Unknown vintage output transformer 15k:600

Vintage output transformer - from memory, this was salvaged from a pro tape recorder (early transistor era) so probably has decent frequency response. Shielded enclosure (soldered). With the following markings:
1594I, 73-4-2
Primary 15,000 ohms @5mA DC
Secondary: 62.5, 150, 250 or 600 ohms

Any known circuit designs out there calling for a transformer like this?
Can this transformer be directly coupled with a tube output stage (e.g. 12AU7)?
What else might it be good for?
Can it handle balanced I/O (given the separate shield terminal)?

Any suggestions -- tubes, circuits, topologies -- would be appreciated. Had this for a long time, I'm weighing up whether to finally build something simple and straightforward, like a microphone preamp, or sell it on.
 

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