Fully symmetrical VMOS amplifier

VTi ~ VT6 form a double differential input stage with a constant current source. A feedback resistor (№ ~ R) is connected to the emitter of each differential tube.
It acts as a negative feedback current, which can reduce open-loop distortion and improve
Linear dynamic range can also balance the pairing error of the differential tube.
    VT7 and VT8 form a symmetrical complementary voltage amplifier stage, VTio, v, r l form an output push stage, VTg, VT)2, etc.
form an output bias circuit.
    VTi2 ~ VTis form a complementary push-pull power output stage composed of FETs connected in parallel, which can output low power. If
smaller power needs to be output, a pair of tubes can be used for push-pull output. Field effect transistors connected in parallel for power output can increase the output power
and reduce the output internal resistance. However, parallel connection of multiple tubes has the disadvantages of increasing the input capacitance, increasing the burden on the front stage and reducing the conversion rate
.
    Rzz and R17+RPi form a feedback loop, which determines the gain of the entire machine.
    Adjust RPz so that the quiescent current of the output tube is 30mAo.
    In addition to the selection of circuit components marked in the connection diagram, you can also refer to the previous circuit selection.