AFAIK,NB's didn't come out until late 60's..........I bought my first pair,brand new, in around 1970.Blair
As the ad headline stated, these are pre-New Beat hats - both top and bottom of similar weight.
I have a pair of these and they are great for Jazz and lower volume situations.
The New Beat configuration used a thin top and heavier bottom cymbal. The 14's from the '60s that
I've owned are generally 750-800 grams top and 1150-1250 grams bottom. They are great versatile
cymbals.
Zildjian endorser Louie Bellson started using the 'New Beat' configuration in the mid '60s and Zildjian
started selling the heavier 'New Beat' bottom cymbal individually around 1967. The New Beat set (thin
top & medium bottom) was offered later but I don't recall exactly when.
The New Beats over the years have gotten heavier and louder, with a different profile. They're still
versatile cymbals but nothing like the 60s NBs.
As an aside, the newer Armand A hats are very similar to the '60s in both weight and profile, although
the lathing is different.