With the op amp getting better sound, I wish to build a samll and easy power amp with it.
I would to build the simplest first, op amp driving a pair of Mos fet or BJT devices.
Mos Fet will be more sensitive to drive, this will be similar to Sheldon stokes head phone amp, with +/- 15 v power supply, and bigger closed loop gain of 30 or 40, such that I could drive it with CD player easily. I am not sure how much power I can get from here. Assuming +/- 10 Volts output swing, the output for 8 ohm speaker will be 100/8 = 12.5 watts. Is this assumption correct? I have some IRF 9530, and 531. Though th erateing of 531 is slihtly lower, I assume it will be ok for 15V dual power supply.
If I use BJT, I would build it in stages, first with just a pair of emitter followers, such as MJE 15034/15035. With op amp that is capable of more then 50 ma output drive, and beta of 100, we could have an output of 5 Ampere, sufficient to produce 12 watts output. If it does not work, perhaps I will add BC 550/560 to drive the MJE 15034/35.
Any advise on this please?
Tks and rgds
William Lee
I would to build the simplest first, op amp driving a pair of Mos fet or BJT devices.
Mos Fet will be more sensitive to drive, this will be similar to Sheldon stokes head phone amp, with +/- 15 v power supply, and bigger closed loop gain of 30 or 40, such that I could drive it with CD player easily. I am not sure how much power I can get from here. Assuming +/- 10 Volts output swing, the output for 8 ohm speaker will be 100/8 = 12.5 watts. Is this assumption correct? I have some IRF 9530, and 531. Though th erateing of 531 is slihtly lower, I assume it will be ok for 15V dual power supply.
If I use BJT, I would build it in stages, first with just a pair of emitter followers, such as MJE 15034/15035. With op amp that is capable of more then 50 ma output drive, and beta of 100, we could have an output of 5 Ampere, sufficient to produce 12 watts output. If it does not work, perhaps I will add BC 550/560 to drive the MJE 15034/35.
Any advise on this please?
Tks and rgds
William Lee