I have a pair of JBL 4612Bs and two pairs of 4612OKs. After more than 30 years of service, I thought it was time to replace the crossover caps. From looking at the crossover schematics, I have some questions. JBL changed the crossover cap value from the original 4612 from 3.0 down to 2.5 on the 4612B. Any thoughts on why JBL did that and what change did it make to the crossover frequency?

On the 4612OK, the cap is 2.5 but has the addition of a .01 bypass cap. Why did they feel the need of the bypass cap on the OK version and would the 4612B benefit from a bypass cap?

Finally, is it safe to assume all the inductors are still OK or do they need to tested and possibly replaced?