Shootout of Nos 6sn7 tubes

Couple thoughts:
1. I *really* think you need to include shuguang WE6SN7 plus and CV181-TII in the group you audition. However,  these will require some period of break-in. So that might slow down your testing and comparisons. 
Many folks who have rolled all the tubes you are testing have come to the conclusion that these new production tubes are right up there with the best of the old best NOS tubes. 
2. Do you think you need to be concerned with burn in when you are testing these tubes?
3. There are several great 6SN7 threads out there.  Please add your comments to these threads on head-fi and here on Audiogon.  Look for 6SN7 reference and 6SN7 tube addicts threads. 
Keep it up. 

Although I have Shuaguang Black 181z, it is not Nos, it will not be included here since it is not Nos.

I had already done comparison between Sylvania vt231,and Shuaguang Black 181z about one year ago.

My conclusion is that although latter sound warm and organic, it falls short of the former in details and transparency.

Thus it is not in the same league as five vt231 tubes here.

But its performance will be close to 6s7ngtb made in 1950’s which can be bought at 50-60$ per pair.


Some pre amplifier makers recommend new production tubes.

The reason is simple

They can get hundreds of new production tubes but not hundreds of Nos tube.

Thus they can not design their amp based upon Nos tubes.

I am not going to expand my inventory more than 14 kind of tubes that I already have.

This is subjective test for fun.

Choice of tube is dependent on personal taste and system.

Thus people should try themselves in their system.

@markusthenaimnut-   "Do you think you need to be concerned with burn in when you are testing these tubes?"                Like virtually everything else, in this hobby, people will argue, forever, about that.     My experience parallels that of Brent Jessee, who’s considered (by many) an expert, regarding NOS valves.     Here’s a verbatim excerpt, from an instruction/info sheet, he included with my tube purchase:    "New tubes need a break in period before they can exhibit their true sonic character when used in audio circuits.    Preamp tubes especially benefit from a good break-in.    This period may vary widely, but NOS vintage tubes usually need at least 48 hours of use, sometimes up to 100 hours.     New current production tubes need 24-48 hours typically."

Rodman-
That makes sense and matches my own experience. I brought it up on this thread because it might be a factor in the listening tests of the shootout. 

I agree with markus and Rodman.
True NOS NIB will need a breakin period. Vintage tube "pulls" that test as NOS will also need some breakin time.