2A3A class tube push-pull amplifier

2A3 is a low internal resistance direct-heating transistor, and its internal resistance is only 800Ω, so the load impedance from screen to screen of the output transformer is only 3.5kΩ. The screen voltage of the push-pull power amplifier tube is 360~380V, the cathode-to-ground voltage is 60~80V, the total operating current of the power amplifier is 80~100mA, and the maximum output power can reach 15W. The distortion coefficient of this machine is 1% ~ 2%, and the frequency response is from 20Hz ~ 40kHz ± 2dB.