50WOTL power amplifier circuit

The circuit principle is shown in Figure 2-1. This circuit has high technical indicators and is a very excellent OTL power amplifier circuit . The frequency response
of the circuit is 10Hz ~ 100kH, and the total harmonic distortion rate is <0.1%, which is rare in general (YFL power amplifiers). The     barrier circuit consists of four parts: input stage, impedance conversion stage, inverter stage and power output stage. Resistor-capacitor coupling stages are used between stages, and there is no large-loop DC negative feedback. Since each stage has deep local feedback, the operating point of the circuit is very stable. VTi     and its peripheral components form the input stage. In order to To improve the input impedance and the stability of the circuit, a large-value resistor of 1_5kfl is used as the emitter of rTc.     VT2 and VT3 form a direct coupling amplifier. It is coupled with the input stage by capacitor C3 . Rl l is the negative feedback circuit of this stage. Resistance is used to stabilize the operating point of this stage. oVT3 adopts the emitter output mode to reduce the output impedance, facilitate matching with the inverter stage VT4, and improve the driving ability of the inverter stage VT4.