12AU7 Tube tremolo
This is a Hybrid tube tremolo circuit. It is interesting that a low frequency oscillator (LFO) in electron tube is not resolved, we do circuit transistor for low frequency.
BC547 transistors and used ECC82 or 12AU7, so the circuit operates at low voltage. Tube circuit provides classic, warm sine wave tremolo tones.
12AU7 Tube circuit
The single ECC82 / 12AU7 runs at low voltage for a full, rich and dynamic sound tube. Its advantage is that only the guitar signal passes through the tube. With controls for volume, speed and depth it is very simple to set up great sounding tremolo. Led indicates the oscillator operating frequency. Here, the oscillator is directly connected to the cathode through the 1N4148 diode (V1B). Other circuits resolved optical means (incandescent or LED + photocell). In another version, try it.