Pure DC FET power amplifier circuit 03

22. This field effect tube amplifier is suitable for those who are obsessed with the sound of electronic tubes but cannot produce beautiful sounds for various reasons.
Audiophile 9 This bipolar field effect tube amplifier has very similar output characteristics to those of electronic tubes. The frequency characteristics Good, the tone
is similar to that of the amplifier and amplifier, and it is more ideal if it is coupled with a tube preamplifier. Q SRPP tube preamplifier circuit, as shown in Figure 7-256.
    The circuit is a parallel adjustable push-pull circuit, and the fork can be called The shunt-adjusted push-pull circuit was originally used for high-frequency input stages, such as
VHF/UHF tube high-frequency head circuits, but is used for AF input, regardless of distortion, linearity, amplification, dynamics and low
output impedance. It is comprehensively superior to ordinary Class A triode amplifiers, and contrary to many other tube circuit designs,
the distortion rate of the SRPP circuit decreases as the frequency increases.
    This circuit is obviously two tubes connected in series. How can it be a parallel adjustable push-pull circuit? This is for AC work , the DC
power supply mode of the two tubes is connected in series, each carrying half of the power supply voltage. But it is different for AC signals. The screen electrode of the upper tube is connected to the ground. The input is taken from the screen electrode of the lower tube, and the negative output (shared screen circuit) is used. In this way, the tubes work in parallel. . Because the gate of the electron tube works at a negative angle relative to the cathode , the bias circuit is extremely simple. This principle cannot be used in transistor or op amp circuits.