Hello all, I have a late twenties low boy Deforest-Crosley that has 3 24A tubes and 47 output,originally 45 but got changed at some time, socket and all.Anyways I decided to disconnect the speaker leads leaving field coil still intact of course and hooked up a medium size closed back ported Hi Fi speaker, same impedance as speaker in radio.I tested first with ohm meter and the sound that issued forth was amazing!The bass and volume jumped to life.Of course the speaker in the radio probably needs some cone work but what a difference.I would like to put a hidden switch somewhere that would allow you to use either the radio speaker for original sound or switch to a remote speaker to really make it more HiFi (not quite)but still really dynamic

You could use a Mono Head phone jack. Just plug it in to cut out the original speaker, feeding the box speaker then. I would think the original speaker should sound almost as good though. Maybe fix the speaker first.

Putting a hi-fi audio signal through an old radio with a good speaker can sound nice. But if it goes through the RF section as an AM signal, the highs will be lost (the outer portion of the sidebands will likely be cut off). The bass will sound great (particularly with the highs cut off).

I have a 15-tube E.H. Scott receiver (2A3s in push-pull) with a phono jack. I can play my CDs through that and they sound great. I don't have the original Scott speaker, so I'm using a modern full-range Fostex speaker in a reflex enclosure.
Doug