This is the low frequency power amplifier of which the penumbra article can be composed without using it is hardly. The about 660-mW output can be gotten with the 16-ohm speaker.
This circuit is used for the simple monitor and so on. The impedance (4-ohm and 8-ohm, and so on), the output power of the speaker and so on are specified by the standard but are OK rather than strict. Because the sound cracks (warping) when presenting the output above the rating, it uses naturally within the standard. When conscious of the timbre and the output power, it is better not to do the use of this circuit.
