[Arran]

The only place in my area, where I am certain that they had DC mains service, which was the only true 110 volt system that I know of, was in a hotel that was originally owned by Canadian Pacific called "The Empress" in downtown Victoria, it had DC service up until the 1960s when the place received one of it's many renovations. The reason I know this is that people, whom had statyed there, have told me that they had no television sets in the rooms until the 1970s. The Empress was built in the 1890s so I suspect they had their own power plant on site since electricity would have been a novelty at the time, I'm guessing that the elevators were the main reason why they were slow to change.
  There was electricity fairly early on in my area due to a number of coal mines, they had their own dam and power station as well, but it was 115 volt at 25 cps. It was all converted over to 120 volt 60 cycles per second in 1958, so I do run into a fair number of radios with 25 cycle transformers, if they also had a phonograph the motor was usually replaced, in other appliances they had to be replaced or rewound. An AC/DC radio wouldn't care what the power line frequency was, though it may need bigger filter caps to deal with the ripple. 
Regards
Arran