Interstage Audio Transformer Recommendations

[MT70B]

I am working on an Amrad Symphony (Model 81) TRF radio from the late 20's early 30's. It was passed down to my father-in-law and now to me. It needs a replacement interstage audio transformer that feeds the grids of the push-pull 45 tubes from the first audio stage's 27 tube. The transformer in the radio has both an open primary and one half of the secondary. So I think it is toast (think materials used to pot it inside the metal box may have gotten the best of it over the years). I have been looking around for a suitable substitution and thought I would ask for recommendations from the forum.

What you you recommend, and why so I can learn from your experience.

Thanks!

Mike

PS if you want to see the schematic it can be found here: http://www.nostalgiaair.org/resources/065/M0001065.htm