I tack soldered this phase shift oscillator together and used a 2N7000 MOSFET for the PSO. The second transistor in the upper right is a 2N4401 being used as an emitter follower to drive the LED. The LED would draw too much current and load down the oscillator – the PSO has to have a voltage gain of at least 29 to oscillate.
The three orange capacitors are 1 uF each. The 4.3 megohm resistors connect them to the drain and gate. The 4.7k resistor is the drain load resistor. The remaining 220 ohm resistor is to limit the current through the LED. The circuit oscillates subsonically, less than 1 Hz. This is dependent on the 4.3 meg resistors and 1 uF capacitors. The 2N7000 gate draws no current so the resistors can be very high without disturbing the bias. The supply voltage is about 5 volts.