6SN7 suffixes

I'm using 6SN7's in my Atma-sphere equipment. I was curios about the multitude of letter suffixes that follow the 6SN7 tube type.
Check out www.tubeseller.com. Everything you need to know about 6SN7 tubes is there. Brimar CV1988 tubes are especially nice, and one of my faves.
Fatparrot, I was waiting for more experienced users of the tube to chime in first, but since no one has yet, I'll post.

Did you want to know what the actual GT, GTA, GTB, W, VT-231 designations mean or were you more interested in their sonic characteristics?

I've been rolling different 6SN7s in my Blue Circle preamp for over three years. I don't actually know what any of the suffixes stand for, but I have learned some of the tonal differences and which ones I like more than others.

I've found that the different manufacturings such as Sylvania, RCA, Raytheon, Ken-Rad, Tung-Sol, etc... all have their own distinct flavors as well.
Please share your insights regarding 6SN7 flavors.
Gunbei, I was more interested in the designation of GT, GTA, GTB, W, and VT-231, and what they actually mean. I am pretty happy with the voicing of the Sylvania VT-231's in my system.

What have been your experiences rolling the various 6SN7's? Why does everyone seem to rave about the Sylvania metal bases or the Sylvania "chrome domes"?
I really like the Sylvania VT-231s as well. I don't know anything about the differences between the metal base or chrome dome versions though.

One tube I've really enjoyed the last few years is the black glass Ken-Rad VT-231. Many of the same attributes as the Sylvania, big soundstage and great extension, but the Ken-Rad sounds more organic to me and that was something I was looking for in my system.

Thanks for the pointer Nutella!
You can also go over to vintagetubservices.com and make your way to the stock list page, then click on octal tubes.

If you read your way down thru the selections and brands,
you will also get a minor description and history of the
differant types.

A proper answer to your question would require a short term
paper on 6SN7's as it would cover the history, require-ments, uses, tooling changes, etc... thru the years. But
Andy puts in some helpfull, and interesting tidbits in the
price list that may help you out.
Fatparrot, when I first got into the 6SN7s I did exactly what Charliee is suggesting. Andy has breakdowns of all the tubes he carries with some nice brief descriptions.
Early 6SN7 had metal cases. the GT means "Glass Tube".
Thanks all! Charliee, I use Andy at Vintage Tube Services, as I feel that he is the "go to guy" for all things tubes. I usually speak to him over the phone, so I hadn't been to his website since I switched to a high speed cable modem. Loading with my previous molasses slow modem speed and ancient computer, it could take awhile to download.

Yeah, there's some good stuff there. Here's a link, so others can see why those want tubes go to Andy:
Stock List

Just in case you find navigating his website a tremendous pain in the ass, as I do. But he does have some great info!