I recently picked up a giant and excessively overengineered radio from the second world war. It was a superheterodyne, but it used a choke power supply, and surprisingly, a 60-600-6000R SE output. The output transformer is a Thordarson, it lists a gap for 30ma dc, and an 8,000 ohm primary. Frequency response (as listed on the transformer's pot) is 75-15k, I'm assuming at one to three db. The model number for the transformer is T-46789. The chassis of the radio is stamped 1943.