You will need an old round twin flat AC plug. I do not have one.
Mine is a circular twin flat which I temporary use to power it up. No AC cord is included.
The rectifier tube is a 5Y3 vacuum tube. Thank You and Good Luck :. The item "Tube Power Supply For Jensen M18 Field Coil Speaker 300VDC @ 2amps Maximum" is in sale since Sunday, March 22, 2020. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Amplifiers & Tube Amps". The seller is "mono" and is located in Fairfax, Virginia.This item can be shipped worldwide.