Quote:
Originally Posted by radiotvnut
I've got a circa '46 Emerson AC/DC/battery portable on the way that's interesting. It uses dual output tubes. In AC, a 50B5 is switched into circuit. In DC, a 3Q5 is switched into circuit. They probably did this so that the radio would have more volume and better tonal quality when used on AC.
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I have about three of those Emersons. Two of them use the 35W4 and 50B5 combination and one uses a 117N7. It's a very interesting design, to be sure. All the tube filaments, except the 3Q4 are supplied from the cathode of the output tube, when operated on the power line. As a result of this design, no large wattage resistor is needed for the tube filaments. As an added bonus, the power output is around one watt, compared to the others with the conventional design, using the battery output tube, giving only around 350 miliwatts of output.
There is a few other radio manufacturers that built a radio with a similar circuit.