The principle of power amplifier selection is:
1. The transformer power is greater than or equal to 1.5-2 times the rated power of the power amplifier.
2. Select the filter capacitor as 1000u-2200u per A current. For example, the maximum output current of LM1875 is 4A, and the filter capacitor should not be less than 6800u.
3. The voltage withstand value of the electrolytic capacitor is 2 times the root of the actual working voltage (that is, 1.41 times).
4. The filter electrolytic capacitor is connected in parallel with a 0.1u small capacitor, which can reduce the high frequency internal resistance and is very effective in improving the sound quality. Transformer choose E line on the line, if there is a shielding layer between the first stage better.