New dual loop power amplifier

In the signal power amplifier circuit composed of VT1, VT2, VT5~VT11, etc.,
appropriate local negative feedback is added to each stage, a large loop negative feedback capacitor is used, and a transistor with a high characteristic frequency is selected to reduce
the transient interaction. Adjust distortion, improve transient response, widen the passband and reduce the startup impact sound. The notable feature of this power amplifier is that
VT3, VT4 and VT5-VT11 form another DC negative feedback amplification circuit and the above signal power amplification circuit .
Simple forms are combined to form two closed loops 6 that are interconnected in structure and have independent working processes. This is the so-called
"double loop" power amplifier. The two loops work together to make the output of the amplifier static DC zero potential. Very
stable. If the output DC potential Uo rises for some reason, Uo can be reduced to Ov through feedback and DC amplification.
C3 and C4 in the circuit are used to filter out the AC component in the feedback signal , so that the loop where VT3 and VT4 are located has no AC negative feedback effect .
C2 can balance the bases of the two tubes VT3 and VT4 with the ground, reducing the noise of the switch.