Older vintage 30's vs newer

[jonahstepro]

I have an old Mesa Boogie cab that has Vintage 30's in it. I have heard that at some point Vintage 30's changed and the older ones are worth more. I wanted to see if that is true at all and if so at what point did they change.

 

[Hacksaw]

Here is a really good V30 reference.
https://www.thegearpage.net/board/index.php?threads/851486

I don't know about worth more, some of the older ones sure sound better.

 

[smolder]

I don't know anything about any manufacture change, but break in takes forever and makes a huge difference with these.