[Arran]

Quote: " I don't believe that there were power supplies built for the 2V / 90V, 2V / 135V 6V or 32V radios" There was, there was another "Electro" model designed for the pre war 2 volt sets, and a Silvertone Power Shftr for the same, I've never seen the Electro one other then in old magazine ads, and the Silverone one is not very common, according to Radiotvphononut. One thing that could be done with the 2 volt sets was to operate the filaments with a wet cell, so I think that many were kept in service that way since all you had to do was tap off of one cell of a storage battery. My experience with farm sets is that many survived because they were put into closets, or basements, once the power lines came into an area. Also I've never heard of a "Trade in Event" where the battery radios were destroyed afterward, you have to remember that many of these sets were purchased through mail order catalogs, like Sears, Montgomery Ward, Eatons, Simpsons, or the Hudson's Bay Company, because the owners lived in remote or semi remote areas off the grid. I have seen the odd set that was electrified by converting the set to AC tubes, and several botched attempts at same. Most of the successful conversions were with outboard power supplies with sockets provided for the battery plugs, which is another strike against that BEAR power supply with the allegator clips.
Brand Z I think did offer AC and 6 volt sets, so did Sentinel, I'm sure others did as well since many manufacturers were based in the greater Chicago area. Those would have been the models that used AC tubes, so adding an extra primary for the vibrator would have been simple enough, not sure if they used a synchronous vibrator or a rectifier tube, in both modes, or in alternate modes, like the synchronous vibrator for 6 volt only. I only have one 32 volt radio, and it's a Phonola based off of a Wells Gardner design, the 6 volt Stewart Warner set I have uses 2 volt battery tubes in a series-parallel arrangement, and a synchronous vibrator.
Regards
Arran