I am working on a Electrohome ” Cosmic ” 5 tube radio that the audio transformer is missing . The output tube is a 50B5 . So what is needed is a small 2.5 k ohm to 8 ohm .
If you want to test your radio a 120 volt to 6.3 volt small power transformer will be close enough, impedance wise to work.
It is actually about 2900 to 8 .
a 6.3 volt with a 115 volt primary is even better at 2660 to 8.