I was dimensioning the CE capacitor. To do that I was looking at some formulas seen in class. The formula (freq_C=1/(2*piReqC)) involves the knowledge of the loop gain (open loop gain*beta). It appears to be negative in my schematic. What does it mean? Is something wrong? In other exercises I've got a positive number: I though positive numbers were to be expected. This is the audio amplifier circuit I'm working on:
-- update --
@Tony Stewart Sunnyskyguy EE75 I have upgraded the circuit but I haven't applied the 3:1 resistors value ratio in the Vbe multiplier since the quiescent current on the output resistors was several hundreds mA... The circuit is behaving better now though. Do you think that something is wrong?
The fact that I have good phase margin (+90.8deg) and good gain margin (-37.8dB) (do you agree?) isn't enough to assure me stability? It looks like I still need miller compensation capacitor since I've got peaking. Why do i have peaking though?