Early Koss Pro 4AA - How to date?

[Julie G.]

Hello! Is there any way to date a pair of Koss Pro 4AA headphones?

Mine are definelty an older version. The studs on the sides that have the older Koss Logo are bigger and taller than other Pro 4AA's that I have seen from the 70's. They also have a clear plastic casing on the cord where it attaches to the left side with a tiny black cover that is imprinted "Heyco" and "K-375-125."

Any help would be appreciated!

 

[Rey1]

Hello Julie G.

I have the same variation of the 4AA as you do, with the large "studs". I assume they are an earlier, older version of the 4AA as they have similar studs to the older Pro 4A. By the way, mine sound absolutely fantastic. How does your set sound?

 

[Rey1]

bump!

So does anyone else here have a set of Pro4AAs that have the large studs? Did anyone purchase them new? If so, when.