You're probably already aware of this site:

https://www.tubeworld.com/6sn7.htm

I have not heard these, but, they won't break the bank and might be something you could experiment with:

http://triodestore.com/tubad.html

You might do a search over at diyaudio and ask the guys over there:

http://www.diyaudio.com/

They've got a lot of collective experience.

Go to a 12SN7, by altering the heater circuit.

That way you will have a BA-JILLION of the best tubes in the world to select from, with no 'audiophile' pricing to get in your way.

An example of audiophile pricing:

I have a MFA "Venusian" preamp, a 3 chassis(!) Octal tube preamp. In the phono section, there are 4 RCA red base 6SN7's, all measuring 85/85, 85/85, 85/85, 85/85. I could likely get about $1200-1500 for them. But they're not for sale. I need them!

If I flipped the heaters around to use 12SN7 instead, I could use many different tubes......and not $300 each, either. More like $15 each, on a bad day. And they are no worse in sonic quality than the Red base RCA's.

If anyone wants to take a look at The MFA preamp, one of the most stunning pieces of kit ever made, and a landmark piece of gear...detailed high res images are on the DIYAudio site. Do a Moore/MFA search, and get into the only 'Lumi' preamp thread.

How-Now-Brown,
I've had excellent results with the 6N8P which is the Chinese Militiary version of the 6SN7. It's very well built, way beyond spec, with excellent sound and very low noise. These should have a long life. I've never had a tube failure with ones of these. One of the quietest tubes I've ever heard. The are very affordable. I paid $40 for a quad of them NIB. That's my two cents, but I'm sure others might have better suggestions.
BB

I'm discovering this is all very system dependant as well as personal preferance, this subject is also full of pretentious thought based on rarity, value, geography, good and bad years and even NOS vs New stock. However these are a few of the ones I've tried and their overall impression what they're good for as well as a negative.

I also will suggest the chinese 6n8p if you prefere accuracy and realism, good for livening up a dull system. Can get harsh.

Smooth and clear try the CBS 6sn7gtb great extension on both ends. Can be soft.

rich and harmonic try the RCA 6sn7gt bottom getter great all rounder. It can sound too sweet

Details and compression with good tone Tung-sol 6sn7gtb. Can add girth to your tone. Can have too much detail.

Big bass really nice top Sylvania 6sn7gta Chrome dome. Good for adding bass. Can have too much bass and narrow mids.

Lots of treble and Clear mids GE 6sn7gtb side getter. Too much sybalance Ultra clear mids can sound thin.

6SX7=6SN7

6SX7 blows them all out of the water. Whoo-hoo!

Good luck finding any.

Isn't the 6SX7 just a mil labeled 6SN7?

If not, what physically is different that makes it sound better?

Super low noise, JAN, Medical, Testing, Research-design, super select.

Not much other than that, IIRC. Basically, someone has cherry picked them to be the best one out of about 1000-10k tubes, or so. Which I'd gladly pay say, and extra $5 for.

Basically, if you are susceptible to 'getting wood' over an octal based preamp tube, this would be the appropriate item to fawn over.

I believe there may be constructional differences, but I'm not that well versed..yet. I'm only at the 33'rd degree of the glow(b)inatti cult. I'm not privvy to the super secret information. I'm already going to be in trouble from the rest of the cult, for spilling insider information out to the 'useless tube eaters' out there.

And I'd swear that the Google search engine is 'following me around',as that's gotta be the 10th time or so that I make a post..and it shows up in Google within 2-10 minutes or less. I went searching for 6SX7 info, and this post was at the top of the heap. Not more than 2 minutes after making it.

Makes sense.

I remember learning at some point that they were the same tube, but there are plenty of mil tubes that were cherry picked. It's often worth the extra money to get the pick of the litter.

Pretty amazing that Google reacted that quickly.

As for Google, there is a potential reason for that. One that I won't go into here.

One, is that the main Google offices use Goo Systems Screen Goo, one of my companies (part owner). It is only correct that Google have Goo Screens, is it not?

There are other reasons.

Please let it be black helicopters!!!!!

Can you get me a ride?

Yes I can. All I have to do is go outside and give them the finger. They'll be waiting. Although..it'll be hard to enjoy the ride and see the scenery when we're handcuffed to the floor.*

*(Note to the humour impared: This is very dry humour. As for spelling humour, in the Queen's English, the only proper english...humour has a 'U' in it. The queen explained it to me. She's the one flying the helicopter.)

My information says she was the third shooter on the grassy knoll.

I am enjoying the image of the Queen at the controls of a helicopter, replete with a tiara equipped helmet.

All in black leather and black body armour, of course.

Same outfit she wore in Dallas.

The 6SX7 is not a registered type.

I saw that post on another forum also. I have no way of evaluating whether the writer is correct or not.

LOL!!!!!!

Thank you, Jeff!

Love it Jeff! I just wonder where on earth you ever found time to do it. Fancy 'borrowing' my kids for a week?

...or longer...

OK. The internet term LOL applies on that one. Great Jeff!

I'm glad you guys got a kick out of it. Sometimes having fun is more important than doing work--speaking of which, time to get back to that.

That's a JAN VT-231 'bad boy' style smooth-plate tall-bottle 6SN7. Sylvania? Pre-war? (40's)

They are Sylvania tubes.

I made an simple tube pre with 6sn7, the sound is very good, the schematics is very simple. I used two 6SN7 dual-triode, NOS made in CCCP :D

You can see more pictures wih this tube pre on website: http://www.apcc.tk/photo-gallery/category/21-tube-pre