Electronic – Building 3 Stage amplifier, Couple Questions


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General question, how can I improve it? or make it more efficient? mabye there is something im missing…


  1. How can I deliver more dc voltage to the load? how do I improve my swing, im getting around 5.5volt
  2. How can I improve the voltage distortion when increasing voltage input?
  3. My phase is shifted in the output? tried to increase C7 didnt help.
  4. How to improve BW and CMRR?

Best Answer

Maybe something like this


simulate this circuit – Schematic created using CircuitLab

You have to decide if the entire amplifier (gain of 10,000) is viable.

1) Can the non-Darlington Q1/Q2 be a light enough load that Q5 (transconductor) and Q7 (stiff current source/load) will provide 100X gain?

2) can you achieve another gain of 100X in a diffpair, if the load is D1+R4

3) how to achieve negative feedback

4) how to generate a BODE plot, so you can examine the gain margin and the phase margin

5) how to compensate the entire amplifier, even if the load (not shown) happens to be a reactive (inductive, capacitive) loud speaker load of 16 ohms?

6) does the output swing around GROUND (so you need +- 12volts, or you need a large output DC_blocking cap (not shown))

7) how to bias the input?

8) is base of Q3, or of Q4, the input?

9) what is the low-end rolloff, if C2 and R9 set that highpass response?