I built the version in post #2, and I don't seem to be set the idle current to 400 mA. Supply voltage 24V, R10 is 10 Ohms, the Schottkys are SB360, the Fet-s are IRF530-s, their gate is at 3.7V (Vgs), but the idle current does not go over 60 mA. I double checked everything, it works even this way but there is audile distortion at higher volumes (no oscillation). Any idea or advice?
Some update:
I have another class AB amplifier circuit using IRF540/9540 as mentioned before. I removed the MOSFETs from the circuit board and using flying leads to connect, and try to remove all overlapping wires (of course not shorted) within the circuit board. This amplifier can function properly with reasonable power output, provided that I connect the loudspeaker (4 Ohm) and the input to the audio jack of mobile phone BEFORE connecting the power supply (24 V). Also I found that the power rockets with noise. For safety purpose I connect a fuse to protect the board.
For this amplifier circuit, I still cannot find a way to resolve the problem of huge power.
Any idea? Is this related to stray capacitance?
I have another class AB amplifier circuit using IRF540/9540 as mentioned before. I removed the MOSFETs from the circuit board and using flying leads to connect, and try to remove all overlapping wires (of course not shorted) within the circuit board. This amplifier can function properly with reasonable power output, provided that I connect the loudspeaker (4 Ohm) and the input to the audio jack of mobile phone BEFORE connecting the power supply (24 V). Also I found that the power rockets with noise. For safety purpose I connect a fuse to protect the board.
For this amplifier circuit, I still cannot find a way to resolve the problem of huge power.
Any idea? Is this related to stray capacitance?