They are both great frames. They were both great picks for competition in the day. The AA was earlier (mid 70s on) and the models were carried paralel in the early 80s. I think the AA was discontinued around mide 80s. In fact its place was taken by models like AA Special en AA Super. The AB was carried till mid 90s.
The AA ranked above the AB. It is a bit more luxurious. A few differences: for the AA the bb shell comes from Roto Italy or Cinelli, another crown is used, there is an 'X' reinforcement behind the bb instead of a tube.
Recently fellow forummember jvs posted many catalogues
Take a look.
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