[Mondial]

Looks like someone wanted the best possible sound from that set and cost was no object. Those UTC transformers were the finest available and were very expensive even when new. Even with AM's limited audio frequency range, the improved bass response of these transformers would be noticeable. It appears that the mods were done early in the radio's life as UTC painted their transformers gray by the 1950's.

The 6A5G's are great tubes with their indirectly heated cathodes, are really what should have been designed into the radio in the first place.

It appears that the person who modified this radio really knew what they were doing.