The radio has two 950 audio output tubes. Requires 90 volts B supply, 2 volts A supply and -4.5 C supply.
Looks like its from mid 30's.
http://www.nostalgiaair.org/ has the Riders 8-30 schematic under "resources".
http://www.radioatticarchives.com/radio.htm?radio=4663 is your photo
My Air Castle 604 farm set is similar in operation (40's) but has totally different tubes.