While playing the guitar many times there is a problem that unwanted noise can appear. Hence the need for a guitar noise gate. It happened specifically to a high-gain circuit is very sensitive to the surrounding radio signal.
This circuit is the old and well-known NE555 integrated circuits based. DC to DC circuit is not complicated, little parts, and doing pretty much stable voltage. It produces with the 12V DC voltage of 30V to voltage. The NE555 constant operating frequency is set. The 3 pin voltage convert of 30V. D1- D4 and C1-C5 voltage tripler circuit. DC to DC converter is use in similar tube circuit.
Recently I found this interesting distortion fuzz circuit with 2n3904 transistors. The Howie’s Metal Simplex. I immediately liked, to build and testing. This is a silicon fuzz circuit. Interesting solution uses LED signal cut, although similar topology as old Fuzz Face.
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.