellers..., I concluded something for my system. It really comes down to what "tone" and presentation you prefer for your ears. AND, what adds further variability to the mix is "your system", your amp(s), your speakers/sound/effciency, your cables, caps in your gear ...and so many variables that shape the final tone and presentation. Sounds stage is a whole other deal I’ll stop here on. The more you’ll read the more confusing it gets and particularly with preamp tubes. I finally gave up reading others posts and just started trying them to find out first hand. Again, it all came down to my system, and when someone says it’s truly "system dependent", it’s true or it was in my case too.

In general terms, most of the re-issues typically don’t have the same type of presentation or sound stage depth as NOS, many for me were a tad more forward and not as textured, yet that might be a good thing for your system. I recently pulled and hoarded away my quad+2 of NOS Sylvania 6SN7GTs from the 1950s that I loved. Went back and re-tried new TS, EH re-issues, and then started messing with boutique Chinese tubes that are getting better, and still in my preamp now after a few months. A few buddies and I figured out the part of the "reliability"or "longevity" situation ALSO has to do with packing, packaging, and shipping from overseas and China too. Some of the larger distributors figured this out with dead-on-arrival failures and SOME pack and package better now. Whatever you do, take others advice and IF you buy NOS, "get them from a reputable dealer" with good testing tools and processes, and the same really applies to online purchases of new re-issue tubes.

What about the current sound (with your system) is it that you don’t like, what do you hope to change by replacing tubes in your preamp?

The Shugauang WE plus easily bested the NOS 6sn7 I purchased from Andy (VTS) and the NOS 12sn7 shipped with my microzotl. I can’t speak to the long term reliability as they were installed this summer. It’s my understanding if they don’t fail within the first 100 days, that’s a pretty good sign. As to the sound, they provide an expansive and better layered soundstage than the NOS.