So I built the Wien bridge oscillator without automatic gain control and I am using a preset to tune the circuit instead.
My question is this, so when I reduce the gain of the op-amp to something smaller than 3, I can see the oscillations die out slowly on my oscilloscope. When I turn the preset and increase the gain to maybe 3.2 I still get stable oscillations, but larger Vpp and no clipping. Considering the Barkhausen criterion shouldn't the circuit render unstable, and the oscillations begin to clip?
This only happens when I increase the gain to larger values than 3.4. For a gain approximately equal to 3.3 I get a very weird sine wave almost about to clip. I'm curious to why this behaviour is incremental, I thought for a gain greater than 3, it should automatically clip.
For reference I am using the UA741 and my circuit is configured the same as the picture I included.
Values of capacitors are 10nF and resistors are 1060 ohm to obtain 15kHz oscillations. R4 is equivalent to my preset (20k) and R3 is composed of two resistors in serioes of 20k each.