Ordinary power amplifiers are low-resistance outputs, usually 4 ohms to 16 ohms, while constant-voltage power amplifiers are high-resistance outputs (up to 70 ohms to 100 ohms), which can transmit audio current at a long distance.

If you use a constant voltage power amplifier, you need to connect a professional sound column, and there is an impedance transformation transformer inside the sound column to transform the impedance. If you use an ordinary speaker, you need to connect 8 ohms output, and the effect is not as good as the sound column.