300B Hi-Fi Power Amplifier

300B is a power amplifier transistor with high reliability and excellent characteristics . When designing the circuit , the excellent characteristics of 300B should
be fully utilized. In order to match the preheating time of the 300B filament, the WE-274 rectifier diode was developed, and
the amplifier produced this time uses Toshiba 1S2 711 silicon diode with high rectification efficiency. Considering the 300B filament preheating time,
the bias supply method D using both fixed grid bias and self-supplied bias is adopted. The entire circuit structure is shown in Figure 1-46. The whole machine
uses a triode port. The second harmonic distortion generated by the final power amplifier tube 300B is
offset by the reverse second harmonic specially generated by the voltage amplifier stage at the final stage, so no negative feedback is used.