using TO-3 or TO-220 packages, i'm suppposed to design an amplifier with the following properties:
Z_in :50kΩ
Z_out: less than 0.25Ω
out : 20W @R_y=4Ω
voltage gain: 40dB @R_y=4Ω
THD( for this output and desired BW): less than 0.5% @R_y=4Ω
BW: 20Hz-20KHz (±0.5dB) @ R_y=4Ω
....................................
i'm gonna use pspice 16.3 Demo for this.
i just don't know where to start

 

Is this a class assignment?

hgmjr

 

Thousands of designs out for this that would meet your specs, try searching through some of the do it yourself audio websites where people have already designed their own amps.

Just one link of thousands: http://www.hobbyprojects.com/A/audio.html