A
less safe approach would be to convert the radio to a hot chassis design.
If, and it's a big if, the circuits inside are not tied directly to the chassis (this might have been done to make the radio useable in a positive ground car and in a negative ground car). You'd change the tubes to their 12V equivalents, and the audio output to its 50V heater equivalent, and the rectifier to the usual hot chassis rectifier circuit.[/QUOTE]
I saw this approach on a 4V31 Zenith farm radio. They used the vibrator transformer reverse wired, to provide the heater voltage and used a selenium rectifier for the B+, connected right to the line.
Hot chassis and a real hack conversion.
