The schematic shows electrical connections not necessarily the layout in the radio. The 71A drives the speaker and has 5 volts for filament. If a 26 is inserted in the 71A socket it will burn out within seconds. I've done this more than once..
Norm
: Your schematic shown on the radiola 18 must have come from the same book as I have in which the tube layout shown is INCORRECT.,The #1 tube (shown as a 226),should be a '71' & the #6 tube (shown as a 71) should be a '226'-The radio will work somewhat w/tubes in as shown in schematic but will squeal & almost no selectivity..Just swap the '71 & the '226 & it should be a lot better...Duffy/.Radiolab