Homemade 100Wx2HI-FI power amplifier

Many audiophiles like to use Sanyo's ST K series power amplifier circuits, such as STK4131, STK4191
, etc. However, the fly in the ointment is that these power amplifiers use transistor outputs, and their frequency response, distortion, dynamic range and other indicators are not high. Here
we introduce to readers a high-fidelity power amplifier audio mixing integrated circuit STK2100 I with excellent performance.
    ST K2100 I is an audiophile-grade high-power amplifier integrated circuit. Its output uses a power field effect with electron tube characteristics.
The output power of the tube is 100w×2, the frontal response is 10Hz~20kHz, the circuit operating voltage is the lowest ±12V, the highest is earth sov, and
the distortion is 0.01%. Use it to make high-quality products The peripheral circuit of the power amplifier is very simple, with low distortion, and parameters such as frequency band and output power
have reached excellent indicators. The circuit is shown in Figure 5-84. VD3 is the speaker bridge pickup circuit. When the power amplifier circuit is normal,
R and l only have AC signals and no DC voltage. The pickup circuit does not work, VT1 is cut off, and VT2 and VT3 are on. , K pulls in, and
the amplifier output is connected to the speaker. When a circuit failure occurs, VT1 is turned on, VT2 and VT3 are cut off, K is released, and the speaker is
effectively protected.