TEA-1000 power amplification improvement example 02

I encountered a case where the protection resistor was burned out (open circuit). During the repair, a high-power
triode 3DD15 was installed at the output end of 78 1 2 (the same type of tube with greater power is better), and coupled with a radiator, it will be stable. The voltage output is connected to the base of the high-power tube, the collector of
the high-power tube is connected to the input terminal of 7 8 1 2, and the emitter is used as the output. Connect it to the filament port of the electron tube Vl. V2. At the same time, considering
the voltage drop of the emitter junction of the power tube, the output voltage will be lower than 12.6V, and two diodes
1N 4148 are added below 7 8 1 2. The output voltage is stabilized at a voltage close to 13V (not affected by power grid fluctuations), as shown in Figure 2-30. After the modification,
the output internal resistance of the circuit is greatly reduced to meet the power consumption of the electronic tube filament. When working, the heat generated by this part of the circuit is greatly reduced
.