What are these? Transformers maybe?

[Demonkleaner]

 

[Galu]

Looks like a plug in microphone transformer.

 

[rayma]

Could be an audio line transformer. Often plug into an octal tube socket.

 

[Galu]

The Polyphase Instrument Co. provides custom designed transformers.

 

[Demonkleaner]

Thanks. They plug into a standard miniature 7-pin socket.

 

[Galu]

Miniature 7-pin would indicate a microphone transformer to me.

 

[Osvaldo de Banfield]

They also may be presision filter networks.