Battery-Drive Single tube AM Transmitter

Can tubes work with 10V B+ or around? The answer is 'YES!'. Most of tubes can work with far below the data sheets. Here I show an example as Single tube Amplitude Modulator that works 4 of AA NiH Battery (Heater/B+) and 6F22 006P 9V Dry Battery (B+). This 5BK7A MW Band modulator can output 530-770kHz, 60% modulation depth, Max. 4.5Vpp radio wave with the battery power. If changing the heater voltage, various other double triodes can also work, such as 12BH7A, 9AU7, 8CG7, 6N6P, 4BQ7A, ... etc

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