Hello,
Here is a link to photobucket. It shows a Rogers replacement tube manual that includes info on replacing the two 2X3’s with a 5Y3G, 80, or 5Y4G.
https://s169.photobucket.com/albums/u205 … _Tube-Sub/
Thanks to Jim Frey and John Bartley at the Antique Radio Forum for sharing the information.
-ferris