My Crosley 50
 

Found locally on CL. Excellent condition. Comes with the original headphones. Neatest thing (to me) is that it comes from the original family. Supposedly a descendant of Leon Foucault for you science geeks. Not sure I understand yet the voltages or how to tune it but that leaves some fun to be had.

Book capacitor. Designed efficient and inexpensive.

Very nice find. I have the ACE V, which is basically the same set. If it has a good original brass-based UV-200/201, you just hook-up a lantern 6V battery for the A supply and 3 transistor 9V's snapped together for the B supply. As far as tuning, you can't go wrong. Just fiddle with all front controls. Usually the filament voltage (arrow knob) needs to be up fully. I use my transmitter, so antenna is not a problem, but it will require a long antenna to tune in stations.

Interesting:
I have never seen or heard before about such a capacitor. Seeing it in opened position would be great.
BTW: This will be one of the first radios which turn 100 in 4 or 5 years :thmbsp:

Here's a closeup. Insulator sheet appears intact

Before I add power to this, I want to be sure I have the power correct. I run the B- to the same post as the A+ ? B being the high voltage?

You run B- to whichever A terminal doesn't have the filament adjustment resistor.

You need 500 ohm or higher headphones or speaker for it and you connect the phones/speaker between the speaker and B+ post. 20s sets didn't use output transformers to match impedance (though you could do that with it now) and instead used high impedance phones/speaker.

This PDF file has '20's radio hook-up diagrams including one for yours. Just scroll down to it:
http://arbeiii.com/ARBE-III%20Compil...20Diagrams.pdf