A HI-FI tube power amplifier 01

Due to the use of high-performance materials and advanced technology, the frequency response of the output transformer of this machine can reach 10Hz (-0.8dB) ~
50Hz (- ldB), which lays the foundation for improving the indicators of the entire machine.
    Each group of voltages in the power supply part of the machine is shown in Figure 1-42. The three rectifier bridges are composed of four 1N4007s respectively. Rl,. R2
is the voltage equalizing resistor of Cl, C2, C3 and C4 to prevent the two capacitors from being connected in series. At this time, an overvoltage is caused due to uneven partial pressure. The relay
is used to realize high voltage delay control, and this machine uses its normally open contact group. R3 is a power resistor. Since
there is a voltage difference of 500v-360V-140V between the relay Kl output and VT1 output, R3 is added to reduce the requirements for the VT1 tube. R3 is
60V (40mA>a. R4 is 82kn. C6 is lO fiF , used to reduce ripple output. VD13~VD15 are voltage stabilizing diodes, and the voltage
reaches about 360V. VT1 and VT2 are connected in Darlington form to obtain better voltage stabilizing effect. C7 and C9 are high-frequency
filtering The capacitor is o.lrdrFp. R5 is the same as R3 to share power consumption. R5 is 1.5kfl. R6 and R4 are 82kfl + C7-
C 5. VT1 and VT2 use high-voltage high-power transistors 2SC3306, and VT3 is a medium-power transistor 2SC3743.