Question for tube aficionados

I recently upgrade my Cary 120 with new Gold Lion KT-88's and Psvane 6sn7.
Previously I had Gold Lions, but they had quite a few hours on them. I also had Tunsol 6sn7's
The Psvane Grey bottle are a matched Quad and the Gold Lions are a matched octet.
I'm constantly blown away by the increase in soundstage and detail, both high and low.
Psvane makes both a 12au7 and 12ax7.

I will be upgrading my Cary SL98P F1 from the Tunsol 6sn7 to a Psvane grey bottle matched quad.
I like the Psvance, that much.

The difference in sound between NOS and new production tubes is slight and you will spend a lot of money finding NOS tubes that are (1) not fake, (2) not microphonic (3) not noisy. My 2c worth. I gave up the chase years ago and now use matched and tested JJ or Sovtek tubes.

Also, CJ amps of this vintage typically use circuit designs that are not optimal to produce a "tubey" sound. They are also prone to oscillation with the wrong tube choices because of CJ's refusal to follow good design practice and use grid stopper resistors. The difference NOS tubes will make is like cables - not much. I'd stick with what works.

"The difference NOS tubes will make is like cables - not much."

Interesting analogy except with cables you can show them off, not so much with many tube designs, particularly preamps. Just like anything else in audio, the depth of one's pocket is the only limiting factor.

Hello, I’ve owned the PV-11 for over 20yrs now. It was my main preamp for 10yrs but I have moved onto a AR SP-11 Mk 2. I still have the PV-11 in my collection of preamps. The tubes that sounded the best to me in the PV-11’s linestage is the Amperex 7316. I think other Bugle Boy 12AU7’s may sound good also but the 7316’s were the most musical and revealing tube for me. Keep in mine that the linestage of the PV-11 is fine but it’s phonostage is totally awesome. 

I'd agree that not all NOS tubes are genuinely "new" old stock and a reputable dealer is worth seeking out.  
Not every NOS tube is by default always better than current production,  it depends on numerous variables.  I can vouch for the upper level of the Psvane tubes for example. 

Based on my experience I believe that you can find high quality NOS tubes if using a honest dealer/vender.
Charles