Catch is, that you cannot use a very high power TV tube with those. The old hi Z speakers are probably somewhat limited as to current and voltage in series with the plate of a tube. You could maybe get a transformer that is a hi Z coupling trans or a capacitor for coupling to at least keep the DC out of it. But I still bet the audio power handling is not all that great in those things. Or max audio output capability. At least you could keep too much bass out of it with selected values of coupling caps and the antique 20s coupling trans apparently do not couple deep bass very well. Fry the froghair coil open, then kiss it goodby. Or you could do what some have done. Get a horn with a dead or missing driver, install a small 8 Ohm speaker inside, and then you can drive it with modern radios.
I planned on using the choke + capacitor speaker coupling that was so common on 1920's radios.
I was given this schematic from a fellow forum member and plan on building it soon. I have a single Peerless A7 reproducer and given it has at least the frequency response of decent computer speakers I thought about finding another then building two of these circuits. I would then have a very interesting pair of computer speakers