This is a great thread and I will be keeping Eds_53's material for my own reference.
Most of the people that repair these old radios can do the conversion to 12v for you. The tubes are generally the same number with the initial "6" replaced by "12". As a note of interest, those Buick radios have a tuning coil set which can be sustituted for the original in the 51 to 53 AD radio. This comes in very handy when you have a valuable radio with a broken tuning coil!
