Simple Audio Amplifier For Learning Purpose

[circuitcity]

Hello Everyone

I would like to learn the foundation of elementary electronics involved with designing a linear audio amplifier (class ab ideally). The final design might be produced. But my main aim is to design and simulate a working circuit on circuitmaker and learn the foundations ultimately. This is a private pet project which I am doing in my spare time on the weekends.

My knowledge so far of linear amplifiers is the 3 stage Architecture. The transcoductance stage, Transimpedance stage (Voltage-amplification stage) and output stage.

The transcoductance stage is a voltage controlled current source essentially that is comprised of a differential amplifier.

I have initially started the design of the linear amplifier with just a simple differential amplifier, composed of two npn transistors. In circuitmaker I just simulated the circuit to set the Q-point of the differential amp.

Like So

Imageshack - diffamp1.png

Now is where I am confused. How do i proceed from here onwards. I grounded one transistors base and feeded a 1KHz/ 1volt sinusoidal signal at the base of the other transistor. The single-ended output of the diff amp was taken into a ideal op-amp comprised of a transimpedance stage. But I don't know how if my testing and simulation method is correct.

Like so

Imageshack - circuit1x.png

I'll post the waveforms if requested. But I would say they are very wrong at the moment.

Whatever theory I got wrong, please correct me.
Cheers

 

[lineup]

You have chosen a good start. Diff pair.
And you have most of it right.
Now, those things that are not right
... they are what you will learn best from .. and never forget.
Some little practice some days in a week
and soon you will handle SPICE almost like you handle your bike or car.

 

[circuitcity]

lol.. You forgot to tell me what are the things that are wrong in terms of my theory and understanding and also the circuit.