Need help on designing aspects of audio amplifier
I have just begun a hobby of building audio amplifiers. I have been studying a basic amplifier lately that contains a differential input stage, a common emitter gain stage, and a darlington push-pull output stage. The amplifier is said to be rated at 60 watts. I understand how the amplifier works but I am confused on the design aspects of the audio amplifier.
My question is how would one go about designing an amplifier from scratch. Do you start out with specs that you would wish to accomplish, then attempt to design a topology? At what stage do you consider the quiescent current values, resistor values, etc.; and how do you come up with those values? How do you select the transistors; do you base your selection on gain, maximum current rating, or anything else? At what stage in the design phase do you consider what types of transistors to use? Are all the selection of bias conditions, component values, and component types based on estimations or is it based on precision calculations?
Any information on how you go about designing an amplifier would be appreciated. I basically would like to know what kind of design phases you go through and in what order.
Thanks a bunch.