[Eliot Ness]

I checked my Rider, Beitman, and Gernsback service manuals last night but could not find any of the following sets:

Acratone 25B
Simplex 4Z
Zephyr 4Z

I did see a partial ad for the Acratone 25B and it looks like the Century (first radio listed):

http://www.wa2ise.com/radios/acratone.html

And in the fine print for the Acratone 25B ad that I linked to on RadioMuseum they mention that the 76 is used as the rectifier.

You just need to get rid of that line cord. Personally I'd use a diode and then a capacitor or resistor to drop the voltage. The diode will get you down to about 85 volts. The following site (near the end) gives you the formula to calculate the size capacitor you'd need. As Tom mentioned, you'd use a non-polarized cap.

http://www.vintage-radio.com/repair-rest...calcs.html