Simple structure high-fidelity power amplifier

The circuit principle is shown in Figure 240. The circuit structure is very simple. It only uses 4 transistors to realize the entire process of the circuit from input, voltage amplification
, inversion, promotion and power amplifier. Moreover, the technical indicators of the circuit are very high, making it an excellent high-fidelity Power amplifier
circuit.
 VTi is the input stage, which uses a PNP tube as the input stage and has an impedance matching function. VTz is a voltage amplification
stage and has both CE inversion and push functions. VT3 and VT4 form a complementary push-pull power amplifier output stage o
R7, R and A negative feedback loop has been formed and determines the circuit gain: Av-R7 is 8-2.7/0.22, combined with 21dBo.
C3 is the bootstrap capacitor, and R6 is the isolation resistor.