This circuit has a sensitivity of 200 mV providing an RMS power of around 4 W for a load of 8 ohms with 12 V supply. The source must have excellent filtering and the output transistors must be equipped with good heat radiators. For one channel the source must be at least 1 A and for two channels, the source must be double. The input cable must be shielded, given the sensitivity of the circuit to noise.
