[dminches]

Quote:

I've read statements along those lines before, but what is the alternative?

 
There is none.  People should just take the readings with a grain of salt.  And, as Stavros said, visually inspect the tubes.

 

[Skylab]

I agree Rob.
I would add the 6SN7W, which is one my all time favourites and one of my reference 6SN7's.

Absolutely ! One of my favorites as well.

 

[dminches]

They have also gotten ridiculously expensive.  They cost close to what TS BGRPs sell for.

 

[nututubes]

Quote:

Absolutely ! One of my favorites as well.

 
Quote:

They have also gotten ridiculously expensive.  They cost close to what TS BGRPs sell for.

 
I already have one pair, and yes they are wonderful but expensive.
But for those who might still want some....http://www.ebay.com/itm/SYLVANIA-6SN7W-METAL-MATCHED-PAIR-NOS-/130739607874

 

[Audio-Omega]

I suspect the tall Sylvania I had was taller than Tung Sol 6SN7GTB.  It would be taller than those in your photo.  

 

[Xcalibur255]

Quote:

They have also gotten ridiculously expensive.  They cost close to what TS BGRPs sell for.

Supposedly they are prone to arcing over and going up in smoke too prematurely.  An interesting trait for a tube that was meant for military duty.

 

[rosgr63]

I was actually referring to the non metal Sylvania 6SN7W's.
I have the metal version as well but my reference tube is the short bottle with the lower mica inside the base.
They metal base ones suffer from cracks, be careful when you buy them. 
 
The final and best test as Bob Putnak has taught me is in circuit.

 

[Xcalibur255]

The short bottle W with the extra support rod and the lime green base lettering?  I've had several people tell me this is their favorite Sylvania but I wasn't ever wowed by my pair.  Really need to get myself a tube tester one of these days........

 

[rosgr63]

Yes, that's the one.
 
I have a selection of them, but I have noticed differences in sound from different batches.
 
I am repeating myself here but a calibrated tester is the best tube money ever spent.
 
EDIT: System synergy is another factor, your tubes could be fine.

 

[Silent One]

Last year, I tried really hard to save for a calibrated tube tester. And I successfully did. Twice. And twice, opportunity costs reared its head. 

 

[dminches]

Quote:

I was actually referring to the non metal Sylvania 6SN7W's.
I have the metal version as well but my reference tube is the short bottle with the lower mica inside the base.
They metal base ones suffer from cracks, be careful when you buy them. 
 
The final and best test as Bob Putnak has taught me is in circuit.

 
Can you show us pictures of some?

 

[mrAdrian]

Two more tubes that I want to show/ask as of today.
 
The first one is a weird mix between 'MADE IN USA', 2 stars, un-branded (or it might have came off), and has CV1988 written on the back of it too. Maybe it is a US/UK ally witness tube?
 

 

 
 
The second tube is a GE JAN tube made in CANADA. I thought all of them are US made? Would it be a worse tube if its used in the Canadian army instead? (Not to be offending anyone - just always thought GE was US based)
 

EDIT: and the GE tube is what you call a tower plate structure?

 

[Skylab]

Both the short bottle AND the tall bottle Sylvania 6SN7W with black base are excellent tubes.

 

[rosgr63]

Here they are David.
 
 

 

[dminches]

Very nice - thanks.  I think I only have the tall bottle variety.