There's a thread showing the crossover schematics at Classic Speaker Pages (CSP) and
from what I remember one has double pole level control switches and the other single.
I think the B version had single pole:
https://community.classicspeakerpages.net/topic/9709-ar-11-diagram/
There was another thread that's not showing up. r_laski was in it, and I think dave who is a
professor, and simulation was mentioned.