I did my spice analysis using the built-in model for the 2N3904 transistor.
I decided to determine the actual β for each transistor at its operating point. I inserted a 1 milliohm resistor in series with each base and collector. I then applied a small (.05 mV) 1 kHz signal at the input, and had spice calculate the ratio Ic/Ib for each transistor. You have to be sure to only calculate the ratio for the AC component of the signals.
I also adjusted the value of RFB until the signal at the emitter of Q1 was essentially zero. For my spice analysis, this happened when RFB was 2240 ohms.
Spice takes into account things that our simple model in this thread doesn't take into account.
I decided to determine the actual β for each transistor at its operating point. I inserted a 1 milliohm resistor in series with each base and collector. I then applied a small (.05 mV) 1 kHz signal at the input, and had spice calculate the ratio Ic/Ib for each transistor. You have to be sure to only calculate the ratio for the AC component of the signals.
I also adjusted the value of RFB until the signal at the emitter of Q1 was essentially zero. For my spice analysis, this happened when RFB was 2240 ohms.
Spice takes into account things that our simple model in this thread doesn't take into account.