Vintage Amplifier Service Manual - KNIGHT model 93-103 6-tube 20-watt audio amplifier. Manufactured by Allied Radio Corp., of Chicago, IL. Dated 1948. 2 pages. Original old Sams Photofact manual includes schematic, layout, alignment instructions, voltage & resistance test chart, repair parts list and description. This manual would make a sensational accompaniment to your retro public address audio equipment.