For a couple of months now, based on my own listening, and listings on their website, it looks like CHML in Hamilton, Ontario is rebroadcasting classic episodes of "The Jack Benny Program" every Sunday night at 10:05 P.M. Eastern time.
CHML is at 900 on the AM dial with a 50,000-watt signal, albeit quite directional. You can hear it roughly anywhere inside a triangle whose points are Hamilton, Ontario; Boston; and Atlantic City.
Outside that area, you can go to their website, http://www.900chml.com at the appropriate time, and click-on the link to "Listen Live".