varient of the AA5 I've never seen
 

http://pw2.netcom.com/~subminiature/...5diaa12AU6.jpg

I've seen 4 tube radios use this 12AU6 converter circuit for the front end. But never in a radio with an IF amp tube (like a 12BA6). Maybe because the 12AU6 converter has no provision for AVC action? I think if you try to AVC the grid 1 of the 12AU6 circuit, it may quit working.

Not sure why any radio maker ever used this 12AU6 circuit, the osc coil is special, as well as the IF transformer (with the tapped primary). The standard 12BE6 circuit would have worked, and the parts except maybe the tube itself would be cheaper.