Yea I knew it was similar, but not sure how close.I believe these are similar to RCA BA1A (schematic attached) but don't know that from experience, just an unverified fact stuck in my brain.
I just bought them and they haven't arrived yet, as soon as they do I will post detailed pics. It looks to me though from the pics above to have the same size transformers as the ba1.What are the numbers on the bottom of the transformers? If you post good pictures we can figure out a schematic. I've seen these for sale before and been curious. I'd suspect they don't have the same quality of transformers as a ba-1 or ba-2 or they would be highly sought after