Does any one owns tube portable radios that have F.M.?

[Josef]

If you plan to run the radio from batteries only this ist totally fine.
If you run it from mains, it needs the diodes or a new battery to avoid blowing the tube filaments from overvoltage.
The advantage of the diode circuit is: it will last forever- a new battery will fail again sooner or later

BTW: This portable radio has two output tubes too for the same reason you already mentioned:

https://www.radiomuseum.org/r/radione_r20.html

Edit: Of course the Radione R20 only has one AF output tube but this radio has two:

https://www.radiomuseum.org/r/minerv...able_531f.html