[GreenKeys] enlighten me regarding Model 19 rectifier

[Jim Haynes]

Most Teletype rectifiers used constant-voltage transformers.  These 
require pretty accurate AC power frequency, so the thyratron models are
used in applications where the frequency is not constant.  Such as
military situations running off generator sets.   There are also some
rectifiers regulated by magnetic amplifiers that presumably came after
the thyratron models.

If all you need is a local loop supply, just build one out of parts.

jhhaynes at earthlink dot net