David,  I am a Hammond organ lover and collector.  As you know, the
BA was only produced in limited numbers.  In my opinion, the Hammond
sounds much better with a Leslie 122 then a Hammond tone cabinet would.
If you have both it can be very nice as well.  The tone cabinet sounds
best in either a large room or a room with ideal acoustics.

The tone cabinets that pretty much came with the Hammond B organs were
a PR40.  They are all over eBay auction, but are very heavy to ship.
For the money I would suggest a 122 Leslie.

I have a Hammond model D from around the same time that the BA came out
and I have both a tone cabinet and a 122 Leslie, all of which I restored
a year and a half ago.  I would be willing to record it being played
using both and then each separately and let you decide.

Yours, Dan Fenner
Freeville, New York