Low Voltage Home Wiring
After additional searching, I found that these power supplies are used for the full home audio system using similar (But not the same) wire as each speaker uses.  The system was never fully installed, so I didn't notice it before.
Currently all of the speakers and outputs of these power supplies are just left un-terminated in giant spool of wire in the utility room.   I don't believe this to be code compliant as the low voltage and high voltage wire share a single conduit.