About the power supply, the filaments can be powered by AC or DC except that the 3a5 (version 2 of the amplifier) requires a DC filamentsupply.
就电源而言，灯丝用交、直流供电均可，但是版本二中的3a5除外，它必须用直流供电。
2
The switch mode regulated power supply using self - adjusting technique is introduced. In TV transmitter, it is used to the large power transmit-ting tubes with variable voltage for cold filament.
Electric supply of filament adopts constant voltage device, which has high voltage stabilizing accuracy, long life and distinct energy-saving efficiency.